Use caret for peer dependency

* Change import path from zos-lib to upgrades in all contracts

* Update readme with new naming

* Update package and deps names

* Change path to initializable in AST of networks.jsons

* Migrate manifest version

* Use new oz file locations

* Rename in ERC20Migrator comments

* Update SDK install instructions in README

* Update gitignore to use new session file name

* trigger CI

* Fixes to readme and package version

* Use 2.5.0 release of OpenZeppelin SDK

.env.example

@@ -1,5 +0,0 @@
-# configure your infura api key (not technically required)
-INFURA_API_KEY=
-
-# change the mnemonic that your hd wallet is seeded with
-MNEMONIC=

.eslintrc

@@ -1,22 +1,23 @@
 {
   "extends" : [
     "standard",
-    "plugin:promise/recommended"
+    "plugin:promise/recommended",
   ],
   "plugins": [
-    "promise"
+    "mocha-no-only",
+    "promise",
   ],
   "env": {
     "browser" : true,
     "node"    : true,
     "mocha"   : true,
-    "jest"    : true
+    "jest"    : true,
   },
   "globals" : {
     "artifacts": false,
     "contract": false,
     "assert": false,
-    "web3": false
+    "web3": false,
   },
   "rules": {
 
@@ -49,6 +50,8 @@
     "semi": ["error", "always"],
     "space-before-function-paren": ["error", "always"],
 
+    "mocha-no-only/mocha-no-only": ["error"],
+
     "promise/always-return": "off",
     "promise/avoid-new": "off",
   }

.github/ISSUE_TEMPLATE.md

@@ -1,34 +0,0 @@
-## 🎉 Description
-
-<!-- Briefly describe the issue you are experiencing (or the feature you want to see added to OpenZeppelin). Tell us what you were trying to do and what happened instead. **Remember, this is _not_ a place to ask for help debugging code; for that, we welcome you in the [OpenZeppelin Slack Channel](https://slack.openzeppelin.org/).** -->
-
-- [ ] 🐛 This is a bug report.
-- [ ] 📈 This is a feature request.
-
-<!-- Please check one of the above by placing an x in the box. -->
-
-## 💻 Environment
-
-Next, we need to know what your environment looks like.
-
-- Which version of OpenZeppelin are you using?
-- What network are you deploying to? Ganache? Ropsten?
-- How are you deploying your OpenZeppelin-backed contracts? truffle? Remix? Let us know!
-
-## 📝 Details
-
-Describe the problem you have been experiencing in more detail. Include as much information as you think is relevant. Keep in mind that transactions can fail for many reasons; context is key here.
-
-## 🔢 Code To Reproduce Issue [ Good To Have ]
-
-Please remember that with sample code it's easier to reproduce the bug and it's much faster to fix it.
-
-```
-insert short code snippets here
-```
-
-<!-- If your code is larger, consider linking us to a repo illustrating your issue. -->
-
-## 👍 Other Information
-
-<!-- List any other information that is relevant to your issue. Error logs, related issues, suggestions on how to fix, Stack Overflow links, forum links, etc. -->

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,21 @@
+---
+name: Bug report
+about: Report a bug in OpenZeppelin
+
+---
+
+<!-- Briefly describe the issue you're experiencing. Tell us what you were trying to do and what happened instead. -->
+
+<!-- Remember, this is not a place to ask for help debugging code. For that, we welcome you in the OpenZeppelin Slack channel: https://slack.openzeppelin.org/. -->
+
+**💻 Environment**
+
+<!-- Tell us what version of OpenZeppelin you're using, and how you're using it: Truffle, Remix, etc. -->
+
+**📝 Details**
+
+<!-- Describe the problem you have been experiencing in more detail. Include as much information as you think is relevant. Keep in mind that transactions can fail for many reasons; context is key here. -->
+
+**🔢 Code to reproduce bug**
+
+<!-- We will be able to better help if you provide a minimal example that triggers the bug. -->

.github/ISSUE_TEMPLATE/feature_request.md

@@ -0,0 +1,14 @@
+---
+name: Feature request
+about: Suggest an idea for OpenZeppelin
+
+---
+
+**🧐 Motivation**
+<!-- Is your feature request related to a specific problem? Is it just a crazy idea? Tell us about it! -->
+
+**📝 Details**
+<!-- Please describe your feature request in detail. -->
+
+<!-- Make sure that you have reviewed the OpenZeppelin Contributor Guidelines. -->
+<!-- https://github.com/OpenZeppelin/openzeppelin-solidity/blob/master/CONTRIBUTING.md -->

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,17 +1,22 @@
 <!-- 0. 🎉 Thank you for submitting a PR! -->
 
-<!-- 1. **Does this close any open issues?** If so, list them here. If not, remove the `Fixes #` line. -->
+<!-- 1. Does this close any open issues? Please list them below. -->
+
+<!-- Keep in mind that new features have a better chance of being merged fast if
+they were first discussed and designed with the maintainers. If there is no
+corresponding issue, please consider opening one for discussion first! -->
 
 Fixes #
 
-# 🚀 Description
-
-<!-- 2. Describe the changes introduced in this pull request -->
+<!-- 2. Describe the changes introduced in this pull request. -->
 <!--    Include any context necessary for understanding the PR's purpose. -->
 
-<!-- 3. Before submitting, please review the following checklist: -->
-
-- [ ] 📘 I've reviewed the [OpenZeppelin Contributor Guidelines](../blob/master/CONTRIBUTING.md)
-- [ ] ✅ I've added tests where applicable to test my new functionality.
-- [ ] 📖 I've made sure that my contracts are well-documented.
-- [ ] 🎨 I've run the JS/Solidity linters and fixed any issues (`npm run lint:fix`).
+<!-- 3. Before submitting, please make sure that you have:
+  - reviewed the OpenZeppelin Contributor Guidelines
+    (https://github.com/OpenZeppelin/openzeppelin-solidity/blob/master/CONTRIBUTING.md),
+  - added tests where applicable to test new functionality,
+  - made sure that your contracts are well-documented,
+  - run the Solidity linter (`npm run lint:sol`) and fixed any issues,
+  - run the JS linter and fixed any issues (`npm run lint:fix`), and
+  - updated the changelog, if applicable.
+-->

.gitignore

@@ -32,8 +32,13 @@ npm-debug.log
 # truffle build directory
 build/
 
-# lol macs
-.DS_Store/
+# macOS
+.DS_Store
 
 # truffle
 .node-xmlhttprequest-*
+
+.openzeppelin/.session
+
+# IntelliJ IDE
+.idea

.node-version

@@ -1 +0,0 @@
-v8.9.1

.openzeppelin/kovan.json

@@ -0,0 +1,945 @@
+{
+  "contracts": {
+    "TokenVesting": {
+      "address": "0x17d2e73611a9ec10ab4751c514a539ec820b953c",
+      "constructorCode": "608060405234801561001057600080fd5b50611c6c806100206000396000f3fe",
+      "bodyBytecodeHash": "ba0eade6a19e4b485aca3478c8755d2a6041a2b39a7aa1a0a73253a782c4a065",
+      "localBytecodeHash": "94b5eed89a6bab268326a5010e52000ff74d40d96c83811c9d455d7c8b54f447",
+      "deployedBytecodeHash": "94b5eed89a6bab268326a5010e52000ff74d40d96c83811c9d455d7c8b54f447",
+      "types": {
+        "t_bool": {
+          "id": "t_bool",
+          "kind": "elementary",
+          "label": "bool"
+        },
+        "t_uint256": {
+          "id": "t_uint256",
+          "kind": "elementary",
+          "label": "uint256"
+        },
+        "t_array:50<t_uint256>": {
+          "id": "t_array:50<t_uint256>",
+          "valueType": "t_uint256",
+          "length": "50",
+          "kind": "array",
+          "label": "uint256[50]"
+        },
+        "t_address": {
+          "id": "t_address",
+          "kind": "elementary",
+          "label": "address"
+        },
+        "t_mapping<t_uint256>": {
+          "id": "t_mapping<t_uint256>",
+          "valueType": "t_uint256",
+          "label": "mapping(key => uint256)",
+          "kind": "mapping"
+        },
+        "t_mapping<t_bool>": {
+          "id": "t_mapping<t_bool>",
+          "valueType": "t_bool",
+          "label": "mapping(key => bool)",
+          "kind": "mapping"
+        }
+      },
+      "storage": [
+        {
+          "contract": "Initializable",
+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "initialized",
+          "astId": 13503,
+          "type": "t_bool",
+          "src": "757:24:147"
+        },
+        {
+          "contract": "Initializable",
+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "initializing",
+          "astId": 13505,
+          "type": "t_bool",
+          "src": "876:25:147"
+        },
+        {
+          "contract": "Initializable",
+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "______gap",
+          "astId": 13554,
+          "type": "t_array:50<t_uint256>",
+          "src": "1891:29:147"
+        },
+        {
+          "contract": "Ownable",
+          "path": "contracts/ownership/Ownable.sol",
+          "label": "_owner",
+          "astId": 8198,
+          "type": "t_address",
+          "src": "472:22:108"
+        },
+        {
+          "contract": "Ownable",
+          "path": "contracts/ownership/Ownable.sol",
+          "label": "______gap",
+          "astId": 8311,
+          "type": "t_array:50<t_uint256>",
+          "src": "2415:29:108"
+        },
+        {
+          "contract": "TokenVesting",
+          "path": "contracts/drafts/TokenVesting.sol",
+          "label": "_beneficiary",
+          "astId": 3576,
+          "type": "t_address",
+          "src": "1133:28:28"
+        },
+        {
+          "contract": "TokenVesting",
+          "path": "contracts/drafts/TokenVesting.sol",
+          "label": "_cliff",
+          "astId": 3578,
+          "type": "t_uint256",
+          "src": "1263:22:28"
+        },
+        {
+          "contract": "TokenVesting",
+          "path": "contracts/drafts/TokenVesting.sol",
+          "label": "_start",
+          "astId": 3580,
+          "type": "t_uint256",
+          "src": "1291:22:28"
+        },
+        {
+          "contract": "TokenVesting",
+          "path": "contracts/drafts/TokenVesting.sol",
+          "label": "_duration",
+          "astId": 3582,
+          "type": "t_uint256",
+          "src": "1319:25:28"
+        },
+        {
+          "contract": "TokenVesting",
+          "path": "contracts/drafts/TokenVesting.sol",
+          "label": "_revocable",
+          "astId": 3584,
+          "type": "t_bool",
+          "src": "1351:23:28"
+        },
+        {
+          "contract": "TokenVesting",
+          "path": "contracts/drafts/TokenVesting.sol",
+          "label": "_released",
+          "astId": 3588,
+          "type": "t_mapping<t_uint256>",
+          "src": "1381:46:28"
+        },
+        {
+          "contract": "TokenVesting",
+          "path": "contracts/drafts/TokenVesting.sol",
+          "label": "_revoked",
+          "astId": 3592,
+          "type": "t_mapping<t_bool>",
+          "src": "1433:42:28"
+        },
+        {
+          "contract": "TokenVesting",
+          "path": "contracts/drafts/TokenVesting.sol",
+          "label": "______gap",
+          "astId": 3941,
+          "type": "t_array:50<t_uint256>",
+          "src": "6226:29:28"
+        }
+      ],
+      "warnings": {
+        "hasConstructor": false,
+        "hasSelfDestruct": false,
+        "hasDelegateCall": false,
+        "hasInitialValuesInDeclarations": false,
+        "uninitializedBaseContracts": [],
+        "storageUncheckedVars": [],
+        "storageDiff": []
+      }
+    },
+    "PaymentSplitter": {
+      "address": "0xf1e274980871d7c4aaab8d646c17728ed263e747",
+      "constructorCode": "608060405234801561001057600080fd5b506110a4806100206000396000f3fe",
+      "bodyBytecodeHash": "fe0f9da480efb9ef366284126f8d9dccff6f19f8ee0183449035b37c1f5103d8",
+      "localBytecodeHash": "d9901040952d3add936b2939fb694875bdfd7b513c877bc1942d36a5e4190873",
+      "deployedBytecodeHash": "d9901040952d3add936b2939fb694875bdfd7b513c877bc1942d36a5e4190873",
+      "types": {
+        "t_bool": {
+          "id": "t_bool",
+          "kind": "elementary",
+          "label": "bool"
+        },
+        "t_uint256": {
+          "id": "t_uint256",
+          "kind": "elementary",
+          "label": "uint256"
+        },
+        "t_array:50<t_uint256>": {
+          "id": "t_array:50<t_uint256>",
+          "valueType": "t_uint256",
+          "length": "50",
+          "kind": "array",
+          "label": "uint256[50]"
+        },
+        "t_mapping<t_uint256>": {
+          "id": "t_mapping<t_uint256>",
+          "valueType": "t_uint256",
+          "label": "mapping(key => uint256)",
+          "kind": "mapping"
+        },
+        "t_address": {
+          "id": "t_address",
+          "kind": "elementary",
+          "label": "address"
+        },
+        "t_array:dyn<t_address>": {
+          "id": "t_array:dyn<t_address>",
+          "valueType": "t_address",
+          "length": "dyn",
+          "kind": "array",
+          "label": "address[]"
+        }
+      },
+      "storage": [
+        {
+          "contract": "Initializable",
+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "initialized",
+          "astId": 13503,
+          "type": "t_bool",
+          "src": "757:24:147"
+        },
+        {
+          "contract": "Initializable",
+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "initializing",
+          "astId": 13505,
+          "type": "t_bool",
+          "src": "876:25:147"
+        },
+        {
+          "contract": "Initializable",
+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "______gap",
+          "astId": 13554,
+          "type": "t_array:50<t_uint256>",
+          "src": "1891:29:147"
+        },
+        {
+          "contract": "PaymentSplitter",
+          "path": "contracts/payment/PaymentSplitter.sol",
+          "label": "_totalShares",
+          "astId": 8418,
+          "type": "t_uint256",
+          "src": "1176:28:110"
+        },
+        {
+          "contract": "PaymentSplitter",
+          "path": "contracts/payment/PaymentSplitter.sol",
+          "label": "_totalReleased",
+          "astId": 8420,
+          "type": "t_uint256",
+          "src": "1210:30:110"
+        },
+        {
+          "contract": "PaymentSplitter",
+          "path": "contracts/payment/PaymentSplitter.sol",
+          "label": "_shares",
+          "astId": 8424,
+          "type": "t_mapping<t_uint256>",
+          "src": "1247:43:110"
+        },
+        {
+          "contract": "PaymentSplitter",
+          "path": "contracts/payment/PaymentSplitter.sol",
+          "label": "_released",
+          "astId": 8428,
+          "type": "t_mapping<t_uint256>",
+          "src": "1296:45:110"
+        },
+        {
+          "contract": "PaymentSplitter",
+          "path": "contracts/payment/PaymentSplitter.sol",
+          "label": "_payees",
+          "astId": 8431,
+          "type": "t_array:dyn<t_address>",
+          "src": "1347:25:110"
+        },
+        {
+          "contract": "PaymentSplitter",
+          "path": "contracts/payment/PaymentSplitter.sol",
+          "label": "______gap",
+          "astId": 8684,
+          "type": "t_array:50<t_uint256>",
+          "src": "5158:29:110"
+        }
+      ],
+      "warnings": {
+        "hasConstructor": false,
+        "hasSelfDestruct": false,
+        "hasDelegateCall": false,
+        "hasInitialValuesInDeclarations": false,
+        "uninitializedBaseContracts": [],
+        "storageUncheckedVars": [],
+        "storageDiff": []
+      }
+    },
+    "StandaloneERC20": {
+      "address": "0x2a79d89665d22ee56cc0efd102169fa41f27b065",
+      "constructorCode": "608060405234801561001057600080fd5b50613153806100206000396000f3fe",
+      "bodyBytecodeHash": "ad8d45945d6a4f088a61fd605c38cdf2f40171624bca2a7c3b2d4e95b068eb3d",
+      "localBytecodeHash": "bca15bc1a7aa87c603c9b185aab38e0d72b8adc6347426bb66954cef39e88a74",
+      "deployedBytecodeHash": "bca15bc1a7aa87c603c9b185aab38e0d72b8adc6347426bb66954cef39e88a74",
+      "types": {
+        "t_bool": {
+          "id": "t_bool",
+          "kind": "elementary",
+          "label": "bool"
+        },
+        "t_uint256": {
+          "id": "t_uint256",
+          "kind": "elementary",
+          "label": "uint256"
+        },
+        "t_array:50<t_uint256>": {
+          "id": "t_array:50<t_uint256>",
+          "valueType": "t_uint256",
+          "length": "50",
+          "kind": "array",
+          "label": "uint256[50]"
+        },
+        "t_string": {
+          "id": "t_string",
+          "kind": "elementary",
+          "label": "string"
+        },
+        "t_uint8": {
+          "id": "t_uint8",
+          "kind": "elementary",
+          "label": "uint8"
+        },
+        "t_mapping<t_uint256>": {
+          "id": "t_mapping<t_uint256>",
+          "valueType": "t_uint256",
+          "label": "mapping(key => uint256)",
+          "kind": "mapping"
+        },
+        "t_struct<Roles.Role>": {
+          "id": "t_struct<Roles.Role>",
+          "kind": "struct",
+          "label": "Roles.Role",
+          "members": [
+            {
+              "label": "bearer",
+              "astId": 5,
+              "type": "t_mapping<t_bool>",
+              "src": "150:32:0"
+            }
+          ]
+        },
+        "t_mapping<t_bool>": {
+          "id": "t_mapping<t_bool>",
+          "valueType": "t_bool",
+          "label": "mapping(key => bool)",
+          "kind": "mapping"
+        }
+      },
+      "storage": [
+        {
+          "contract": "Initializable",
+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "initialized",
+          "astId": 13503,
+          "type": "t_bool",
+          "src": "757:24:147"
+        },
+        {
+          "contract": "Initializable",
+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "initializing",
+          "astId": 13505,
+          "type": "t_bool",
+          "src": "876:25:147"
+        },
+        {
+          "contract": "Initializable",
+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "______gap",
+          "astId": 13554,
+          "type": "t_array:50<t_uint256>",
+          "src": "1891:29:147"
+        },
+        {
+          "contract": "ERC20Detailed",
+          "path": "contracts/token/ERC20/ERC20Detailed.sol",
+          "label": "_name",
+          "astId": 9641,
+          "type": "t_string",
+          "src": "209:20:118"
+        },
+        {
+          "contract": "ERC20Detailed",
+          "path": "contracts/token/ERC20/ERC20Detailed.sol",
+          "label": "_symbol",
+          "astId": 9643,
+          "type": "t_string",
+          "src": "235:22:118"
+        },
+        {
+          "contract": "ERC20Detailed",
+          "path": "contracts/token/ERC20/ERC20Detailed.sol",
+          "label": "_decimals",
+          "astId": 9645,
+          "type": "t_uint8",
+          "src": "263:23:118"
+        },
+        {
+          "contract": "ERC20Detailed",
+          "path": "contracts/token/ERC20/ERC20Detailed.sol",
+          "label": "______gap",
+          "astId": 9697,
+          "type": "t_array:50<t_uint256>",
+          "src": "1645:29:118"
+        },
+        {
+          "contract": "ERC20",
+          "path": "contracts/token/ERC20/ERC20.sol",
+          "label": "_balances",
+          "astId": 9129,
+          "type": "t_mapping<t_uint256>",
+          "src": "1357:46:115"
+        },
+        {
+          "contract": "ERC20",
+          "path": "contracts/token/ERC20/ERC20.sol",
+          "label": "_allowances",
+          "astId": 9135,
+          "type": "t_mapping<t_uint256>",
+          "src": "1410:69:115"
+        },
+        {
+          "contract": "ERC20",
+          "path": "contracts/token/ERC20/ERC20.sol",
+          "label": "_totalSupply",
+          "astId": 9137,
+          "type": "t_uint256",
+          "src": "1486:28:115"
+        },
+        {
+          "contract": "ERC20",
+          "path": "contracts/token/ERC20/ERC20.sol",
+          "label": "______gap",
+          "astId": 9516,
+          "type": "t_array:50<t_uint256>",
+          "src": "7875:29:115"
+        },
+        {
+          "contract": "MinterRole",
+          "path": "contracts/access/roles/MinterRole.sol",
+          "label": "_minters",
+          "astId": 219,
+          "type": "t_struct<Roles.Role>",
+          "src": "271:27:2"
+        },
+        {
+          "contract": "MinterRole",
+          "path": "contracts/access/roles/MinterRole.sol",
+          "label": "______gap",
+          "astId": 319,
+          "type": "t_array:50<t_uint256>",
+          "src": "1133:29:2"
+        },
+        {
+          "contract": "ERC20Mintable",
+          "path": "contracts/token/ERC20/ERC20Mintable.sol",
+          "label": "______gap",
+          "astId": 9746,
+          "type": "t_array:50<t_uint256>",
+          "src": "816:29:119"
+        },
+        {
+          "contract": "PauserRole",
+          "path": "contracts/access/roles/PauserRole.sol",
+          "label": "_pausers",
+          "astId": 339,
+          "type": "t_struct<Roles.Role>",
+          "src": "271:27:3"
+        },
+        {
+          "contract": "PauserRole",
+          "path": "contracts/access/roles/PauserRole.sol",
+          "label": "______gap",
+          "astId": 439,
+          "type": "t_array:50<t_uint256>",
+          "src": "1133:29:3"
+        },
+        {
+          "contract": "Pausable",
+          "path": "contracts/lifecycle/Pausable.sol",
+          "label": "_paused",
+          "astId": 4481,
+          "type": "t_bool",
+          "src": "855:20:37"
+        },
+        {
+          "contract": "Pausable",
+          "path": "contracts/lifecycle/Pausable.sol",
+          "label": "______gap",
+          "astId": 4564,
+          "type": "t_array:50<t_uint256>",
+          "src": "2105:29:37"
+        },
+        {
+          "contract": "ERC20Pausable",
+          "path": "contracts/token/ERC20/ERC20Pausable.sol",
+          "label": "______gap",
+          "astId": 9869,
+          "type": "t_array:50<t_uint256>",
+          "src": "1178:29:120"
+        }
+      ],
+      "warnings": {
+        "hasConstructor": false,
+        "hasSelfDestruct": false,
+        "hasDelegateCall": false,
+        "hasInitialValuesInDeclarations": false,
+        "uninitializedBaseContracts": [],
+        "storageUncheckedVars": [
+          {
+            "contract": "MinterRole",
+            "path": "contracts/access/roles/MinterRole.sol",
+            "label": "_minters",
+            "astId": 219,
+            "type": "t_struct<Roles.Role>",
+            "src": "271:27:2"
+          },
+          {
+            "contract": "PauserRole",
+            "path": "contracts/access/roles/PauserRole.sol",
+            "label": "_pausers",
+            "astId": 339,
+            "type": "t_struct<Roles.Role>",
+            "src": "271:27:3"
+          }
+        ],
+        "storageDiff": [
+          {
+            "action": "rename",
+            "updated": {
+              "index": 8,
+              "contract": "ERC20",
+              "path": "contracts/token/ERC20/ERC20.sol",
+              "label": "_allowances",
+              "astId": 9135,
+              "type": "t_mapping<t_uint256>",
+              "src": "1410:69:115"
+            },
+            "original": {
+              "index": 8,
+              "contract": "ERC20",
+              "path": "contracts/token/ERC20/ERC20.sol",
+              "label": "_allowed",
+              "astId": 8173,
+              "type": "t_mapping<t_uint256>",
+              "src": "827:66:110"
+            }
+          }
+        ]
+      }
+    },
+    "StandaloneERC721": {
+      "address": "0x61e5b805911ba82de487e13de1e375a6130004f0",
+      "constructorCode": "608060405234801561001057600080fd5b50614299806100206000396000f3fe",
+      "bodyBytecodeHash": "9113153cb4b2b62f720cb12960ba3b4a7b9a5f3329e34a4a3ece0212d130ae53",
+      "localBytecodeHash": "5dca693db1fee9a4ce973e49d6665a8770b823c36ba2c7e64f37d81046672074",
+      "deployedBytecodeHash": "5dca693db1fee9a4ce973e49d6665a8770b823c36ba2c7e64f37d81046672074",
+      "types": {
+        "t_bool": {
+          "id": "t_bool",
+          "kind": "elementary",
+          "label": "bool"
+        },
+        "t_uint256": {
+          "id": "t_uint256",
+          "kind": "elementary",
+          "label": "uint256"
+        },
+        "t_array:50<t_uint256>": {
+          "id": "t_array:50<t_uint256>",
+          "valueType": "t_uint256",
+          "length": "50",
+          "kind": "array",
+          "label": "uint256[50]"
+        },
+        "t_mapping<t_bool>": {
+          "id": "t_mapping<t_bool>",
+          "valueType": "t_bool",
+          "label": "mapping(key => bool)",
+          "kind": "mapping"
+        },
+        "t_address": {
+          "id": "t_address",
+          "kind": "elementary",
+          "label": "address"
+        },
+        "t_mapping<t_address>": {
+          "id": "t_mapping<t_address>",
+          "valueType": "t_address",
+          "label": "mapping(key => address)",
+          "kind": "mapping"
+        },
+        "t_struct<Counters.Counter>": {
+          "id": "t_struct<Counters.Counter>",
+          "kind": "struct",
+          "label": "Counters.Counter",
+          "members": [
+            {
+              "label": "_value",
+              "astId": 2533,
+              "type": "t_uint256",
+              "src": "1022:14:22"
+            }
+          ]
+        },
+        "t_mapping<t_struct<Counters.Counter>>": {
+          "id": "t_mapping<t_struct<Counters.Counter>>",
+          "valueType": "t_struct<Counters.Counter>",
+          "label": "mapping(key => Counters.Counter)",
+          "kind": "mapping"
+        },
+        "t_array:dyn<t_uint256>": {
+          "id": "t_array:dyn<t_uint256>",
+          "valueType": "t_uint256",
+          "length": "dyn",
+          "kind": "array",
+          "label": "uint256[]"
+        },
+        "t_mapping<t_array:dyn<t_uint256>>": {
+          "id": "t_mapping<t_array:dyn<t_uint256>>",
+          "valueType": "t_array:dyn<t_uint256>",
+          "label": "mapping(key => uint256[])",
+          "kind": "mapping"
+        },
+        "t_mapping<t_uint256>": {
+          "id": "t_mapping<t_uint256>",
+          "valueType": "t_uint256",
+          "label": "mapping(key => uint256)",
+          "kind": "mapping"
+        },
+        "t_string": {
+          "id": "t_string",
+          "kind": "elementary",
+          "label": "string"
+        },
+        "t_mapping<t_string>": {
+          "id": "t_mapping<t_string>",
+          "valueType": "t_string",
+          "label": "mapping(key => string)",
+          "kind": "mapping"
+        },
+        "t_struct<Roles.Role>": {
+          "id": "t_struct<Roles.Role>",
+          "kind": "struct",
+          "label": "Roles.Role",
+          "members": [
+            {
+              "label": "bearer",
+              "astId": 5,
+              "type": "t_mapping<t_bool>",
+              "src": "150:32:0"
+            }
+          ]
+        }
+      },
+      "storage": [
+        {
+          "contract": "Initializable",
+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "initialized",
+          "astId": 13503,
+          "type": "t_bool",
+          "src": "757:24:147"
+        },
+        {
+          "contract": "Initializable",
+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "initializing",
+          "astId": 13505,
+          "type": "t_bool",
+          "src": "876:25:147"
+        },
+        {
+          "contract": "Initializable",
+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "______gap",
+          "astId": 13554,
+          "type": "t_array:50<t_uint256>",
+          "src": "1891:29:147"
+        },
+        {
+          "contract": "ERC165",
+          "path": "contracts/introspection/ERC165.sol",
+          "label": "_supportedInterfaces",
+          "astId": 4117,
+          "type": "t_mapping<t_bool>",
+          "src": "550:52:31"
+        },
+        {
+          "contract": "ERC165",
+          "path": "contracts/introspection/ERC165.sol",
+          "label": "______gap",
+          "astId": 4162,
+          "type": "t_array:50<t_uint256>",
+          "src": "1714:29:31"
+        },
+        {
+          "contract": "ERC721",
+          "path": "contracts/token/ERC721/ERC721.sol",
+          "label": "_tokenOwner",
+          "astId": 10508,
+          "type": "t_mapping<t_address>",
+          "src": "829:48:125"
+        },
+        {
+          "contract": "ERC721",
+          "path": "contracts/token/ERC721/ERC721.sol",
+          "label": "_tokenApprovals",
+          "astId": 10512,
+          "type": "t_mapping<t_address>",
+          "src": "933:52:125"
+        },
+        {
+          "contract": "ERC721",
+          "path": "contracts/token/ERC721/ERC721.sol",
+          "label": "_ownedTokensCount",
+          "astId": 10516,
+          "type": "t_mapping<t_struct<Counters.Counter>>",
+          "src": "1043:63:125"
+        },
+        {
+          "contract": "ERC721",
+          "path": "contracts/token/ERC721/ERC721.sol",
+          "label": "_operatorApprovals",
+          "astId": 10522,
+          "type": "t_mapping<t_bool>",
+          "src": "1161:73:125"
+        },
+        {
+          "contract": "ERC721",
+          "path": "contracts/token/ERC721/ERC721.sol",
+          "label": "______gap",
+          "astId": 11065,
+          "type": "t_array:50<t_uint256>",
+          "src": "12696:29:125"
+        },
+        {
+          "contract": "ERC721Enumerable",
+          "path": "contracts/token/ERC721/ERC721Enumerable.sol",
+          "label": "_ownedTokens",
+          "astId": 11117,
+          "type": "t_mapping<t_array:dyn<t_uint256>>",
+          "src": "445:50:127"
+        },
+        {
+          "contract": "ERC721Enumerable",
+          "path": "contracts/token/ERC721/ERC721Enumerable.sol",
+          "label": "_ownedTokensIndex",
+          "astId": 11121,
+          "type": "t_mapping<t_uint256>",
+          "src": "565:53:127"
+        },
+        {
+          "contract": "ERC721Enumerable",
+          "path": "contracts/token/ERC721/ERC721Enumerable.sol",
+          "label": "_allTokens",
+          "astId": 11124,
+          "type": "t_array:dyn<t_uint256>",
+          "src": "679:28:127"
+        },
+        {
+          "contract": "ERC721Enumerable",
+          "path": "contracts/token/ERC721/ERC721Enumerable.sol",
+          "label": "_allTokensIndex",
+          "astId": 11128,
+          "type": "t_mapping<t_uint256>",
+          "src": "778:51:127"
+        },
+        {
+          "contract": "ERC721Enumerable",
+          "path": "contracts/token/ERC721/ERC721Enumerable.sol",
+          "label": "______gap",
+          "astId": 11459,
+          "type": "t_array:50<t_uint256>",
+          "src": "8994:29:127"
+        },
+        {
+          "contract": "ERC721Metadata",
+          "path": "contracts/token/ERC721/ERC721Metadata.sol",
+          "label": "_name",
+          "astId": 11526,
+          "type": "t_string",
+          "src": "266:20:130"
+        },
+        {
+          "contract": "ERC721Metadata",
+          "path": "contracts/token/ERC721/ERC721Metadata.sol",
+          "label": "_symbol",
+          "astId": 11528,
+          "type": "t_string",
+          "src": "313:22:130"
+        },
+        {
+          "contract": "ERC721Metadata",
+          "path": "contracts/token/ERC721/ERC721Metadata.sol",
+          "label": "_tokenURIs",
+          "astId": 11532,
+          "type": "t_mapping<t_string>",
+          "src": "381:45:130"
+        },
+        {
+          "contract": "ERC721Metadata",
+          "path": "contracts/token/ERC721/ERC721Metadata.sol",
+          "label": "______gap",
+          "astId": 11663,
+          "type": "t_array:50<t_uint256>",
+          "src": "3029:29:130"
+        },
+        {
+          "contract": "MinterRole",
+          "path": "contracts/access/roles/MinterRole.sol",
+          "label": "_minters",
+          "astId": 219,
+          "type": "t_struct<Roles.Role>",
+          "src": "271:27:2"
+        },
+        {
+          "contract": "MinterRole",
+          "path": "contracts/access/roles/MinterRole.sol",
+          "label": "______gap",
+          "astId": 319,
+          "type": "t_array:50<t_uint256>",
+          "src": "1133:29:2"
+        },
+        {
+          "contract": "ERC721MetadataMintable",
+          "path": "contracts/token/ERC721/ERC721MetadataMintable.sol",
+          "label": "______gap",
+          "astId": 11733,
+          "type": "t_array:50<t_uint256>",
+          "src": "1042:29:131"
+        },
+        {
+          "contract": "PauserRole",
+          "path": "contracts/access/roles/PauserRole.sol",
+          "label": "_pausers",
+          "astId": 339,
+          "type": "t_struct<Roles.Role>",
+          "src": "271:27:3"
+        },
+        {
+          "contract": "PauserRole",
+          "path": "contracts/access/roles/PauserRole.sol",
+          "label": "______gap",
+          "astId": 439,
+          "type": "t_array:50<t_uint256>",
+          "src": "1133:29:3"
+        },
+        {
+          "contract": "Pausable",
+          "path": "contracts/lifecycle/Pausable.sol",
+          "label": "_paused",
+          "astId": 4481,
+          "type": "t_bool",
+          "src": "855:20:37"
+        },
+        {
+          "contract": "Pausable",
+          "path": "contracts/lifecycle/Pausable.sol",
+          "label": "______gap",
+          "astId": 4564,
+          "type": "t_array:50<t_uint256>",
+          "src": "2105:29:37"
+        },
+        {
+          "contract": "ERC721Pausable",
+          "path": "contracts/token/ERC721/ERC721Pausable.sol",
+          "label": "______gap",
+          "astId": 11878,
+          "type": "t_array:50<t_uint256>",
+          "src": "850:29:133"
+        }
+      ],
+      "warnings": {
+        "hasConstructor": false,
+        "hasSelfDestruct": false,
+        "hasDelegateCall": false,
+        "hasInitialValuesInDeclarations": false,
+        "uninitializedBaseContracts": [],
+        "storageUncheckedVars": [
+          {
+            "contract": "ERC721",
+            "path": "contracts/token/ERC721/ERC721.sol",
+            "label": "_ownedTokensCount",
+            "astId": 10516,
+            "type": "t_mapping<t_struct<Counters.Counter>>",
+            "src": "1043:63:125"
+          },
+          {
+            "contract": "MinterRole",
+            "path": "contracts/access/roles/MinterRole.sol",
+            "label": "_minters",
+            "astId": 219,
+            "type": "t_struct<Roles.Role>",
+            "src": "271:27:2"
+          },
+          {
+            "contract": "PauserRole",
+            "path": "contracts/access/roles/PauserRole.sol",
+            "label": "_pausers",
+            "astId": 339,
+            "type": "t_struct<Roles.Role>",
+            "src": "271:27:3"
+          }
+        ],
+        "storageDiff": [
+          {
+            "action": "typechange",
+            "updated": {
+              "index": 7,
+              "contract": "ERC721",
+              "path": "contracts/token/ERC721/ERC721.sol",
+              "label": "_ownedTokensCount",
+              "astId": 10516,
+              "type": "t_mapping<t_struct<Counters.Counter>>",
+              "src": "1043:63:125"
+            },
+            "original": {
+              "index": 7,
+              "contract": "ERC721",
+              "path": "contracts/token/ERC721/ERC721.sol",
+              "label": "_ownedTokensCount",
+              "astId": 9505,
+              "type": "t_mapping<t_uint256>",
+              "src": "988:54:120"
+            }
+          }
+        ]
+      }
+    }
+  },
+  "solidityLibs": {},
+  "proxies": {},
+  "manifestVersion": "2.2",
+  "frozen": true,
+  "app": {
+    "address": "0xf5829d56998ccc1405b7eabccac78164af270d39"
+  },
+  "package": {
+    "address": "0xb6f8f11b166d526932ee04ffe4d25b810f619e34"
+  },
+  "provider": {
+    "address": "0x200194fd3013c88ab2b3c84e2c885aba42a3df5d"
+  },
+  "version": "2.2.0"
+}

.openzeppelin/mainnet.json

@@ -0,0 +1,851 @@
+{
+  "contracts": {
+    "StandaloneERC721": {
+      "address": "0x8c9900276e5eD54C104d743a6E01B7041acab40f",
+      "constructorCode": "608060405234801561001057600080fd5b506136c6806100206000396000f3fe",
+      "bodyBytecodeHash": "1f3ce589a0ba1fad4f98754bd97f051852e7dbb5522d49a7185defb3e377d347",
+      "localBytecodeHash": "84a5a6731b4686c34ef5acfcf4474af2e61b3e4e0b10ea96418e4b7bd1074cbc",
+      "deployedBytecodeHash": "84a5a6731b4686c34ef5acfcf4474af2e61b3e4e0b10ea96418e4b7bd1074cbc",
+      "types": {
+        "t_bool": {
+          "id": "t_bool",
+          "kind": "elementary",
+          "label": "bool"
+        },
+        "t_uint256": {
+          "id": "t_uint256",
+          "kind": "elementary",
+          "label": "uint256"
+        },
+        "t_array:50<t_uint256>": {
+          "id": "t_array:50<t_uint256>",
+          "valueType": "t_uint256",
+          "length": "50",
+          "kind": "array",
+          "label": "uint256[50]"
+        },
+        "t_mapping<t_bool>": {
+          "id": "t_mapping<t_bool>",
+          "valueType": "t_bool",
+          "label": "mapping(key => bool)",
+          "kind": "mapping"
+        },
+        "t_address": {
+          "id": "t_address",
+          "kind": "elementary",
+          "label": "address"
+        },
+        "t_mapping<t_address>": {
+          "id": "t_mapping<t_address>",
+          "valueType": "t_address",
+          "label": "mapping(key => address)",
+          "kind": "mapping"
+        },
+        "t_struct<Counters.Counter>": {
+          "id": "t_struct<Counters.Counter>",
+          "kind": "struct",
+          "label": "Counters.Counter",
+          "members": [
+            {
+              "label": "_value",
+              "astId": 2415,
+              "type": "t_uint256",
+              "src": "1021:14:22"
+            }
+          ]
+        },
+        "t_mapping<t_struct<Counters.Counter>>": {
+          "id": "t_mapping<t_struct<Counters.Counter>>",
+          "valueType": "t_struct<Counters.Counter>",
+          "label": "mapping(key => Counters.Counter)",
+          "kind": "mapping"
+        },
+        "t_array:dyn<t_uint256>": {
+          "id": "t_array:dyn<t_uint256>",
+          "valueType": "t_uint256",
+          "length": "dyn",
+          "kind": "array",
+          "label": "uint256[]"
+        },
+        "t_mapping<t_array:dyn<t_uint256>>": {
+          "id": "t_mapping<t_array:dyn<t_uint256>>",
+          "valueType": "t_array:dyn<t_uint256>",
+          "label": "mapping(key => uint256[])",
+          "kind": "mapping"
+        },
+        "t_mapping<t_uint256>": {
+          "id": "t_mapping<t_uint256>",
+          "valueType": "t_uint256",
+          "label": "mapping(key => uint256)",
+          "kind": "mapping"
+        },
+        "t_string": {
+          "id": "t_string",
+          "kind": "elementary",
+          "label": "string"
+        },
+        "t_mapping<t_string>": {
+          "id": "t_mapping<t_string>",
+          "valueType": "t_string",
+          "label": "mapping(key => string)",
+          "kind": "mapping"
+        },
+        "t_struct<Roles.Role>": {
+          "id": "t_struct<Roles.Role>",
+          "kind": "struct",
+          "label": "Roles.Role",
+          "members": [
+            {
+              "label": "bearer",
+              "astId": 5,
+              "type": "t_mapping<t_bool>",
+              "src": "150:32:0"
+            }
+          ]
+        }
+      },
+      "storage": [
+        {
+          "contract": "Initializable",
+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "initialized",
+          "astId": 11836,
+          "type": "t_bool",
+          "src": "757:24:140"
+        },
+        {
+          "contract": "Initializable",
+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "initializing",
+          "astId": 11838,
+          "type": "t_bool",
+          "src": "876:25:140"
+        },
+        {
+          "contract": "Initializable",
+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "______gap",
+          "astId": 11887,
+          "type": "t_array:50<t_uint256>",
+          "src": "1891:29:140"
+        },
+        {
+          "contract": "ERC165",
+          "path": "contracts/introspection/ERC165.sol",
+          "label": "_supportedInterfaces",
+          "astId": 3974,
+          "type": "t_mapping<t_bool>",
+          "src": "496:52:31"
+        },
+        {
+          "contract": "ERC165",
+          "path": "contracts/introspection/ERC165.sol",
+          "label": "______gap",
+          "astId": 4018,
+          "type": "t_array:50<t_uint256>",
+          "src": "1229:29:31"
+        },
+        {
+          "contract": "ERC721",
+          "path": "contracts/token/ERC721/ERC721.sol",
+          "label": "_tokenOwner",
+          "astId": 10031,
+          "type": "t_mapping<t_address>",
+          "src": "829:48:122"
+        },
+        {
+          "contract": "ERC721",
+          "path": "contracts/token/ERC721/ERC721.sol",
+          "label": "_tokenApprovals",
+          "astId": 10035,
+          "type": "t_mapping<t_address>",
+          "src": "933:52:122"
+        },
+        {
+          "contract": "ERC721",
+          "path": "contracts/token/ERC721/ERC721.sol",
+          "label": "_ownedTokensCount",
+          "astId": 10039,
+          "type": "t_mapping<t_struct<Counters.Counter>>",
+          "src": "1043:63:122"
+        },
+        {
+          "contract": "ERC721",
+          "path": "contracts/token/ERC721/ERC721.sol",
+          "label": "_operatorApprovals",
+          "astId": 10045,
+          "type": "t_mapping<t_bool>",
+          "src": "1161:73:122"
+        },
+        {
+          "contract": "ERC721",
+          "path": "contracts/token/ERC721/ERC721.sol",
+          "label": "______gap",
+          "astId": 10568,
+          "type": "t_array:50<t_uint256>",
+          "src": "11658:29:122"
+        },
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+    "address": "0x778dddF23Ec1B5Cb18394c6C110480CaaDB3B0f6"
+  },
+  "provider": {
+    "address": "0xdd3e0B83e5462FD4Ba012FF05A57f709FA050458"
+  },
+  "version": "2.2.0"
+}

.openzeppelin/project.json

@@ -0,0 +1,12 @@
+{
+  "manifestVersion": "2.2",
+  "name": "@openzeppelin/contracts-ethereum-package",
+  "publish": true,
+  "version": "2.2.0",
+  "contracts": {
+    "StandaloneERC20": "StandaloneERC20",
+    "StandaloneERC721": "StandaloneERC721",
+    "TokenVesting": "TokenVesting",
+    "PaymentSplitter": "PaymentSplitter"
+  }
+}

.openzeppelin/rinkeby.json

@@ -0,0 +1,945 @@
+{
+  "contracts": {
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+      "address": "0x29d58ac2407f62caf9b1e00f0d7088d8c8590703",
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+      "deployedBytecodeHash": "d9901040952d3add936b2939fb694875bdfd7b513c877bc1942d36a5e4190873",
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+          "label": "uint256"
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+          "valueType": "t_uint256",
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+          "valueType": "t_address",
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+          "label": "address[]"
+        }
+      },
+      "storage": [
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+          "label": "initialized",
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+          "type": "t_bool",
+          "src": "757:24:147"
+        },
+        {
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+          "type": "t_bool",
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+        },
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+          "label": "______gap",
+          "astId": 13554,
+          "type": "t_array:50<t_uint256>",
+          "src": "1891:29:147"
+        },
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+          "label": "_totalShares",
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+          "type": "t_uint256",
+          "src": "1176:28:110"
+        },
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+          "label": "_totalReleased",
+          "astId": 8420,
+          "type": "t_uint256",
+          "src": "1210:30:110"
+        },
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+          "label": "_shares",
+          "astId": 8424,
+          "type": "t_mapping<t_uint256>",
+          "src": "1247:43:110"
+        },
+        {
+          "contract": "PaymentSplitter",
+          "path": "contracts/payment/PaymentSplitter.sol",
+          "label": "_released",
+          "astId": 8428,
+          "type": "t_mapping<t_uint256>",
+          "src": "1296:45:110"
+        },
+        {
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+          "path": "contracts/payment/PaymentSplitter.sol",
+          "label": "_payees",
+          "astId": 8431,
+          "type": "t_array:dyn<t_address>",
+          "src": "1347:25:110"
+        },
+        {
+          "contract": "PaymentSplitter",
+          "path": "contracts/payment/PaymentSplitter.sol",
+          "label": "______gap",
+          "astId": 8684,
+          "type": "t_array:50<t_uint256>",
+          "src": "5158:29:110"
+        }
+      ],
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+        "hasSelfDestruct": false,
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+        },
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+          "type": "t_array:50<t_uint256>",
+          "src": "1891:29:147"
+        },
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+          "label": "_owner",
+          "astId": 8198,
+          "type": "t_address",
+          "src": "472:22:108"
+        },
+        {
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+          "label": "______gap",
+          "astId": 8311,
+          "type": "t_array:50<t_uint256>",
+          "src": "2415:29:108"
+        },
+        {
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+          "label": "_beneficiary",
+          "astId": 3576,
+          "type": "t_address",
+          "src": "1133:28:28"
+        },
+        {
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+          "label": "_cliff",
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+          "type": "t_uint256",
+          "src": "1263:22:28"
+        },
+        {
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+          "label": "_start",
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+          "type": "t_uint256",
+          "src": "1291:22:28"
+        },
+        {
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+          "label": "_duration",
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+          "type": "t_uint256",
+          "src": "1319:25:28"
+        },
+        {
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+          "label": "_revocable",
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+        },
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+        },
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+    "StandaloneERC20": {
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+          "label": "Roles.Role",
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+        },
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+          "label": "_name",
+          "astId": 9641,
+          "type": "t_string",
+          "src": "209:20:118"
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+          "label": "_symbol",
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+          "type": "t_string",
+          "src": "235:22:118"
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+          "label": "_decimals",
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+          "type": "t_uint8",
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+        },
+        {
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+        },
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+          "contract": "ERC20",
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+          "label": "_balances",
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+          "type": "t_mapping<t_uint256>",
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+        },
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+          "label": "_allowances",
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+          "type": "t_mapping<t_uint256>",
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+          "label": "_totalSupply",
+          "astId": 9137,
+          "type": "t_uint256",
+          "src": "1486:28:115"
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+        {
+          "contract": "ERC20",
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+          "type": "t_array:50<t_uint256>",
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+          "label": "_minters",
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+          "type": "t_struct<Roles.Role>",
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+          "type": "t_array:50<t_uint256>",
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+          "label": "______gap",
+          "astId": 9746,
+          "type": "t_array:50<t_uint256>",
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+        },
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+          "label": "_pausers",
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+          "type": "t_struct<Roles.Role>",
+          "src": "271:27:3"
+        },
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+          "label": "______gap",
+          "astId": 439,
+          "type": "t_array:50<t_uint256>",
+          "src": "1133:29:3"
+        },
+        {
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+          "path": "contracts/lifecycle/Pausable.sol",
+          "label": "_paused",
+          "astId": 4481,
+          "type": "t_bool",
+          "src": "855:20:37"
+        },
+        {
+          "contract": "Pausable",
+          "path": "contracts/lifecycle/Pausable.sol",
+          "label": "______gap",
+          "astId": 4564,
+          "type": "t_array:50<t_uint256>",
+          "src": "2105:29:37"
+        },
+        {
+          "contract": "ERC20Pausable",
+          "path": "contracts/token/ERC20/ERC20Pausable.sol",
+          "label": "______gap",
+          "astId": 9869,
+          "type": "t_array:50<t_uint256>",
+          "src": "1178:29:120"
+        }
+      ],
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+            "type": "t_struct<Roles.Role>",
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+          },
+          {
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+            "path": "contracts/access/roles/PauserRole.sol",
+            "label": "_pausers",
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+            "type": "t_struct<Roles.Role>",
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+        "storageDiff": [
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+              "label": "_allowances",
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+              "type": "t_mapping<t_uint256>",
+              "src": "827:66:110"
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+          "label": "Counters.Counter",
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+              "src": "1022:14:22"
+            }
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+          "label": "Roles.Role",
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+              "type": "t_mapping<t_bool>",
+              "src": "150:32:0"
+            }
+          ]
+        }
+      },
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+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "initialized",
+          "astId": 13503,
+          "type": "t_bool",
+          "src": "757:24:147"
+        },
+        {
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+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "initializing",
+          "astId": 13505,
+          "type": "t_bool",
+          "src": "876:25:147"
+        },
+        {
+          "contract": "Initializable",
+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "______gap",
+          "astId": 13554,
+          "type": "t_array:50<t_uint256>",
+          "src": "1891:29:147"
+        },
+        {
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+          "path": "contracts/introspection/ERC165.sol",
+          "label": "_supportedInterfaces",
+          "astId": 4117,
+          "type": "t_mapping<t_bool>",
+          "src": "550:52:31"
+        },
+        {
+          "contract": "ERC165",
+          "path": "contracts/introspection/ERC165.sol",
+          "label": "______gap",
+          "astId": 4162,
+          "type": "t_array:50<t_uint256>",
+          "src": "1714:29:31"
+        },
+        {
+          "contract": "ERC721",
+          "path": "contracts/token/ERC721/ERC721.sol",
+          "label": "_tokenOwner",
+          "astId": 10508,
+          "type": "t_mapping<t_address>",
+          "src": "829:48:125"
+        },
+        {
+          "contract": "ERC721",
+          "path": "contracts/token/ERC721/ERC721.sol",
+          "label": "_tokenApprovals",
+          "astId": 10512,
+          "type": "t_mapping<t_address>",
+          "src": "933:52:125"
+        },
+        {
+          "contract": "ERC721",
+          "path": "contracts/token/ERC721/ERC721.sol",
+          "label": "_ownedTokensCount",
+          "astId": 10516,
+          "type": "t_mapping<t_struct<Counters.Counter>>",
+          "src": "1043:63:125"
+        },
+        {
+          "contract": "ERC721",
+          "path": "contracts/token/ERC721/ERC721.sol",
+          "label": "_operatorApprovals",
+          "astId": 10522,
+          "type": "t_mapping<t_bool>",
+          "src": "1161:73:125"
+        },
+        {
+          "contract": "ERC721",
+          "path": "contracts/token/ERC721/ERC721.sol",
+          "label": "______gap",
+          "astId": 11065,
+          "type": "t_array:50<t_uint256>",
+          "src": "12696:29:125"
+        },
+        {
+          "contract": "ERC721Enumerable",
+          "path": "contracts/token/ERC721/ERC721Enumerable.sol",
+          "label": "_ownedTokens",
+          "astId": 11117,
+          "type": "t_mapping<t_array:dyn<t_uint256>>",
+          "src": "445:50:127"
+        },
+        {
+          "contract": "ERC721Enumerable",
+          "path": "contracts/token/ERC721/ERC721Enumerable.sol",
+          "label": "_ownedTokensIndex",
+          "astId": 11121,
+          "type": "t_mapping<t_uint256>",
+          "src": "565:53:127"
+        },
+        {
+          "contract": "ERC721Enumerable",
+          "path": "contracts/token/ERC721/ERC721Enumerable.sol",
+          "label": "_allTokens",
+          "astId": 11124,
+          "type": "t_array:dyn<t_uint256>",
+          "src": "679:28:127"
+        },
+        {
+          "contract": "ERC721Enumerable",
+          "path": "contracts/token/ERC721/ERC721Enumerable.sol",
+          "label": "_allTokensIndex",
+          "astId": 11128,
+          "type": "t_mapping<t_uint256>",
+          "src": "778:51:127"
+        },
+        {
+          "contract": "ERC721Enumerable",
+          "path": "contracts/token/ERC721/ERC721Enumerable.sol",
+          "label": "______gap",
+          "astId": 11459,
+          "type": "t_array:50<t_uint256>",
+          "src": "8994:29:127"
+        },
+        {
+          "contract": "ERC721Metadata",
+          "path": "contracts/token/ERC721/ERC721Metadata.sol",
+          "label": "_name",
+          "astId": 11526,
+          "type": "t_string",
+          "src": "266:20:130"
+        },
+        {
+          "contract": "ERC721Metadata",
+          "path": "contracts/token/ERC721/ERC721Metadata.sol",
+          "label": "_symbol",
+          "astId": 11528,
+          "type": "t_string",
+          "src": "313:22:130"
+        },
+        {
+          "contract": "ERC721Metadata",
+          "path": "contracts/token/ERC721/ERC721Metadata.sol",
+          "label": "_tokenURIs",
+          "astId": 11532,
+          "type": "t_mapping<t_string>",
+          "src": "381:45:130"
+        },
+        {
+          "contract": "ERC721Metadata",
+          "path": "contracts/token/ERC721/ERC721Metadata.sol",
+          "label": "______gap",
+          "astId": 11663,
+          "type": "t_array:50<t_uint256>",
+          "src": "3029:29:130"
+        },
+        {
+          "contract": "MinterRole",
+          "path": "contracts/access/roles/MinterRole.sol",
+          "label": "_minters",
+          "astId": 219,
+          "type": "t_struct<Roles.Role>",
+          "src": "271:27:2"
+        },
+        {
+          "contract": "MinterRole",
+          "path": "contracts/access/roles/MinterRole.sol",
+          "label": "______gap",
+          "astId": 319,
+          "type": "t_array:50<t_uint256>",
+          "src": "1133:29:2"
+        },
+        {
+          "contract": "ERC721MetadataMintable",
+          "path": "contracts/token/ERC721/ERC721MetadataMintable.sol",
+          "label": "______gap",
+          "astId": 11733,
+          "type": "t_array:50<t_uint256>",
+          "src": "1042:29:131"
+        },
+        {
+          "contract": "PauserRole",
+          "path": "contracts/access/roles/PauserRole.sol",
+          "label": "_pausers",
+          "astId": 339,
+          "type": "t_struct<Roles.Role>",
+          "src": "271:27:3"
+        },
+        {
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+          "path": "contracts/access/roles/PauserRole.sol",
+          "label": "______gap",
+          "astId": 439,
+          "type": "t_array:50<t_uint256>",
+          "src": "1133:29:3"
+        },
+        {
+          "contract": "Pausable",
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+          "label": "_paused",
+          "astId": 4481,
+          "type": "t_bool",
+          "src": "855:20:37"
+        },
+        {
+          "contract": "Pausable",
+          "path": "contracts/lifecycle/Pausable.sol",
+          "label": "______gap",
+          "astId": 4564,
+          "type": "t_array:50<t_uint256>",
+          "src": "2105:29:37"
+        },
+        {
+          "contract": "ERC721Pausable",
+          "path": "contracts/token/ERC721/ERC721Pausable.sol",
+          "label": "______gap",
+          "astId": 11878,
+          "type": "t_array:50<t_uint256>",
+          "src": "850:29:133"
+        }
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+        "hasSelfDestruct": false,
+        "hasDelegateCall": false,
+        "hasInitialValuesInDeclarations": false,
+        "uninitializedBaseContracts": [],
+        "storageUncheckedVars": [
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+            "path": "contracts/token/ERC721/ERC721.sol",
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+            "type": "t_mapping<t_struct<Counters.Counter>>",
+            "src": "1043:63:125"
+          },
+          {
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+            "path": "contracts/access/roles/MinterRole.sol",
+            "label": "_minters",
+            "astId": 219,
+            "type": "t_struct<Roles.Role>",
+            "src": "271:27:2"
+          },
+          {
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+            "path": "contracts/access/roles/PauserRole.sol",
+            "label": "_pausers",
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+            "type": "t_struct<Roles.Role>",
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+        ],
+        "storageDiff": [
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+            "action": "typechange",
+            "updated": {
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+              "contract": "ERC721",
+              "path": "contracts/token/ERC721/ERC721.sol",
+              "label": "_ownedTokensCount",
+              "astId": 10516,
+              "type": "t_mapping<t_struct<Counters.Counter>>",
+              "src": "1043:63:125"
+            },
+            "original": {
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+              "contract": "ERC721",
+              "path": "contracts/token/ERC721/ERC721.sol",
+              "label": "_ownedTokensCount",
+              "astId": 9505,
+              "type": "t_mapping<t_uint256>",
+              "src": "988:54:120"
+            }
+          }
+        ]
+      }
+    }
+  },
+  "solidityLibs": {},
+  "proxies": {},
+  "manifestVersion": "2.2",
+  "frozen": true,
+  "app": {
+    "address": "0x291439e6444daec9e47ae359aa79fd1811a42679"
+  },
+  "package": {
+    "address": "0xa44bb80b290de8a465d17b14269df53cf0b9bf4f"
+  },
+  "provider": {
+    "address": "0x20b96704e5cab368fc05d8729b9d2c4c830f9338"
+  },
+  "version": "2.2.0"
+}

.openzeppelin/ropsten.json

@@ -0,0 +1,851 @@
+{
+  "contracts": {
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+      "address": "0x37b52342e1e8eca924c69e49797e8b1a80251a88",
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+      "deployedBytecodeHash": "94b5eed89a6bab268326a5010e52000ff74d40d96c83811c9d455d7c8b54f447",
+      "types": {
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+          "kind": "mapping"
+        },
+        "t_mapping<t_bool>": {
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+          "valueType": "t_bool",
+          "label": "mapping(key => bool)",
+          "kind": "mapping"
+        }
+      },
+      "storage": [
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+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "initialized",
+          "astId": 13503,
+          "type": "t_bool",
+          "src": "757:24:147"
+        },
+        {
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+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "initializing",
+          "astId": 13505,
+          "type": "t_bool",
+          "src": "876:25:147"
+        },
+        {
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+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "______gap",
+          "astId": 13554,
+          "type": "t_array:50<t_uint256>",
+          "src": "1891:29:147"
+        },
+        {
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+          "path": "contracts/ownership/Ownable.sol",
+          "label": "_owner",
+          "astId": 8198,
+          "type": "t_address",
+          "src": "472:22:108"
+        },
+        {
+          "contract": "Ownable",
+          "path": "contracts/ownership/Ownable.sol",
+          "label": "______gap",
+          "astId": 8311,
+          "type": "t_array:50<t_uint256>",
+          "src": "2415:29:108"
+        },
+        {
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+          "label": "_beneficiary",
+          "astId": 3576,
+          "type": "t_address",
+          "src": "1133:28:28"
+        },
+        {
+          "contract": "TokenVesting",
+          "path": "contracts/drafts/TokenVesting.sol",
+          "label": "_cliff",
+          "astId": 3578,
+          "type": "t_uint256",
+          "src": "1263:22:28"
+        },
+        {
+          "contract": "TokenVesting",
+          "path": "contracts/drafts/TokenVesting.sol",
+          "label": "_start",
+          "astId": 3580,
+          "type": "t_uint256",
+          "src": "1291:22:28"
+        },
+        {
+          "contract": "TokenVesting",
+          "path": "contracts/drafts/TokenVesting.sol",
+          "label": "_duration",
+          "astId": 3582,
+          "type": "t_uint256",
+          "src": "1319:25:28"
+        },
+        {
+          "contract": "TokenVesting",
+          "path": "contracts/drafts/TokenVesting.sol",
+          "label": "_revocable",
+          "astId": 3584,
+          "type": "t_bool",
+          "src": "1351:23:28"
+        },
+        {
+          "contract": "TokenVesting",
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+          "label": "_released",
+          "astId": 3588,
+          "type": "t_mapping<t_uint256>",
+          "src": "1381:46:28"
+        },
+        {
+          "contract": "TokenVesting",
+          "path": "contracts/drafts/TokenVesting.sol",
+          "label": "_revoked",
+          "astId": 3592,
+          "type": "t_mapping<t_bool>",
+          "src": "1433:42:28"
+        },
+        {
+          "contract": "TokenVesting",
+          "path": "contracts/drafts/TokenVesting.sol",
+          "label": "______gap",
+          "astId": 3941,
+          "type": "t_array:50<t_uint256>",
+          "src": "6226:29:28"
+        }
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+        "hasSelfDestruct": false,
+        "hasDelegateCall": false,
+        "hasInitialValuesInDeclarations": false,
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+      "types": {
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+          "valueType": "t_address",
+          "length": "dyn",
+          "kind": "array",
+          "label": "address[]"
+        }
+      },
+      "storage": [
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+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "initialized",
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+          "type": "t_bool",
+          "src": "757:24:147"
+        },
+        {
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+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "initializing",
+          "astId": 13505,
+          "type": "t_bool",
+          "src": "876:25:147"
+        },
+        {
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+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "______gap",
+          "astId": 13554,
+          "type": "t_array:50<t_uint256>",
+          "src": "1891:29:147"
+        },
+        {
+          "contract": "PaymentSplitter",
+          "path": "contracts/payment/PaymentSplitter.sol",
+          "label": "_totalShares",
+          "astId": 8418,
+          "type": "t_uint256",
+          "src": "1176:28:110"
+        },
+        {
+          "contract": "PaymentSplitter",
+          "path": "contracts/payment/PaymentSplitter.sol",
+          "label": "_totalReleased",
+          "astId": 8420,
+          "type": "t_uint256",
+          "src": "1210:30:110"
+        },
+        {
+          "contract": "PaymentSplitter",
+          "path": "contracts/payment/PaymentSplitter.sol",
+          "label": "_shares",
+          "astId": 8424,
+          "type": "t_mapping<t_uint256>",
+          "src": "1247:43:110"
+        },
+        {
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+          "label": "_released",
+          "astId": 8428,
+          "type": "t_mapping<t_uint256>",
+          "src": "1296:45:110"
+        },
+        {
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+          "path": "contracts/payment/PaymentSplitter.sol",
+          "label": "_payees",
+          "astId": 8431,
+          "type": "t_array:dyn<t_address>",
+          "src": "1347:25:110"
+        },
+        {
+          "contract": "PaymentSplitter",
+          "path": "contracts/payment/PaymentSplitter.sol",
+          "label": "______gap",
+          "astId": 8684,
+          "type": "t_array:50<t_uint256>",
+          "src": "5158:29:110"
+        }
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+        "hasSelfDestruct": false,
+        "hasDelegateCall": false,
+        "hasInitialValuesInDeclarations": false,
+        "uninitializedBaseContracts": []
+      }
+    },
+    "StandaloneERC20": {
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+      "constructorCode": "608060405234801561001057600080fd5b50613153806100206000396000f3fe",
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+        },
+        "t_struct<Roles.Role>": {
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+          "kind": "struct",
+          "label": "Roles.Role",
+          "members": [
+            {
+              "label": "bearer",
+              "astId": 5,
+              "type": "t_mapping<t_bool>",
+              "src": "150:32:0"
+            }
+          ]
+        },
+        "t_mapping<t_bool>": {
+          "id": "t_mapping<t_bool>",
+          "valueType": "t_bool",
+          "label": "mapping(key => bool)",
+          "kind": "mapping"
+        }
+      },
+      "storage": [
+        {
+          "contract": "Initializable",
+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "initialized",
+          "astId": 13503,
+          "type": "t_bool",
+          "src": "757:24:147"
+        },
+        {
+          "contract": "Initializable",
+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "initializing",
+          "astId": 13505,
+          "type": "t_bool",
+          "src": "876:25:147"
+        },
+        {
+          "contract": "Initializable",
+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "______gap",
+          "astId": 13554,
+          "type": "t_array:50<t_uint256>",
+          "src": "1891:29:147"
+        },
+        {
+          "contract": "ERC20Detailed",
+          "path": "contracts/token/ERC20/ERC20Detailed.sol",
+          "label": "_name",
+          "astId": 9641,
+          "type": "t_string",
+          "src": "209:20:118"
+        },
+        {
+          "contract": "ERC20Detailed",
+          "path": "contracts/token/ERC20/ERC20Detailed.sol",
+          "label": "_symbol",
+          "astId": 9643,
+          "type": "t_string",
+          "src": "235:22:118"
+        },
+        {
+          "contract": "ERC20Detailed",
+          "path": "contracts/token/ERC20/ERC20Detailed.sol",
+          "label": "_decimals",
+          "astId": 9645,
+          "type": "t_uint8",
+          "src": "263:23:118"
+        },
+        {
+          "contract": "ERC20Detailed",
+          "path": "contracts/token/ERC20/ERC20Detailed.sol",
+          "label": "______gap",
+          "astId": 9697,
+          "type": "t_array:50<t_uint256>",
+          "src": "1645:29:118"
+        },
+        {
+          "contract": "ERC20",
+          "path": "contracts/token/ERC20/ERC20.sol",
+          "label": "_balances",
+          "astId": 9129,
+          "type": "t_mapping<t_uint256>",
+          "src": "1357:46:115"
+        },
+        {
+          "contract": "ERC20",
+          "path": "contracts/token/ERC20/ERC20.sol",
+          "label": "_allowances",
+          "astId": 9135,
+          "type": "t_mapping<t_uint256>",
+          "src": "1410:69:115"
+        },
+        {
+          "contract": "ERC20",
+          "path": "contracts/token/ERC20/ERC20.sol",
+          "label": "_totalSupply",
+          "astId": 9137,
+          "type": "t_uint256",
+          "src": "1486:28:115"
+        },
+        {
+          "contract": "ERC20",
+          "path": "contracts/token/ERC20/ERC20.sol",
+          "label": "______gap",
+          "astId": 9516,
+          "type": "t_array:50<t_uint256>",
+          "src": "7875:29:115"
+        },
+        {
+          "contract": "MinterRole",
+          "path": "contracts/access/roles/MinterRole.sol",
+          "label": "_minters",
+          "astId": 219,
+          "type": "t_struct<Roles.Role>",
+          "src": "271:27:2"
+        },
+        {
+          "contract": "MinterRole",
+          "path": "contracts/access/roles/MinterRole.sol",
+          "label": "______gap",
+          "astId": 319,
+          "type": "t_array:50<t_uint256>",
+          "src": "1133:29:2"
+        },
+        {
+          "contract": "ERC20Mintable",
+          "path": "contracts/token/ERC20/ERC20Mintable.sol",
+          "label": "______gap",
+          "astId": 9746,
+          "type": "t_array:50<t_uint256>",
+          "src": "816:29:119"
+        },
+        {
+          "contract": "PauserRole",
+          "path": "contracts/access/roles/PauserRole.sol",
+          "label": "_pausers",
+          "astId": 339,
+          "type": "t_struct<Roles.Role>",
+          "src": "271:27:3"
+        },
+        {
+          "contract": "PauserRole",
+          "path": "contracts/access/roles/PauserRole.sol",
+          "label": "______gap",
+          "astId": 439,
+          "type": "t_array:50<t_uint256>",
+          "src": "1133:29:3"
+        },
+        {
+          "contract": "Pausable",
+          "path": "contracts/lifecycle/Pausable.sol",
+          "label": "_paused",
+          "astId": 4481,
+          "type": "t_bool",
+          "src": "855:20:37"
+        },
+        {
+          "contract": "Pausable",
+          "path": "contracts/lifecycle/Pausable.sol",
+          "label": "______gap",
+          "astId": 4564,
+          "type": "t_array:50<t_uint256>",
+          "src": "2105:29:37"
+        },
+        {
+          "contract": "ERC20Pausable",
+          "path": "contracts/token/ERC20/ERC20Pausable.sol",
+          "label": "______gap",
+          "astId": 9869,
+          "type": "t_array:50<t_uint256>",
+          "src": "1178:29:120"
+        }
+      ],
+      "warnings": {
+        "hasConstructor": false,
+        "hasSelfDestruct": false,
+        "hasDelegateCall": false,
+        "hasInitialValuesInDeclarations": false,
+        "uninitializedBaseContracts": []
+      }
+    },
+    "StandaloneERC721": {
+      "address": "0xf43fe8b882b9821b3d648fb9f4d99d2fd736368c",
+      "constructorCode": "608060405234801561001057600080fd5b50614299806100206000396000f3fe",
+      "bodyBytecodeHash": "9113153cb4b2b62f720cb12960ba3b4a7b9a5f3329e34a4a3ece0212d130ae53",
+      "localBytecodeHash": "5dca693db1fee9a4ce973e49d6665a8770b823c36ba2c7e64f37d81046672074",
+      "deployedBytecodeHash": "5dca693db1fee9a4ce973e49d6665a8770b823c36ba2c7e64f37d81046672074",
+      "types": {
+        "t_bool": {
+          "id": "t_bool",
+          "kind": "elementary",
+          "label": "bool"
+        },
+        "t_uint256": {
+          "id": "t_uint256",
+          "kind": "elementary",
+          "label": "uint256"
+        },
+        "t_array:50<t_uint256>": {
+          "id": "t_array:50<t_uint256>",
+          "valueType": "t_uint256",
+          "length": "50",
+          "kind": "array",
+          "label": "uint256[50]"
+        },
+        "t_mapping<t_bool>": {
+          "id": "t_mapping<t_bool>",
+          "valueType": "t_bool",
+          "label": "mapping(key => bool)",
+          "kind": "mapping"
+        },
+        "t_address": {
+          "id": "t_address",
+          "kind": "elementary",
+          "label": "address"
+        },
+        "t_mapping<t_address>": {
+          "id": "t_mapping<t_address>",
+          "valueType": "t_address",
+          "label": "mapping(key => address)",
+          "kind": "mapping"
+        },
+        "t_struct<Counters.Counter>": {
+          "id": "t_struct<Counters.Counter>",
+          "kind": "struct",
+          "label": "Counters.Counter",
+          "members": [
+            {
+              "label": "_value",
+              "astId": 2533,
+              "type": "t_uint256",
+              "src": "1022:14:22"
+            }
+          ]
+        },
+        "t_mapping<t_struct<Counters.Counter>>": {
+          "id": "t_mapping<t_struct<Counters.Counter>>",
+          "valueType": "t_struct<Counters.Counter>",
+          "label": "mapping(key => Counters.Counter)",
+          "kind": "mapping"
+        },
+        "t_array:dyn<t_uint256>": {
+          "id": "t_array:dyn<t_uint256>",
+          "valueType": "t_uint256",
+          "length": "dyn",
+          "kind": "array",
+          "label": "uint256[]"
+        },
+        "t_mapping<t_array:dyn<t_uint256>>": {
+          "id": "t_mapping<t_array:dyn<t_uint256>>",
+          "valueType": "t_array:dyn<t_uint256>",
+          "label": "mapping(key => uint256[])",
+          "kind": "mapping"
+        },
+        "t_mapping<t_uint256>": {
+          "id": "t_mapping<t_uint256>",
+          "valueType": "t_uint256",
+          "label": "mapping(key => uint256)",
+          "kind": "mapping"
+        },
+        "t_string": {
+          "id": "t_string",
+          "kind": "elementary",
+          "label": "string"
+        },
+        "t_mapping<t_string>": {
+          "id": "t_mapping<t_string>",
+          "valueType": "t_string",
+          "label": "mapping(key => string)",
+          "kind": "mapping"
+        },
+        "t_struct<Roles.Role>": {
+          "id": "t_struct<Roles.Role>",
+          "kind": "struct",
+          "label": "Roles.Role",
+          "members": [
+            {
+              "label": "bearer",
+              "astId": 5,
+              "type": "t_mapping<t_bool>",
+              "src": "150:32:0"
+            }
+          ]
+        }
+      },
+      "storage": [
+        {
+          "contract": "Initializable",
+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "initialized",
+          "astId": 13503,
+          "type": "t_bool",
+          "src": "757:24:147"
+        },
+        {
+          "contract": "Initializable",
+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "initializing",
+          "astId": 13505,
+          "type": "t_bool",
+          "src": "876:25:147"
+        },
+        {
+          "contract": "Initializable",
+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "______gap",
+          "astId": 13554,
+          "type": "t_array:50<t_uint256>",
+          "src": "1891:29:147"
+        },
+        {
+          "contract": "ERC165",
+          "path": "contracts/introspection/ERC165.sol",
+          "label": "_supportedInterfaces",
+          "astId": 4117,
+          "type": "t_mapping<t_bool>",
+          "src": "550:52:31"
+        },
+        {
+          "contract": "ERC165",
+          "path": "contracts/introspection/ERC165.sol",
+          "label": "______gap",
+          "astId": 4162,
+          "type": "t_array:50<t_uint256>",
+          "src": "1714:29:31"
+        },
+        {
+          "contract": "ERC721",
+          "path": "contracts/token/ERC721/ERC721.sol",
+          "label": "_tokenOwner",
+          "astId": 10508,
+          "type": "t_mapping<t_address>",
+          "src": "829:48:125"
+        },
+        {
+          "contract": "ERC721",
+          "path": "contracts/token/ERC721/ERC721.sol",
+          "label": "_tokenApprovals",
+          "astId": 10512,
+          "type": "t_mapping<t_address>",
+          "src": "933:52:125"
+        },
+        {
+          "contract": "ERC721",
+          "path": "contracts/token/ERC721/ERC721.sol",
+          "label": "_ownedTokensCount",
+          "astId": 10516,
+          "type": "t_mapping<t_struct<Counters.Counter>>",
+          "src": "1043:63:125"
+        },
+        {
+          "contract": "ERC721",
+          "path": "contracts/token/ERC721/ERC721.sol",
+          "label": "_operatorApprovals",
+          "astId": 10522,
+          "type": "t_mapping<t_bool>",
+          "src": "1161:73:125"
+        },
+        {
+          "contract": "ERC721",
+          "path": "contracts/token/ERC721/ERC721.sol",
+          "label": "______gap",
+          "astId": 11065,
+          "type": "t_array:50<t_uint256>",
+          "src": "12696:29:125"
+        },
+        {
+          "contract": "ERC721Enumerable",
+          "path": "contracts/token/ERC721/ERC721Enumerable.sol",
+          "label": "_ownedTokens",
+          "astId": 11117,
+          "type": "t_mapping<t_array:dyn<t_uint256>>",
+          "src": "445:50:127"
+        },
+        {
+          "contract": "ERC721Enumerable",
+          "path": "contracts/token/ERC721/ERC721Enumerable.sol",
+          "label": "_ownedTokensIndex",
+          "astId": 11121,
+          "type": "t_mapping<t_uint256>",
+          "src": "565:53:127"
+        },
+        {
+          "contract": "ERC721Enumerable",
+          "path": "contracts/token/ERC721/ERC721Enumerable.sol",
+          "label": "_allTokens",
+          "astId": 11124,
+          "type": "t_array:dyn<t_uint256>",
+          "src": "679:28:127"
+        },
+        {
+          "contract": "ERC721Enumerable",
+          "path": "contracts/token/ERC721/ERC721Enumerable.sol",
+          "label": "_allTokensIndex",
+          "astId": 11128,
+          "type": "t_mapping<t_uint256>",
+          "src": "778:51:127"
+        },
+        {
+          "contract": "ERC721Enumerable",
+          "path": "contracts/token/ERC721/ERC721Enumerable.sol",
+          "label": "______gap",
+          "astId": 11459,
+          "type": "t_array:50<t_uint256>",
+          "src": "8994:29:127"
+        },
+        {
+          "contract": "ERC721Metadata",
+          "path": "contracts/token/ERC721/ERC721Metadata.sol",
+          "label": "_name",
+          "astId": 11526,
+          "type": "t_string",
+          "src": "266:20:130"
+        },
+        {
+          "contract": "ERC721Metadata",
+          "path": "contracts/token/ERC721/ERC721Metadata.sol",
+          "label": "_symbol",
+          "astId": 11528,
+          "type": "t_string",
+          "src": "313:22:130"
+        },
+        {
+          "contract": "ERC721Metadata",
+          "path": "contracts/token/ERC721/ERC721Metadata.sol",
+          "label": "_tokenURIs",
+          "astId": 11532,
+          "type": "t_mapping<t_string>",
+          "src": "381:45:130"
+        },
+        {
+          "contract": "ERC721Metadata",
+          "path": "contracts/token/ERC721/ERC721Metadata.sol",
+          "label": "______gap",
+          "astId": 11663,
+          "type": "t_array:50<t_uint256>",
+          "src": "3029:29:130"
+        },
+        {
+          "contract": "MinterRole",
+          "path": "contracts/access/roles/MinterRole.sol",
+          "label": "_minters",
+          "astId": 219,
+          "type": "t_struct<Roles.Role>",
+          "src": "271:27:2"
+        },
+        {
+          "contract": "MinterRole",
+          "path": "contracts/access/roles/MinterRole.sol",
+          "label": "______gap",
+          "astId": 319,
+          "type": "t_array:50<t_uint256>",
+          "src": "1133:29:2"
+        },
+        {
+          "contract": "ERC721MetadataMintable",
+          "path": "contracts/token/ERC721/ERC721MetadataMintable.sol",
+          "label": "______gap",
+          "astId": 11733,
+          "type": "t_array:50<t_uint256>",
+          "src": "1042:29:131"
+        },
+        {
+          "contract": "PauserRole",
+          "path": "contracts/access/roles/PauserRole.sol",
+          "label": "_pausers",
+          "astId": 339,
+          "type": "t_struct<Roles.Role>",
+          "src": "271:27:3"
+        },
+        {
+          "contract": "PauserRole",
+          "path": "contracts/access/roles/PauserRole.sol",
+          "label": "______gap",
+          "astId": 439,
+          "type": "t_array:50<t_uint256>",
+          "src": "1133:29:3"
+        },
+        {
+          "contract": "Pausable",
+          "path": "contracts/lifecycle/Pausable.sol",
+          "label": "_paused",
+          "astId": 4481,
+          "type": "t_bool",
+          "src": "855:20:37"
+        },
+        {
+          "contract": "Pausable",
+          "path": "contracts/lifecycle/Pausable.sol",
+          "label": "______gap",
+          "astId": 4564,
+          "type": "t_array:50<t_uint256>",
+          "src": "2105:29:37"
+        },
+        {
+          "contract": "ERC721Pausable",
+          "path": "contracts/token/ERC721/ERC721Pausable.sol",
+          "label": "______gap",
+          "astId": 11878,
+          "type": "t_array:50<t_uint256>",
+          "src": "850:29:133"
+        }
+      ],
+      "warnings": {
+        "hasConstructor": false,
+        "hasSelfDestruct": false,
+        "hasDelegateCall": false,
+        "hasInitialValuesInDeclarations": false,
+        "uninitializedBaseContracts": []
+      }
+    }
+  },
+  "solidityLibs": {},
+  "proxies": {},
+  "manifestVersion": "2.2",
+  "frozen": true,
+  "app": {
+    "address": "0x27a09abca2c4d9f914dbc7bea164b0e6b74ce7a9"
+  },
+  "package": {
+    "address": "0x2a9e7b63514438906a83a1e320dbbd814d417002"
+  },
+  "provider": {
+    "address": "0xb818f726ea886a73dc4105252f0e7c10b6309cae"
+  },
+  "version": "2.2.0"
+}

.solhint.json

@@ -0,0 +1,11 @@
+{
+  "extends": "default",
+  "rules": {
+    "indent": ["error", 4],
+
+    "bracket-align": false,
+    "compiler-fixed": false,
+    "no-simple-event-func-name": false,
+    "two-lines-top-level-separator": false
+  }
+}

.soliumignore

@@ -1 +0,0 @@
-node_modules

.soliumrc.json

@@ -1,21 +0,0 @@
-{
-  "extends": "solium:all",
-  "plugins": ["security"],
-  "rules": {
-    "blank-lines": "off",
-    "error-reason": "off",
-    "indentation": ["error", 2],
-    "lbrace": "off",
-    "linebreak-style": ["error", "unix"],
-    "max-len": ["error", 79],
-    "no-constant": ["error"],
-    "no-empty-blocks": "off",
-    "quotes": ["error", "double"],
-    "uppercase": "off",
-    "visibility-first": "error",
-
-    "security/enforce-explicit-visibility": ["error"],
-    "security/no-block-members": ["warning"],
-    "security/no-inline-assembly": ["warning"]
-  }
-}

.travis.yml

@@ -15,29 +15,26 @@ jobs:
   # --elopio - 20180531
   fast_finish: true
   allow_failures:
-    - env: SOLIDITY_COVERAGE=true
     - env: SOLC_NIGHTLY=true
   include:
-    # Run the unit test suite three times in parallel.
-    # The first one gets results faster and is the only one required to pass.
-    # The second one generates the coverage report.
-    # The third one is to keep us informed about possible issues with the
-    # upcoming solidity release.
     - stage: tests
-      name: "unit tests"
+      name: "Linter"
+      script: npm run lint
+
+    - stage: tests
+      name: "Unit tests"
       script: npm run test
+
     - stage: tests
-      name: "unit tests with coverage"
+      name: "Unit tests with coverage report"
       script: npm run test
       env: SOLIDITY_COVERAGE=true
+
     - stage: tests
-      name: "unit tests with solc nightly"
+      name: "Unit tests using solc nightly"
       script: npm run test
       env: SOLC_NIGHTLY=true
-    # solidity and javascript style tests.
-    - stage: tests
-      name: "static tests"
-      script: npm run lint
+
     - stage: update docs
       if: tag =~ ^v[0-9]+\.[0-9]+\.[0-9]+$
       addons:

CHANGELOG.md

@@ -0,0 +1,65 @@
+# Changelog
+
+## 2.2.1 (2019-07-22)
+
+### Changes:
+* Renamed package to `@openzeppelin/contracts-ethereum-package`. ([#54](https://github.com/OpenZeppelin/openzeppelin-contracts-ethereum-package/pull/54))
+
+## 2.2.0 (2019-03-14)
+
+### New features:
+ * `ERC20Snapshot`: create snapshots on demand of the token balances and total supply, to later retrieve and e.g. calculate dividends at a past time. ([#1617](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1617))
+ * `SafeERC20`: `ERC20` contracts with no return value (i.e. that revert on failure) are now supported. ([#1655](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/))
+ * `ERC20`: added internal `_approve(address owner, address spender, uint256 value)`, allowing derived contracts to set the allowance of arbitrary accounts. ([#1609](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1609))
+ * `ERC20Metadata`: added internal `_setTokenURI(string memory tokenURI)`. ([#1618](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1618))
+ * `TimedCrowdsale`: added internal `_extendTime(uint256 newClosingTime)` as well as `TimedCrowdsaleExtended(uint256 prevClosingTime, uint256 newClosingTime)` event allowing to extend the crowdsale, as long as it hasn't already closed.
+
+### Improvements:
+ * Upgraded the minimum compiler version to v0.5.2: this removes many Solidity warnings that were false positives. ([#1606](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1606))
+ * `ECDSA`: `recover` no longer accepts malleable signatures (those using upper-range values for `s`, or 0/1 for `v`). ([#1622](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1622))
+ * `ERC721`'s transfers are now more gas efficient due to removal of unnecessary `SafeMath` calls. ([#1610](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1610))
+ * `Counter`'s API has been improved, and is now used by `ERC721` (though it is still in `drafts`). ([#1610](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1610))
+ * Fixed variable shadowing issues. ([#1606](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1606))
+
+### Bugfixes:
+ * (minor) `SafeERC20`: `safeApprove` wasn't properly checking for a zero allowance when attempting to set a non-zero allowance. ([#1647](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1647))
+
+### Breaking changes:
+ * `TokenMetadata` (in drafts) has been renamed to `ERC20Metadata`. ([#1618](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1618))
+
+## 2.1.3 (2019-02-26)
+ * Backported `SafeERC20.safeApprove` bugfix. ([#1647](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1647))
+
+## 2.1.2 (2019-01-17)
+ * Removed most of the test suite from the npm package, except `PublicRole.behavior.js`, which may be useful to users testing their own `Roles`.
+
+## 2.1.1 (2019-01-04)
+ * Version bump to avoid conflict in the npm registry.
+
+## 2.1.0 (2019-01-04)
+
+### New features:
+ * Now targeting the 0.5.x line of Solidity compilers. For 0.4.24 support, use version 2.0 of OpenZeppelin.
+ * `WhitelistCrowdsale`: a crowdsale where only whitelisted accounts (`WhitelistedRole`) can purchase tokens. Adding or removing accounts from the whitelist is done by whitelist admins (`WhitelistAdminRole`). Similar to the pre-2.0 `WhitelistedCrowdsale`. ([#1525](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1525), [#1589](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1589))
+ * `RefundablePostDeliveryCrowdsale`: replacement for `RefundableCrowdsale` (deprecated, see below) where tokens are only granted once the crowdsale ends (if it meets its goal). ([#1543](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1543))
+ * `PausableCrowdsale`: allows for pausers (`PauserRole`) to pause token purchases. Other crowdsale operations (e.g. withdrawals and refunds, if applicable) are not affected. ([#832](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/832))
+ * `ERC20`: `transferFrom` and `_burnFrom ` now emit `Approval` events, to represent the token's state comprehensively through events. ([#1524](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1524))
+ * `ERC721`: added `_burn(uint256 tokenId)`, replacing the similar deprecated function (see below). ([#1550](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1550))
+ * `ERC721`: added `_tokensOfOwner(address owner)`, allowing to internally retrieve the array of an account's owned tokens. ([#1522](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1522))
+ * Crowdsales: all constructors are now `public`, meaning it is not necessary to extend these contracts in order to deploy them. The exception is `FinalizableCrowdsale`, since it is meaningless unless extended. ([#1564](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1564))
+ * `SignedSafeMath`: added overflow-safe operations for signed integers (`int256`). ([#1559](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1559), [#1588](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1588))
+
+### Improvements:
+ * The compiler version required by `Array` was behind the rest of the libray so it was updated to `v0.4.24`. ([#1553](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1553))
+ * Now conforming to a 4-space indentation code style. ([1508](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1508))
+ * `ERC20`: more gas efficient due to removed redundant `require`s. ([#1409](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1409))
+ * `ERC721`: fixed a bug that prevented internal data structures from being properly cleaned, missing potential gas refunds. ([#1539](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1539) and [#1549](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1549))
+ * `ERC721`: general gas savings on `transferFrom`, `_mint` and `_burn`, due to redudant `require`s and `SSTORE`s. ([#1549](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1549))
+
+### Bugfixes:
+
+### Breaking changes:
+
+### Deprecations:
+ * `ERC721._burn(address owner, uint256 tokenId)`: due to the `owner` parameter being unnecessary. ([#1550](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1550))
+ * `RefundableCrowdsale`: due to trading abuse potential on crowdsales that miss their goal. ([#1543](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1543))

README.md

@@ -1,42 +1,100 @@
 # <img src="logo.png" alt="OpenZeppelin" width="400px">
 
-[![NPM Package](https://img.shields.io/npm/v/openzeppelin-solidity.svg?style=flat-square)](https://www.npmjs.org/package/openzeppelin-solidity)
-[![Build Status](https://img.shields.io/travis/OpenZeppelin/openzeppelin-solidity.svg?branch=master&style=flat-square)](https://travis-ci.org/OpenZeppelin/openzeppelin-solidity)
-[![Coverage Status](https://img.shields.io/coveralls/github/OpenZeppelin/openzeppelin-solidity/master.svg?style=flat-square)](https://coveralls.io/github/OpenZeppelin/openzeppelin-solidity?branch=master)
+# OpenZeppelin Contracts Ethereum Package
 
-**OpenZeppelin is a library for secure smart contract development.** It provides implementations of standards like ERC20 and ERC721 which you can deploy as-is or extend to suit your needs, as well as Solidity components to build custom contracts and more complex decentralized systems.
+[![NPM Package](https://img.shields.io/npm/v/openzeppelin-contracts-ethereum-package.svg?style=flat-square)](https://www.npmjs.org/package/@openzeppelin/contracts-ethereum-package)
+[![Build Status](https://img.shields.io/travis/OpenZeppelin/openzeppelin-contracts-ethereum-package.svg?branch=master&style=flat-square)](https://travis-ci.org/OpenZeppelin/openzeppelin-contracts-ethereum-package)
+
+**OpenZeppelin Contracts is a library for secure smart contract development.** It provides implementations of standards like ERC20 and ERC721 which you can deploy as-is or extend to suit your needs, as well as Solidity components to build custom contracts and more complex decentralized systems.
+
+This fork of OpenZeppelin is set up as a **reusable Ethereum Package**. It is deployed to the kovan, rinkeby, and ropsten test networks, as well as to the main Ethereum network. You can reuse any of the pre-deployed on-chain contracts by simply linking to them using the [OpenZeppelin SDK](https://github.com/openzeppelin/openzeppelin-sdk), or reuse their Solidity source code as with the [vanilla version of OpenZeppelin Contracts](https://github.com/OpenZeppelin/openzeppelin-contracts).
+
+## Differences with openzeppelin-contracts
+
+This package contains the same contracts as the vanilla [openzeppelin-contracts](https://github.com/openZeppelin/openzeppelin-contracts). The main difference is that _all contracts in this package are potentially upgradeable_: you will notice that no contracts have constructors defined, but use [initializer functions](https://docs.zeppelinos.org/docs/writing_contracts.html#initializers) instead. Also, this package is set up as an Ethereum package, and provides a small set of pre-deployed logic contracts that can be used directly via the OpenZeppelin SDK, without needing to deploy them again.
+
+All in all, **you should use this package instead of openzeppelin-solidity if you are managing your project via the OpenZeppelin CLI**.
 
 ## Install
 
 ```
-npm install openzeppelin-solidity
+npm install @openzeppelin/contracts-ethereum-package
 ```
 
-## Usage
+## Deployed logic contracts
 
-To write your custom contracts, import ours and extend them through inheritance.
+- [StandaloneERC20](contracts/token/ERC20/StandaloneERC20.sol): ERC20 token implementation, optionally mintable and pausable.
+- [StandaloneERC721](contracts/token/ERC721/StandaloneERC721.sol): ERC721 non-fungible token implementation with metadata and enumerable extensions, optionally mintable and pausable.
+- [TokenVesting](contracts/drafts/TokenVesting.sol): tToken holder contract that can release its token balance gradually like a typical vesting scheme, with a cliff and vesting period, optionally revocable.
+- [PaymentSplitter](contracts/payment/PaymentSplitter.sol): Splits payments among a group of addresses proportionately to some number of shares they own.
+
+## Using via the OpenZeppelin CLI
+
+You can easily create upgradeable instances of any of the logic contracts listed above using the OpenZeppelin CLI. This will rely on the pre-deployed instances in mainnet, kovan, ropsten, or rinkeby, greatly reducing your gas deployment costs. To do this, just [create a new OpenZeppelin SDK project](https://docs.zeppelinos.org/docs/deploying.html) and [link to this package](https://docs.zeppelinos.org/docs/linking.html).
+
+```bash
+$ npm install -g @openzeppelin/cli
+$ openzeppelin init
+$ openzeppelin link @openzeppelin/contracts-ethereum-package
+> Installing...
+$ openzeppelin create @openzeppelin/contracts-ethereum-package/StandaloneERC20
+> Creating...
+```
+
+To create an instance of a contract, use the `openzeppelin create` command. As an example, you can run the following to create an upgradeable ERC20 named MyToken, with symbol TKN and 8 decimals, and an initial supply of 100 tokens assigned to the address HOLDER, with a MINTER and a PAUSER. Remember to replace $HOLDER, $MINTER, and $PAUSER with actual addresses when you run this command; you can specify more than one (or none at all) minters and pausers.
+
+```
+$ openzeppelin create
+? Pick a contract to instantiate: @openzeppelin/contracts-ethereum-package/StandaloneERC20
+? Pick a network: development
+✓ Deploying @openzeppelin/contracts-ethereum-package dependency to network
+? Do you want to call a function on the instance after creating it?: Yes
+? Select which function: * initialize(name: string, symbol: string, decimals: uint8, initialSupply: uint256, initialHolder: address, minters: address[], pausers: address[])
+? name (string): MyToken
+? symbol (string): MYT
+? decimals (uint8): 18
+? initialSupply (uint256): 100e18
+? initialHolder (address): 0x90f8bf6a479f320ead074411a4b0e7944ea8c9c1
+? minters (address[]): 
+? pausers (address[]): 
+✓ Setting everything up to create contract instances
+✓ Instance created at 0x2612Af3A521c2df9EAF28422Ca335b04AdF3ac66
+```
+
+OpenZeppelin will create an upgradeable ERC20 instance and keep track of its address in the `.openzeppelin/rinkeby.json` file. Should you update your version of the openzeppelin contracts ethereum package later down the road, you can simply run `openzeppelin update` to upgrade all your ERC20 instances to the latest version.
+
+You can also deploy a ERC721 token by choosing the `StandaloneERC721` contract when running `openzeppelin create`. Refer to the `initialize` function of each of the predeployed logic contracts to see which parameters are required for initialization.
+
+## Extending contracts
+
+If you prefer to write your custom contracts, import the ones from this package and extend them through inheritance. Note that **you must use this package and not `@openzeppelin/contracts` if you are [writing upgradeable contracts](https://docs.zeppelinos.org/docs/writing_contracts.html)**.
 
 ```solidity
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.0;
 
-import 'openzeppelin-solidity/contracts/token/ERC721/ERC721Full.sol';
-import 'openzeppelin-solidity/contracts/token/ERC721/ERC721Mintable.sol';
+import '@openzeppelin/upgrades/contracts/Initializable.sol';
+import '@openzeppelin/contracts-ethereum-package/contracts/token/ERC721/ERC721Full.sol';
+import '@openzeppelin/contracts-ethereum-package/contracts/token/ERC721/ERC721Mintable.sol';
 
-contract MyNFT is ERC721Full, ERC721Mintable {
-  constructor() ERC721Full("MyNFT", "MNFT") public {
+contract MyNFT is Initializable, ERC721Full, ERC721Mintable {
+  function initialize() public initializer {
+    ERC721.initialize();
+    ERC721Enumerable.initialize();
+    ERC721Metadata.initialize("MyNFT", "MNFT");
+    ERC721Mintable.initialize(msg.sender);
   }
 }
 ```
 
-> You need an ethereum development framework for the above import statements to work! Check out these guides for [Truffle] or [Embark].
-
-On our site you will find a few [guides] to learn about the diferent parts of OpenZeppelin, as well as [documentation for the API][API docs]. Keep in mind that the API docs are work in progress, and don’t hesitate to ask questions in [our Slack][Slack].
+On our site you will find a few [guides] to learn about the different parts of OpenZeppelin, as well as [documentation for the API][API docs]. Keep in mind that the API docs are work in progress, and don’t hesitate to ask questions in [our forum][forum].
 
 ## Security
 
-OpenZeppelin the project is maintained by [Zeppelin] the company, and developed following our high standards for code quality and security. OpenZeppelin is meant to provide tested and community-audited code, but please use common sense when doing anything that deals with real money! We take no responsibility for your implementation decisions and any security problems you might experience.
+OpenZeppelin Contracts is maintained by [OpenZeppelin](https://openzeppelin.com) the company, and developed following our high standards for code quality and security. OpenZeppelin Contracts is meant to provide tested and community-audited code, but please use common sense when doing anything that deals with real money! We take no responsibility for your implementation decisions and any security problems you might experience.
 
-The core development principles and strategies that OpenZeppelin is based on include: security in depth, simple and modular code, clarity-driven naming conventions, comprehensive unit testing, pre-and-post-condition sanity checks, code consistency, and regular audits.
+The core development principles and strategies that OpenZeppelin Contracts is based on include: security in depth, simple and modular code, clarity-driven naming conventions, comprehensive unit testing, pre-and-post-condition sanity checks, code consistency, and regular audits.
+
+The latest audit was done on October 2018 on version 2.0.0.
 
 Please report any security issues you find to security@openzeppelin.org.
 
@@ -48,11 +106,7 @@ OpenZeppelin exists thanks to its contributors. There are many ways you can part
 
 OpenZeppelin is released under the [MIT License](LICENSE).
 
-
-[API docs]: https://openzeppelin.org/api/docs/token_ERC721_ERC721BasicToken.html
-[guides]: https://openzeppelin.org/api/docs/get-started.html
-[Slack]: https://slack.openzeppelin.org
-[Zeppelin]: https://zeppelin.solutions
+[API docs]: https://docs.openzeppelin.org/v2.3.0/api/token/erc20
+[guides]: https://docs.openzeppelin.org/v2.3.0/get-started
+[forum]: https://forum.zeppelin.solutions
 [contribution guide]: CONTRIBUTING.md
-[Truffle]: https://truffleframework.com/docs/truffle/quickstart
-[Embark]: https://embark.status.im/docs/quick_start.html

RELEASING.md

@@ -34,7 +34,7 @@ git push upstream vX.Y.Z-rc.R
 
 Draft the release notes in our [GitHub releases](https://github.com/OpenZeppelin/openzeppelin-solidity/releases). Make sure to mark it as a pre-release! Try to be consistent with our previous release notes in the title and format of the text. Release candidates don't need a detailed changelog, but make sure to include a link to GitHub's compare page.
 
-Once the CI run for the new tag is green, publish on npm under the `next` tag.
+Once the CI run for the new tag is green, publish on npm under the `next` tag. You should see the contracts compile automatically.
 
 ```
 npm publish --tag next
@@ -51,18 +51,21 @@ git checkout release-vX.Y.Z
 git pull upstream
 ```
 
+Before starting the release process, make one final commit to CHANGELOG.md, including the date of the release.
+
 Change the version string in `package.json`, `package-lock.json` and `ethpm.json` removing the "-rc.R" suffix. Commit these changes and tag the commit as `vX.Y.Z`.
 
 ```
 git add package.json package-lock.json ethpm.json
 git commit -m "Release vX.Y.Z"
 git tag -a vX.Y.Z
+git push upstream release-vX.Y.Z
 git push upstream vX.Y.Z
 ```
 
 Draft the release notes in GitHub releases. Try to be consistent with our previous release notes in the title and format of the text. Make sure to include a detailed changelog.
 
-Once the CI run for the new tag is green, publish on npm.
+Once the CI run for the new tag is green, publish on npm. You should see the contracts compile automatically.
 
 ```
 npm publish

contracts/access/Roles.sol

@@ -1,44 +1,40 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
 /**
  * @title Roles
  * @dev Library for managing addresses assigned to a Role.
  */
 library Roles {
-  struct Role {
-    mapping (address => bool) bearer;
-  }
+    struct Role {
+        mapping (address => bool) bearer;
+    }
 
-  /**
-   * @dev give an account access to this role
-   */
-  function add(Role storage role, address account) internal {
-    require(account != address(0));
-    require(!has(role, account));
+    /**
+     * @dev give an account access to this role
+     */
+    function add(Role storage role, address account) internal {
+        require(account != address(0));
+        require(!has(role, account));
 
-    role.bearer[account] = true;
-  }
+        role.bearer[account] = true;
+    }
 
-  /**
-   * @dev remove an account's access to this role
-   */
-  function remove(Role storage role, address account) internal {
-    require(account != address(0));
-    require(has(role, account));
+    /**
+     * @dev remove an account's access to this role
+     */
+    function remove(Role storage role, address account) internal {
+        require(account != address(0));
+        require(has(role, account));
 
-    role.bearer[account] = false;
-  }
+        role.bearer[account] = false;
+    }
 
-  /**
-   * @dev check if an account has this role
-   * @return bool
-   */
-  function has(Role storage role, address account)
-    internal
-    view
-    returns (bool)
-  {
-    require(account != address(0));
-    return role.bearer[account];
-  }
+    /**
+     * @dev check if an account has this role
+     * @return bool
+     */
+    function has(Role storage role, address account) internal view returns (bool) {
+        require(account != address(0));
+        return role.bearer[account];
+    }
 }

contracts/access/roles/CapperRole.sol

@@ -1,43 +1,49 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
 import "../Roles.sol";
 
-contract CapperRole {
-  using Roles for Roles.Role;
 
-  event CapperAdded(address indexed account);
-  event CapperRemoved(address indexed account);
+contract CapperRole is Initializable {
+    using Roles for Roles.Role;
 
-  Roles.Role private cappers;
+    event CapperAdded(address indexed account);
+    event CapperRemoved(address indexed account);
 
-  constructor() internal {
-    _addCapper(msg.sender);
-  }
+    Roles.Role private _cappers;
 
-  modifier onlyCapper() {
-    require(isCapper(msg.sender));
-    _;
-  }
+    function initialize(address sender) public initializer {
+        if (!isCapper(sender)) {
+            _addCapper(sender);
+        }
+    }
 
-  function isCapper(address account) public view returns (bool) {
-    return cappers.has(account);
-  }
+    modifier onlyCapper() {
+        require(isCapper(msg.sender));
+        _;
+    }
 
-  function addCapper(address account) public onlyCapper {
-    _addCapper(account);
-  }
+    function isCapper(address account) public view returns (bool) {
+        return _cappers.has(account);
+    }
 
-  function renounceCapper() public {
-    _removeCapper(msg.sender);
-  }
+    function addCapper(address account) public onlyCapper {
+        _addCapper(account);
+    }
 
-  function _addCapper(address account) internal {
-    cappers.add(account);
-    emit CapperAdded(account);
-  }
+    function renounceCapper() public {
+        _removeCapper(msg.sender);
+    }
 
-  function _removeCapper(address account) internal {
-    cappers.remove(account);
-    emit CapperRemoved(account);
-  }
+    function _addCapper(address account) internal {
+        _cappers.add(account);
+        emit CapperAdded(account);
+    }
+
+    function _removeCapper(address account) internal {
+        _cappers.remove(account);
+        emit CapperRemoved(account);
+    }
+
+    uint256[50] private ______gap;
 }

contracts/access/roles/MinterRole.sol

@@ -1,43 +1,49 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
 import "../Roles.sol";
 
-contract MinterRole {
-  using Roles for Roles.Role;
 
-  event MinterAdded(address indexed account);
-  event MinterRemoved(address indexed account);
+contract MinterRole is Initializable {
+    using Roles for Roles.Role;
 
-  Roles.Role private minters;
+    event MinterAdded(address indexed account);
+    event MinterRemoved(address indexed account);
 
-  constructor() internal {
-    _addMinter(msg.sender);
-  }
+    Roles.Role private _minters;
 
-  modifier onlyMinter() {
-    require(isMinter(msg.sender));
-    _;
-  }
+    function initialize(address sender) public initializer {
+        if (!isMinter(sender)) {
+            _addMinter(sender);
+        }
+    }
 
-  function isMinter(address account) public view returns (bool) {
-    return minters.has(account);
-  }
+    modifier onlyMinter() {
+        require(isMinter(msg.sender));
+        _;
+    }
 
-  function addMinter(address account) public onlyMinter {
-    _addMinter(account);
-  }
+    function isMinter(address account) public view returns (bool) {
+        return _minters.has(account);
+    }
 
-  function renounceMinter() public {
-    _removeMinter(msg.sender);
-  }
+    function addMinter(address account) public onlyMinter {
+        _addMinter(account);
+    }
 
-  function _addMinter(address account) internal {
-    minters.add(account);
-    emit MinterAdded(account);
-  }
+    function renounceMinter() public {
+        _removeMinter(msg.sender);
+    }
 
-  function _removeMinter(address account) internal {
-    minters.remove(account);
-    emit MinterRemoved(account);
-  }
+    function _addMinter(address account) internal {
+        _minters.add(account);
+        emit MinterAdded(account);
+    }
+
+    function _removeMinter(address account) internal {
+        _minters.remove(account);
+        emit MinterRemoved(account);
+    }
+
+    uint256[50] private ______gap;
 }

contracts/access/roles/PauserRole.sol

@@ -1,43 +1,49 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
 import "../Roles.sol";
 
-contract PauserRole {
-  using Roles for Roles.Role;
 
-  event PauserAdded(address indexed account);
-  event PauserRemoved(address indexed account);
+contract PauserRole is Initializable {
+    using Roles for Roles.Role;
 
-  Roles.Role private pausers;
+    event PauserAdded(address indexed account);
+    event PauserRemoved(address indexed account);
 
-  constructor() internal {
-    _addPauser(msg.sender);
-  }
+    Roles.Role private _pausers;
 
-  modifier onlyPauser() {
-    require(isPauser(msg.sender));
-    _;
-  }
+    function initialize(address sender) public initializer {
+        if (!isPauser(sender)) {
+            _addPauser(sender);
+        }
+    }
 
-  function isPauser(address account) public view returns (bool) {
-    return pausers.has(account);
-  }
+    modifier onlyPauser() {
+        require(isPauser(msg.sender));
+        _;
+    }
 
-  function addPauser(address account) public onlyPauser {
-    _addPauser(account);
-  }
+    function isPauser(address account) public view returns (bool) {
+        return _pausers.has(account);
+    }
 
-  function renouncePauser() public {
-    _removePauser(msg.sender);
-  }
+    function addPauser(address account) public onlyPauser {
+        _addPauser(account);
+    }
 
-  function _addPauser(address account) internal {
-    pausers.add(account);
-    emit PauserAdded(account);
-  }
+    function renouncePauser() public {
+        _removePauser(msg.sender);
+    }
 
-  function _removePauser(address account) internal {
-    pausers.remove(account);
-    emit PauserRemoved(account);
-  }
+    function _addPauser(address account) internal {
+        _pausers.add(account);
+        emit PauserAdded(account);
+    }
+
+    function _removePauser(address account) internal {
+        _pausers.remove(account);
+        emit PauserRemoved(account);
+    }
+
+    uint256[50] private ______gap;
 }

contracts/access/roles/SignerRole.sol

@@ -1,43 +1,49 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
 import "../Roles.sol";
 
-contract SignerRole {
-  using Roles for Roles.Role;
 
-  event SignerAdded(address indexed account);
-  event SignerRemoved(address indexed account);
+contract SignerRole is Initializable {
+    using Roles for Roles.Role;
 
-  Roles.Role private signers;
+    event SignerAdded(address indexed account);
+    event SignerRemoved(address indexed account);
 
-  constructor() internal {
-    _addSigner(msg.sender);
-  }
+    Roles.Role private _signers;
 
-  modifier onlySigner() {
-    require(isSigner(msg.sender));
-    _;
-  }
+    function initialize(address sender) public initializer {
+        if (!isSigner(sender)) {
+            _addSigner(sender);
+        }
+    }
 
-  function isSigner(address account) public view returns (bool) {
-    return signers.has(account);
-  }
+    modifier onlySigner() {
+        require(isSigner(msg.sender));
+        _;
+    }
 
-  function addSigner(address account) public onlySigner {
-    _addSigner(account);
-  }
+    function isSigner(address account) public view returns (bool) {
+        return _signers.has(account);
+    }
 
-  function renounceSigner() public {
-    _removeSigner(msg.sender);
-  }
+    function addSigner(address account) public onlySigner {
+        _addSigner(account);
+    }
 
-  function _addSigner(address account) internal {
-    signers.add(account);
-    emit SignerAdded(account);
-  }
+    function renounceSigner() public {
+        _removeSigner(msg.sender);
+    }
 
-  function _removeSigner(address account) internal {
-    signers.remove(account);
-    emit SignerRemoved(account);
-  }
+    function _addSigner(address account) internal {
+        _signers.add(account);
+        emit SignerAdded(account);
+    }
+
+    function _removeSigner(address account) internal {
+        _signers.remove(account);
+        emit SignerRemoved(account);
+    }
+
+    uint256[50] private ______gap;
 }

contracts/access/roles/WhitelistAdminRole.sol

@@ -0,0 +1,53 @@
+pragma solidity ^0.5.2;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+
+import "../Roles.sol";
+
+/**
+ * @title WhitelistAdminRole
+ * @dev WhitelistAdmins are responsible for assigning and removing Whitelisted accounts.
+ */
+contract WhitelistAdminRole is Initializable {
+    using Roles for Roles.Role;
+
+    event WhitelistAdminAdded(address indexed account);
+    event WhitelistAdminRemoved(address indexed account);
+
+    Roles.Role private _whitelistAdmins;
+
+    function initialize(address sender) public initializer {
+        if (!isWhitelistAdmin(sender)) {
+            _addWhitelistAdmin(sender);
+        }
+    }
+
+    modifier onlyWhitelistAdmin() {
+        require(isWhitelistAdmin(msg.sender));
+        _;
+    }
+
+    function isWhitelistAdmin(address account) public view returns (bool) {
+        return _whitelistAdmins.has(account);
+    }
+
+    function addWhitelistAdmin(address account) public onlyWhitelistAdmin {
+        _addWhitelistAdmin(account);
+    }
+
+    function renounceWhitelistAdmin() public {
+        _removeWhitelistAdmin(msg.sender);
+    }
+
+    function _addWhitelistAdmin(address account) internal {
+        _whitelistAdmins.add(account);
+        emit WhitelistAdminAdded(account);
+    }
+
+    function _removeWhitelistAdmin(address account) internal {
+        _whitelistAdmins.remove(account);
+        emit WhitelistAdminRemoved(account);
+    }
+
+    uint256[50] private ______gap;
+}

contracts/access/roles/WhitelistedRole.sol

@@ -0,0 +1,58 @@
+pragma solidity ^0.5.2;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+
+import "../Roles.sol";
+import "./WhitelistAdminRole.sol";
+
+/**
+ * @title WhitelistedRole
+ * @dev Whitelisted accounts have been approved by a WhitelistAdmin to perform certain actions (e.g. participate in a
+ * crowdsale). This role is special in that the only accounts that can add it are WhitelistAdmins (who can also remove
+ * it), and not Whitelisteds themselves.
+ */
+contract WhitelistedRole is Initializable, WhitelistAdminRole {
+    using Roles for Roles.Role;
+
+    event WhitelistedAdded(address indexed account);
+    event WhitelistedRemoved(address indexed account);
+
+    Roles.Role private _whitelisteds;
+
+    modifier onlyWhitelisted() {
+        require(isWhitelisted(msg.sender));
+        _;
+    }
+
+    function initialize(address sender) public initializer {
+        WhitelistAdminRole.initialize(sender);
+    }
+
+    function isWhitelisted(address account) public view returns (bool) {
+        return _whitelisteds.has(account);
+    }
+
+    function addWhitelisted(address account) public onlyWhitelistAdmin {
+        _addWhitelisted(account);
+    }
+
+    function removeWhitelisted(address account) public onlyWhitelistAdmin {
+        _removeWhitelisted(account);
+    }
+
+    function renounceWhitelisted() public {
+        _removeWhitelisted(msg.sender);
+    }
+
+    function _addWhitelisted(address account) internal {
+        _whitelisteds.add(account);
+        emit WhitelistedAdded(account);
+    }
+
+    function _removeWhitelisted(address account) internal {
+        _whitelisteds.remove(account);
+        emit WhitelistedRemoved(account);
+    }
+
+    uint256[50] private ______gap;
+}

contracts/crowdsale/Crowdsale.sol

@@ -1,5 +1,6 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
 import "../token/ERC20/IERC20.sol";
 import "../math/SafeMath.sol";
 import "../token/ERC20/SafeERC20.sol";
@@ -11,231 +12,194 @@ import "../utils/ReentrancyGuard.sol";
  * allowing investors to purchase tokens with ether. This contract implements
  * such functionality in its most fundamental form and can be extended to provide additional
  * functionality and/or custom behavior.
- * The external interface represents the basic interface for purchasing tokens, and conform
- * the base architecture for crowdsales. They are *not* intended to be modified / overridden.
+ * The external interface represents the basic interface for purchasing tokens, and conforms
+ * the base architecture for crowdsales. It is *not* intended to be modified / overridden.
  * The internal interface conforms the extensible and modifiable surface of crowdsales. Override
  * the methods to add functionality. Consider using 'super' where appropriate to concatenate
  * behavior.
  */
-contract Crowdsale is ReentrancyGuard {
-  using SafeMath for uint256;
-  using SafeERC20 for IERC20;
+contract Crowdsale is Initializable, ReentrancyGuard {
+    using SafeMath for uint256;
+    using SafeERC20 for IERC20;
 
-  // The token being sold
-  IERC20 private _token;
+    // The token being sold
+    IERC20 private _token;
 
-  // Address where funds are collected
-  address private _wallet;
+    // Address where funds are collected
+    address payable private _wallet;
 
-  // How many token units a buyer gets per wei.
-  // The rate is the conversion between wei and the smallest and indivisible token unit.
-  // So, if you are using a rate of 1 with a ERC20Detailed token with 3 decimals called TOK
-  // 1 wei will give you 1 unit, or 0.001 TOK.
-  uint256 private _rate;
+    // How many token units a buyer gets per wei.
+    // The rate is the conversion between wei and the smallest and indivisible token unit.
+    // So, if you are using a rate of 1 with a ERC20Detailed token with 3 decimals called TOK
+    // 1 wei will give you 1 unit, or 0.001 TOK.
+    uint256 private _rate;
 
-  // Amount of wei raised
-  uint256 private _weiRaised;
+    // Amount of wei raised
+    uint256 private _weiRaised;
 
-  /**
-   * Event for token purchase logging
-   * @param purchaser who paid for the tokens
-   * @param beneficiary who got the tokens
-   * @param value weis paid for purchase
-   * @param amount amount of tokens purchased
-   */
-  event TokensPurchased(
-    address indexed purchaser,
-    address indexed beneficiary,
-    uint256 value,
-    uint256 amount
-  );
+    /**
+     * Event for token purchase logging
+     * @param purchaser who paid for the tokens
+     * @param beneficiary who got the tokens
+     * @param value weis paid for purchase
+     * @param amount amount of tokens purchased
+     */
+    event TokensPurchased(address indexed purchaser, address indexed beneficiary, uint256 value, uint256 amount);
 
-  /**
-   * @param rate Number of token units a buyer gets per wei
-   * @dev The rate is the conversion between wei and the smallest and indivisible
-   * token unit. So, if you are using a rate of 1 with a ERC20Detailed token
-   * with 3 decimals called TOK, 1 wei will give you 1 unit, or 0.001 TOK.
-   * @param wallet Address where collected funds will be forwarded to
-   * @param token Address of the token being sold
-   */
-  constructor(uint256 rate, address wallet, IERC20 token) internal {
-    require(rate > 0);
-    require(wallet != address(0));
-    require(token != address(0));
+    /**
+     * @param rate Number of token units a buyer gets per wei
+     * @dev The rate is the conversion between wei and the smallest and indivisible
+     * token unit. So, if you are using a rate of 1 with a ERC20Detailed token
+     * with 3 decimals called TOK, 1 wei will give you 1 unit, or 0.001 TOK.
+     * @param wallet Address where collected funds will be forwarded to
+     * @param token Address of the token being sold
+     */
+    function initialize(uint256 rate, address payable wallet, IERC20 token) public initializer {
+        require(rate > 0);
+        require(wallet != address(0));
+        require(address(token) != address(0));
 
-    _rate = rate;
-    _wallet = wallet;
-    _token = token;
-  }
+        _rate = rate;
+        _wallet = wallet;
+        _token = token;
+    }
 
-  // -----------------------------------------
-  // Crowdsale external interface
-  // -----------------------------------------
+    /**
+     * @dev fallback function ***DO NOT OVERRIDE***
+     * Note that other contracts will transfer funds with a base gas stipend
+     * of 2300, which is not enough to call buyTokens. Consider calling
+     * buyTokens directly when purchasing tokens from a contract.
+     */
+    function () external payable {
+        buyTokens(msg.sender);
+    }
 
-  /**
-   * @dev fallback function ***DO NOT OVERRIDE***
-   * Note that other contracts will transfer fund with a base gas stipend
-   * of 2300, which is not enough to call buyTokens. Consider calling
-   * buyTokens directly when purchasing tokens from a contract.
-   */
-  function () external payable {
-    buyTokens(msg.sender);
-  }
+    /**
+     * @return the token being sold.
+     */
+    function token() public view returns (IERC20) {
+        return _token;
+    }
 
-  /**
-   * @return the token being sold.
-   */
-  function token() public view returns(IERC20) {
-    return _token;
-  }
+    /**
+     * @return the address where funds are collected.
+     */
+    function wallet() public view returns (address payable) {
+        return _wallet;
+    }
 
-  /**
-   * @return the address where funds are collected.
-   */
-  function wallet() public view returns(address) {
-    return _wallet;
-  }
+    /**
+     * @return the number of token units a buyer gets per wei.
+     */
+    function rate() public view returns (uint256) {
+        return _rate;
+    }
 
-  /**
-   * @return the number of token units a buyer gets per wei.
-   */
-  function rate() public view returns(uint256) {
-    return _rate;
-  }
+    /**
+     * @return the amount of wei raised.
+     */
+    function weiRaised() public view returns (uint256) {
+        return _weiRaised;
+    }
 
-  /**
-   * @return the amount of wei raised.
-   */
-  function weiRaised() public view returns (uint256) {
-    return _weiRaised;
-  }
+    /**
+     * @dev low level token purchase ***DO NOT OVERRIDE***
+     * This function has a non-reentrancy guard, so it shouldn't be called by
+     * another `nonReentrant` function.
+     * @param beneficiary Recipient of the token purchase
+     */
+    function buyTokens(address beneficiary) public nonReentrant payable {
+        uint256 weiAmount = msg.value;
+        _preValidatePurchase(beneficiary, weiAmount);
 
-  /**
-   * @dev low level token purchase ***DO NOT OVERRIDE***
-   * This function has a non-reentrancy guard, so it shouldn't be called by
-   * another `nonReentrant` function.
-   * @param beneficiary Recipient of the token purchase
-   */
-  function buyTokens(address beneficiary) public nonReentrant payable {
+        // calculate token amount to be created
+        uint256 tokens = _getTokenAmount(weiAmount);
 
-    uint256 weiAmount = msg.value;
-    _preValidatePurchase(beneficiary, weiAmount);
+        // update state
+        _weiRaised = _weiRaised.add(weiAmount);
 
-    // calculate token amount to be created
-    uint256 tokens = _getTokenAmount(weiAmount);
+        _processPurchase(beneficiary, tokens);
+        emit TokensPurchased(msg.sender, beneficiary, weiAmount, tokens);
 
-    // update state
-    _weiRaised = _weiRaised.add(weiAmount);
+        _updatePurchasingState(beneficiary, weiAmount);
 
-    _processPurchase(beneficiary, tokens);
-    emit TokensPurchased(
-      msg.sender,
-      beneficiary,
-      weiAmount,
-      tokens
-    );
+        _forwardFunds();
+        _postValidatePurchase(beneficiary, weiAmount);
+    }
 
-    _updatePurchasingState(beneficiary, weiAmount);
+    function _hasBeenInitialized() internal view returns (bool) {
+        return ((_rate > 0) && (_wallet != address(0)) && (address(_token) != address(0)));
+    }
 
-    _forwardFunds();
-    _postValidatePurchase(beneficiary, weiAmount);
-  }
+    /**
+     * @dev Validation of an incoming purchase. Use require statements to revert state when conditions are not met.
+     * Use `super` in contracts that inherit from Crowdsale to extend their validations.
+     * Example from CappedCrowdsale.sol's _preValidatePurchase method:
+     *     super._preValidatePurchase(beneficiary, weiAmount);
+     *     require(weiRaised().add(weiAmount) <= cap);
+     * @param beneficiary Address performing the token purchase
+     * @param weiAmount Value in wei involved in the purchase
+     */
+    function _preValidatePurchase(address beneficiary, uint256 weiAmount) internal view {
+        require(beneficiary != address(0));
+        require(weiAmount != 0);
+    }
 
-  // -----------------------------------------
-  // Internal interface (extensible)
-  // -----------------------------------------
+    /**
+     * @dev Validation of an executed purchase. Observe state and use revert statements to undo rollback when valid
+     * conditions are not met.
+     * @param beneficiary Address performing the token purchase
+     * @param weiAmount Value in wei involved in the purchase
+     */
+    function _postValidatePurchase(address beneficiary, uint256 weiAmount) internal view {
+        // solhint-disable-previous-line no-empty-blocks
+    }
 
-  /**
-   * @dev Validation of an incoming purchase. Use require statements to revert state when conditions are not met. Use `super` in contracts that inherit from Crowdsale to extend their validations.
-   * Example from CappedCrowdsale.sol's _preValidatePurchase method:
-   *   super._preValidatePurchase(beneficiary, weiAmount);
-   *   require(weiRaised().add(weiAmount) <= cap);
-   * @param beneficiary Address performing the token purchase
-   * @param weiAmount Value in wei involved in the purchase
-   */
-  function _preValidatePurchase(
-    address beneficiary,
-    uint256 weiAmount
-  )
-    internal
-    view
-  {
-    require(beneficiary != address(0));
-    require(weiAmount != 0);
-  }
+    /**
+     * @dev Source of tokens. Override this method to modify the way in which the crowdsale ultimately gets and sends
+     * its tokens.
+     * @param beneficiary Address performing the token purchase
+     * @param tokenAmount Number of tokens to be emitted
+     */
+    function _deliverTokens(address beneficiary, uint256 tokenAmount) internal {
+        _token.safeTransfer(beneficiary, tokenAmount);
+    }
 
-  /**
-   * @dev Validation of an executed purchase. Observe state and use revert statements to undo rollback when valid conditions are not met.
-   * @param beneficiary Address performing the token purchase
-   * @param weiAmount Value in wei involved in the purchase
-   */
-  function _postValidatePurchase(
-    address beneficiary,
-    uint256 weiAmount
-  )
-    internal
-    view
-  {
-    // optional override
-  }
+    /**
+     * @dev Executed when a purchase has been validated and is ready to be executed. Doesn't necessarily emit/send
+     * tokens.
+     * @param beneficiary Address receiving the tokens
+     * @param tokenAmount Number of tokens to be purchased
+     */
+    function _processPurchase(address beneficiary, uint256 tokenAmount) internal {
+        _deliverTokens(beneficiary, tokenAmount);
+    }
 
-  /**
-   * @dev Source of tokens. Override this method to modify the way in which the crowdsale ultimately gets and sends its tokens.
-   * @param beneficiary Address performing the token purchase
-   * @param tokenAmount Number of tokens to be emitted
-   */
-  function _deliverTokens(
-    address beneficiary,
-    uint256 tokenAmount
-  )
-    internal
-  {
-    _token.safeTransfer(beneficiary, tokenAmount);
-  }
+    /**
+     * @dev Override for extensions that require an internal state to check for validity (current user contributions,
+     * etc.)
+     * @param beneficiary Address receiving the tokens
+     * @param weiAmount Value in wei involved in the purchase
+     */
+    function _updatePurchasingState(address beneficiary, uint256 weiAmount) internal {
+        // solhint-disable-previous-line no-empty-blocks
+    }
 
-  /**
-   * @dev Executed when a purchase has been validated and is ready to be executed. Doesn't necessarily emit/send tokens.
-   * @param beneficiary Address receiving the tokens
-   * @param tokenAmount Number of tokens to be purchased
-   */
-  function _processPurchase(
-    address beneficiary,
-    uint256 tokenAmount
-  )
-    internal
-  {
-    _deliverTokens(beneficiary, tokenAmount);
-  }
+    /**
+     * @dev Override to extend the way in which ether is converted to tokens.
+     * @param weiAmount Value in wei to be converted into tokens
+     * @return Number of tokens that can be purchased with the specified _weiAmount
+     */
+    function _getTokenAmount(uint256 weiAmount) internal view returns (uint256) {
+        return weiAmount.mul(_rate);
+    }
 
-  /**
-   * @dev Override for extensions that require an internal state to check for validity (current user contributions, etc.)
-   * @param beneficiary Address receiving the tokens
-   * @param weiAmount Value in wei involved in the purchase
-   */
-  function _updatePurchasingState(
-    address beneficiary,
-    uint256 weiAmount
-  )
-    internal
-  {
-    // optional override
-  }
+    /**
+     * @dev Determines how ETH is stored/forwarded on purchases.
+     */
+    function _forwardFunds() internal {
+        _wallet.transfer(msg.value);
+    }
 
-  /**
-   * @dev Override to extend the way in which ether is converted to tokens.
-   * @param weiAmount Value in wei to be converted into tokens
-   * @return Number of tokens that can be purchased with the specified _weiAmount
-   */
-  function _getTokenAmount(uint256 weiAmount)
-    internal view returns (uint256)
-  {
-    return weiAmount.mul(_rate);
-  }
-
-  /**
-   * @dev Determines how ETH is stored/forwarded on purchases.
-   */
-  function _forwardFunds() internal {
-    _wallet.transfer(msg.value);
-  }
+    uint256[50] private ______gap;
 }

contracts/crowdsale/distribution/FinalizableCrowdsale.sol

@@ -1,50 +1,50 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
 import "../../math/SafeMath.sol";
 import "../validation/TimedCrowdsale.sol";
 
 /**
  * @title FinalizableCrowdsale
- * @dev Extension of Crowdsale with a one-off finalization action, where one
+ * @dev Extension of TimedCrowdsale with a one-off finalization action, where one
  * can do extra work after finishing.
  */
-contract FinalizableCrowdsale is TimedCrowdsale {
-  using SafeMath for uint256;
+contract FinalizableCrowdsale is Initializable, TimedCrowdsale {
+    using SafeMath for uint256;
 
-  bool private _finalized;
+    bool private _finalized;
 
-  event CrowdsaleFinalized();
+    event CrowdsaleFinalized();
 
-  constructor() internal {
-    _finalized = false;
-  }
+    /**
+     * @return true if the crowdsale is finalized, false otherwise.
+     */
+    function finalized() public view returns (bool) {
+        return _finalized;
+    }
 
-  /**
-   * @return true if the crowdsale is finalized, false otherwise.
-   */
-  function finalized() public view returns (bool) {
-    return _finalized;
-  }
+    /**
+     * @dev Must be called after crowdsale ends, to do some extra finalization
+     * work. Calls the contract's finalization function.
+     */
+    function finalize() public {
+        require(!_finalized);
+        require(hasClosed());
 
-  /**
-   * @dev Must be called after crowdsale ends, to do some extra finalization
-   * work. Calls the contract's finalization function.
-   */
-  function finalize() public {
-    require(!_finalized);
-    require(hasClosed());
+        _finalized = true;
 
-    _finalized = true;
+        _finalization();
+        emit CrowdsaleFinalized();
+    }
 
-    _finalization();
-    emit CrowdsaleFinalized();
-  }
+    /**
+     * @dev Can be overridden to add finalization logic. The overriding function
+     * should call super._finalization() to ensure the chain of finalization is
+     * executed entirely.
+     */
+    function _finalization() internal {
+        // solhint-disable-previous-line no-empty-blocks
+    }
 
-  /**
-   * @dev Can be overridden to add finalization logic. The overriding function
-   * should call super._finalization() to ensure the chain of finalization is
-   * executed entirely.
-   */
-  function _finalization() internal {
-  }
+    uint256[50] private ______gap;
 }

contracts/crowdsale/distribution/PostDeliveryCrowdsale.sol

@@ -1,5 +1,6 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
 import "../validation/TimedCrowdsale.sol";
 import "../../math/SafeMath.sol";
 
@@ -7,44 +8,38 @@ import "../../math/SafeMath.sol";
  * @title PostDeliveryCrowdsale
  * @dev Crowdsale that locks tokens from withdrawal until it ends.
  */
-contract PostDeliveryCrowdsale is TimedCrowdsale {
-  using SafeMath for uint256;
+contract PostDeliveryCrowdsale is Initializable, TimedCrowdsale {
+    using SafeMath for uint256;
 
-  mapping(address => uint256) private _balances;
+    mapping(address => uint256) private _balances;
 
-  constructor() internal {}
+    /**
+     * @dev Withdraw tokens only after crowdsale ends.
+     * @param beneficiary Whose tokens will be withdrawn.
+     */
+    function withdrawTokens(address beneficiary) public {
+        require(hasClosed());
+        uint256 amount = _balances[beneficiary];
+        require(amount > 0);
+        _balances[beneficiary] = 0;
+        _deliverTokens(beneficiary, amount);
+    }
 
-  /**
-   * @dev Withdraw tokens only after crowdsale ends.
-   * @param beneficiary Whose tokens will be withdrawn.
-   */
-  function withdrawTokens(address beneficiary) public {
-    require(hasClosed());
-    uint256 amount = _balances[beneficiary];
-    require(amount > 0);
-    _balances[beneficiary] = 0;
-    _deliverTokens(beneficiary, amount);
-  }
+    /**
+     * @return the balance of an account.
+     */
+    function balanceOf(address account) public view returns (uint256) {
+        return _balances[account];
+    }
 
-  /**
-   * @return the balance of an account.
-   */
-  function balanceOf(address account) public view returns(uint256) {
-    return _balances[account];
-  }
-
-  /**
-   * @dev Overrides parent by storing balances instead of issuing tokens right away.
-   * @param beneficiary Token purchaser
-   * @param tokenAmount Amount of tokens purchased
-   */
-  function _processPurchase(
-    address beneficiary,
-    uint256 tokenAmount
-  )
-    internal
-  {
-    _balances[beneficiary] = _balances[beneficiary].add(tokenAmount);
-  }
+    /**
+     * @dev Overrides parent by storing balances instead of issuing tokens right away.
+     * @param beneficiary Token purchaser
+     * @param tokenAmount Amount of tokens purchased
+     */
+    function _processPurchase(address beneficiary, uint256 tokenAmount) internal {
+        _balances[beneficiary] = _balances[beneficiary].add(tokenAmount);
+    }
 
+    uint256[50] private ______gap;
 }

contracts/crowdsale/distribution/RefundableCrowdsale.sol

@@ -1,91 +1,92 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
 import "../../math/SafeMath.sol";
 import "./FinalizableCrowdsale.sol";
 import "../../payment/escrow/RefundEscrow.sol";
 
 /**
  * @title RefundableCrowdsale
- * @dev Extension of Crowdsale contract that adds a funding goal, and
- * the possibility of users getting a refund if goal is not met.
- * WARNING: note that if you allow tokens to be traded before the goal 
- * is met, then an attack is possible in which the attacker purchases 
- * tokens from the crowdsale and when they sees that the goal is 
- * unlikely to be met, they sell their tokens (possibly at a discount).
- * The attacker will be refunded when the crowdsale is finalized, and
- * the users that purchased from them will be left with worthless 
- * tokens. There are many possible ways to avoid this, like making the
- * the crowdsale inherit from PostDeliveryCrowdsale, or imposing 
- * restrictions on token trading until the crowdsale is finalized.
- * This is being discussed in 
- * https://github.com/OpenZeppelin/openzeppelin-solidity/issues/877
- * This contract will be updated when we agree on a general solution
- * for this problem.
+ * @dev Extension of FinalizableCrowdsale contract that adds a funding goal, and the possibility of users
+ * getting a refund if goal is not met.
+ *
+ * Deprecated, use RefundablePostDeliveryCrowdsale instead. Note that if you allow tokens to be traded before the goal
+ * is met, then an attack is possible in which the attacker purchases tokens from the crowdsale and when they sees that
+ * the goal is unlikely to be met, they sell their tokens (possibly at a discount). The attacker will be refunded when
+ * the crowdsale is finalized, and the users that purchased from them will be left with worthless tokens.
  */
-contract RefundableCrowdsale is FinalizableCrowdsale {
-  using SafeMath for uint256;
+contract RefundableCrowdsale is Initializable, FinalizableCrowdsale {
+    using SafeMath for uint256;
 
-  // minimum amount of funds to be raised in weis
-  uint256 private _goal;
+    // minimum amount of funds to be raised in weis
+    uint256 private _goal;
 
-  // refund escrow used to hold funds while crowdsale is running
-  RefundEscrow private _escrow;
+    // refund escrow used to hold funds while crowdsale is running
+    RefundEscrow private _escrow;
 
-  /**
-   * @dev Constructor, creates RefundEscrow.
-   * @param goal Funding goal
-   */
-  constructor(uint256 goal) internal {
-    require(goal > 0);
-    _escrow = new RefundEscrow(wallet());
-    _goal = goal;
-  }
+    /**
+     * @dev Constructor, creates RefundEscrow.
+     * @param goal Funding goal
+     */
+    function initialize(uint256 goal) public initializer {
+        // FinalizableCrowdsale depends on TimedCrowdsale
+        assert(TimedCrowdsale._hasBeenInitialized());
 
-  /**
-   * @return minimum amount of funds to be raised in wei.
-   */
-  function goal() public view returns(uint256) {
-    return _goal;
-  }
-
-  /**
-   * @dev Investors can claim refunds here if crowdsale is unsuccessful
-   * @param beneficiary Whose refund will be claimed.
-   */
-  function claimRefund(address beneficiary) public {
-    require(finalized());
-    require(!goalReached());
-
-    _escrow.withdraw(beneficiary);
-  }
-
-  /**
-   * @dev Checks whether funding goal was reached.
-   * @return Whether funding goal was reached
-   */
-  function goalReached() public view returns (bool) {
-    return weiRaised() >= _goal;
-  }
-
-  /**
-   * @dev escrow finalization task, called when finalize() is called
-   */
-  function _finalization() internal {
-    if (goalReached()) {
-      _escrow.close();
-      _escrow.beneficiaryWithdraw();
-    } else {
-      _escrow.enableRefunds();
+        require(goal > 0);
+        // conditional added to make initializer idempotent in case of diamond inheritance
+        if (address(_escrow) == address(0)) {
+            _escrow = new RefundEscrow();
+            _escrow.initialize(wallet(), address(this));
+        }
+        _goal = goal;
     }
 
-    super._finalization();
-  }
+    /**
+     * @return minimum amount of funds to be raised in wei.
+     */
+    function goal() public view returns (uint256) {
+        return _goal;
+    }
 
-  /**
-   * @dev Overrides Crowdsale fund forwarding, sending funds to escrow.
-   */
-  function _forwardFunds() internal {
-    _escrow.deposit.value(msg.value)(msg.sender);
-  }
+    /**
+     * @dev Investors can claim refunds here if crowdsale is unsuccessful
+     * @param refundee Whose refund will be claimed.
+     */
+    function claimRefund(address payable refundee) public {
+        require(finalized());
+        require(!goalReached());
 
+        _escrow.withdraw(refundee);
+    }
+
+    /**
+     * @dev Checks whether funding goal was reached.
+     * @return Whether funding goal was reached
+     */
+    function goalReached() public view returns (bool) {
+        return weiRaised() >= _goal;
+    }
+
+    /**
+     * @dev escrow finalization task, called when finalize() is called
+     */
+    function _finalization() internal {
+        if (goalReached()) {
+            _escrow.close();
+            _escrow.beneficiaryWithdraw();
+        } else {
+            _escrow.enableRefunds();
+        }
+
+        super._finalization();
+    }
+
+    /**
+     * @dev Overrides Crowdsale fund forwarding, sending funds to escrow.
+     */
+    function _forwardFunds() internal {
+        _escrow.deposit.value(msg.value)(msg.sender);
+    }
+
+    uint256[50] private ______gap;
 }

contracts/crowdsale/distribution/RefundablePostDeliveryCrowdsale.sol

@@ -0,0 +1,23 @@
+pragma solidity ^0.5.2;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+
+import "./RefundableCrowdsale.sol";
+import "./PostDeliveryCrowdsale.sol";
+
+/**
+ * @title RefundablePostDeliveryCrowdsale
+ * @dev Extension of RefundableCrowdsale contract that only delivers the tokens
+ * once the crowdsale has closed and the goal met, preventing refunds to be issued
+ * to token holders.
+ */
+contract RefundablePostDeliveryCrowdsale is Initializable, RefundableCrowdsale, PostDeliveryCrowdsale {
+    function withdrawTokens(address beneficiary) public {
+        require(finalized());
+        require(goalReached());
+
+        super.withdrawTokens(beneficiary);
+    }
+
+    uint256[50] private ______gap;
+}

contracts/crowdsale/emission/AllowanceCrowdsale.sol

@@ -1,5 +1,6 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
 import "../Crowdsale.sol";
 import "../../token/ERC20/IERC20.sol";
 import "../../token/ERC20/SafeERC20.sol";
@@ -10,50 +11,46 @@ import "../../math/Math.sol";
  * @title AllowanceCrowdsale
  * @dev Extension of Crowdsale where tokens are held by a wallet, which approves an allowance to the crowdsale.
  */
-contract AllowanceCrowdsale is Crowdsale {
-  using SafeMath for uint256;
-  using SafeERC20 for IERC20;
+contract AllowanceCrowdsale is Initializable, Crowdsale {
+    using SafeMath for uint256;
+    using SafeERC20 for IERC20;
 
-  address private _tokenWallet;
+    address private _tokenWallet;
 
-  /**
-   * @dev Constructor, takes token wallet address.
-   * @param tokenWallet Address holding the tokens, which has approved allowance to the crowdsale
-   */
-  constructor(address tokenWallet) internal {
-    require(tokenWallet != address(0));
-    _tokenWallet = tokenWallet;
-  }
+    /**
+     * @dev Constructor, takes token wallet address.
+     * @param tokenWallet Address holding the tokens, which has approved allowance to the crowdsale
+     */
+    function initialize(address tokenWallet) public initializer {
+        assert(Crowdsale._hasBeenInitialized());
 
-  /**
-   * @return the address of the wallet that will hold the tokens.
-   */
-  function tokenWallet() public view returns(address) {
-    return _tokenWallet;
-  }
+        require(tokenWallet != address(0));
+        _tokenWallet = tokenWallet;
+    }
 
-  /**
-   * @dev Checks the amount of tokens left in the allowance.
-   * @return Amount of tokens left in the allowance
-   */
-  function remainingTokens() public view returns (uint256) {
-    return Math.min(
-      token().balanceOf(_tokenWallet),
-      token().allowance(_tokenWallet, this)
-    );
-  }
+    /**
+     * @return the address of the wallet that will hold the tokens.
+     */
+    function tokenWallet() public view returns (address) {
+        return _tokenWallet;
+    }
 
-  /**
-   * @dev Overrides parent behavior by transferring tokens from wallet.
-   * @param beneficiary Token purchaser
-   * @param tokenAmount Amount of tokens purchased
-   */
-  function _deliverTokens(
-    address beneficiary,
-    uint256 tokenAmount
-  )
-    internal
-  {
-    token().safeTransferFrom(_tokenWallet, beneficiary, tokenAmount);
-  }
+    /**
+     * @dev Checks the amount of tokens left in the allowance.
+     * @return Amount of tokens left in the allowance
+     */
+    function remainingTokens() public view returns (uint256) {
+        return Math.min(token().balanceOf(_tokenWallet), token().allowance(_tokenWallet, address(this)));
+    }
+
+    /**
+     * @dev Overrides parent behavior by transferring tokens from wallet.
+     * @param beneficiary Token purchaser
+     * @param tokenAmount Amount of tokens purchased
+     */
+    function _deliverTokens(address beneficiary, uint256 tokenAmount) internal {
+        token().safeTransferFrom(_tokenWallet, beneficiary, tokenAmount);
+    }
+
+    uint256[50] private ______gap;
 }

contracts/crowdsale/emission/MintedCrowdsale.sol

@@ -1,5 +1,6 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
 import "../Crowdsale.sol";
 import "../../token/ERC20/ERC20Mintable.sol";
 
@@ -8,22 +9,16 @@ import "../../token/ERC20/ERC20Mintable.sol";
  * @dev Extension of Crowdsale contract whose tokens are minted in each purchase.
  * Token ownership should be transferred to MintedCrowdsale for minting.
  */
-contract MintedCrowdsale is Crowdsale {
-  constructor() internal {}
+contract MintedCrowdsale is Initializable, Crowdsale {
+    /**
+     * @dev Overrides delivery by minting tokens upon purchase.
+     * @param beneficiary Token purchaser
+     * @param tokenAmount Number of tokens to be minted
+     */
+    function _deliverTokens(address beneficiary, uint256 tokenAmount) internal {
+        // Potentially dangerous assumption about the type of the token.
+        require(ERC20Mintable(address(token())).mint(beneficiary, tokenAmount));
+    }
 
-  /**
-   * @dev Overrides delivery by minting tokens upon purchase.
-   * @param beneficiary Token purchaser
-   * @param tokenAmount Number of tokens to be minted
-   */
-  function _deliverTokens(
-    address beneficiary,
-    uint256 tokenAmount
-  )
-    internal
-  {
-    // Potentially dangerous assumption about the type of the token.
-    require(
-      ERC20Mintable(address(token())).mint(beneficiary, tokenAmount));
-  }
+    uint256[50] private ______gap;
 }

contracts/crowdsale/price/IncreasingPriceCrowdsale.sol

@@ -1,5 +1,6 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
 import "../validation/TimedCrowdsale.sol";
 import "../../math/SafeMath.sol";
 
@@ -9,73 +10,74 @@ import "../../math/SafeMath.sol";
  * Note that what should be provided to the constructor is the initial and final _rates_, that is,
  * the amount of tokens per wei contributed. Thus, the initial rate must be greater than the final rate.
  */
-contract IncreasingPriceCrowdsale is TimedCrowdsale {
-  using SafeMath for uint256;
+contract IncreasingPriceCrowdsale is Initializable, TimedCrowdsale {
+    using SafeMath for uint256;
 
-  uint256 private _initialRate;
-  uint256 private _finalRate;
+    uint256 private _initialRate;
+    uint256 private _finalRate;
 
-  /**
-   * @dev Constructor, takes initial and final rates of tokens received per wei contributed.
-   * @param initialRate Number of tokens a buyer gets per wei at the start of the crowdsale
-   * @param finalRate Number of tokens a buyer gets per wei at the end of the crowdsale
-   */
-  constructor(uint256 initialRate, uint256 finalRate) internal {
-    require(finalRate > 0);
-    require(initialRate > finalRate);
-    _initialRate = initialRate;
-    _finalRate = finalRate;
-  }
+    /**
+     * @dev Constructor, takes initial and final rates of tokens received per wei contributed.
+     * @param initialRate Number of tokens a buyer gets per wei at the start of the crowdsale
+     * @param finalRate Number of tokens a buyer gets per wei at the end of the crowdsale
+     */
+    function initialize(uint256 initialRate, uint256 finalRate) public initializer {
+        assert(TimedCrowdsale._hasBeenInitialized());
 
-  /**
-   * The base rate function is overridden to revert, since this crowdsale doens't use it, and
-   * all calls to it are a mistake.
-   */
-  function rate() public view returns(uint256) {
-    revert();
-  }
-
-  /**
-   * @return the initial rate of the crowdsale.
-   */
-  function initialRate() public view returns(uint256) {
-    return _initialRate;
-  }
-
-  /**
-   * @return the final rate of the crowdsale.
-   */
-  function finalRate() public view returns (uint256) {
-    return _finalRate;
-  }
-
-  /**
-   * @dev Returns the rate of tokens per wei at the present time.
-   * Note that, as price _increases_ with time, the rate _decreases_.
-   * @return The number of tokens a buyer gets per wei at a given time
-   */
-  function getCurrentRate() public view returns (uint256) {
-    if (!isOpen()) {
-      return 0;
+        require(finalRate > 0);
+        require(initialRate > finalRate);
+        _initialRate = initialRate;
+        _finalRate = finalRate;
     }
 
-    // solium-disable-next-line security/no-block-members
-    uint256 elapsedTime = block.timestamp.sub(openingTime());
-    uint256 timeRange = closingTime().sub(openingTime());
-    uint256 rateRange = _initialRate.sub(_finalRate);
-    return _initialRate.sub(elapsedTime.mul(rateRange).div(timeRange));
-  }
+    /**
+     * The base rate function is overridden to revert, since this crowdsale doesn't use it, and
+     * all calls to it are a mistake.
+     */
+    function rate() public view returns (uint256) {
+        revert();
+    }
 
-  /**
-   * @dev Overrides parent method taking into account variable rate.
-   * @param weiAmount The value in wei to be converted into tokens
-   * @return The number of tokens _weiAmount wei will buy at present time
-   */
-  function _getTokenAmount(uint256 weiAmount)
-    internal view returns (uint256)
-  {
-    uint256 currentRate = getCurrentRate();
-    return currentRate.mul(weiAmount);
-  }
+    /**
+     * @return the initial rate of the crowdsale.
+     */
+    function initialRate() public view returns (uint256) {
+        return _initialRate;
+    }
 
+    /**
+     * @return the final rate of the crowdsale.
+     */
+    function finalRate() public view returns (uint256) {
+        return _finalRate;
+    }
+
+    /**
+     * @dev Returns the rate of tokens per wei at the present time.
+     * Note that, as price _increases_ with time, the rate _decreases_.
+     * @return The number of tokens a buyer gets per wei at a given time
+     */
+    function getCurrentRate() public view returns (uint256) {
+        if (!isOpen()) {
+            return 0;
+        }
+
+        // solhint-disable-next-line not-rely-on-time
+        uint256 elapsedTime = block.timestamp.sub(openingTime());
+        uint256 timeRange = closingTime().sub(openingTime());
+        uint256 rateRange = _initialRate.sub(_finalRate);
+        return _initialRate.sub(elapsedTime.mul(rateRange).div(timeRange));
+    }
+
+    /**
+     * @dev Overrides parent method taking into account variable rate.
+     * @param weiAmount The value in wei to be converted into tokens
+     * @return The number of tokens _weiAmount wei will buy at present time
+     */
+    function _getTokenAmount(uint256 weiAmount) internal view returns (uint256) {
+        uint256 currentRate = getCurrentRate();
+        return currentRate.mul(weiAmount);
+    }
+
+    uint256[50] private ______gap;
 }

contracts/crowdsale/validation/CappedCrowdsale.sol

@@ -1,5 +1,6 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
 import "../../math/SafeMath.sol";
 import "../Crowdsale.sol";
 
@@ -7,49 +8,46 @@ import "../Crowdsale.sol";
  * @title CappedCrowdsale
  * @dev Crowdsale with a limit for total contributions.
  */
-contract CappedCrowdsale is Crowdsale {
-  using SafeMath for uint256;
+contract CappedCrowdsale is Initializable, Crowdsale {
+    using SafeMath for uint256;
 
-  uint256 private _cap;
+    uint256 private _cap;
 
-  /**
-   * @dev Constructor, takes maximum amount of wei accepted in the crowdsale.
-   * @param cap Max amount of wei to be contributed
-   */
-  constructor(uint256 cap) internal {
-    require(cap > 0);
-    _cap = cap;
-  }
+    /**
+     * @dev Constructor, takes maximum amount of wei accepted in the crowdsale.
+     * @param cap Max amount of wei to be contributed
+     */
+    function initialize(uint256 cap) public initializer {
+        assert(Crowdsale._hasBeenInitialized());
 
-  /**
-   * @return the cap of the crowdsale.
-   */
-  function cap() public view returns(uint256) {
-    return _cap;
-  }
+        require(cap > 0);
+        _cap = cap;
+    }
 
-  /**
-   * @dev Checks whether the cap has been reached.
-   * @return Whether the cap was reached
-   */
-  function capReached() public view returns (bool) {
-    return weiRaised() >= _cap;
-  }
+    /**
+     * @return the cap of the crowdsale.
+     */
+    function cap() public view returns (uint256) {
+        return _cap;
+    }
 
-  /**
-   * @dev Extend parent behavior requiring purchase to respect the funding cap.
-   * @param beneficiary Token purchaser
-   * @param weiAmount Amount of wei contributed
-   */
-  function _preValidatePurchase(
-    address beneficiary,
-    uint256 weiAmount
-  )
-    internal
-    view
-  {
-    super._preValidatePurchase(beneficiary, weiAmount);
-    require(weiRaised().add(weiAmount) <= _cap);
-  }
+    /**
+     * @dev Checks whether the cap has been reached.
+     * @return Whether the cap was reached
+     */
+    function capReached() public view returns (bool) {
+        return weiRaised() >= _cap;
+    }
 
+    /**
+     * @dev Extend parent behavior requiring purchase to respect the funding cap.
+     * @param beneficiary Token purchaser
+     * @param weiAmount Amount of wei contributed
+     */
+    function _preValidatePurchase(address beneficiary, uint256 weiAmount) internal view {
+        super._preValidatePurchase(beneficiary, weiAmount);
+        require(weiRaised().add(weiAmount) <= _cap);
+    }
+
+    uint256[50] private ______gap;
 }

contracts/crowdsale/validation/IndividuallyCappedCrowdsale.sol

@@ -1,5 +1,6 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
 import "../../math/SafeMath.sol";
 import "../Crowdsale.sol";
 import "../../access/roles/CapperRole.sol";
@@ -8,74 +9,64 @@ import "../../access/roles/CapperRole.sol";
  * @title IndividuallyCappedCrowdsale
  * @dev Crowdsale with per-beneficiary caps.
  */
-contract IndividuallyCappedCrowdsale is Crowdsale, CapperRole {
-  using SafeMath for uint256;
+contract IndividuallyCappedCrowdsale is Initializable, Crowdsale, CapperRole {
+    using SafeMath for uint256;
 
-  mapping(address => uint256) private _contributions;
-  mapping(address => uint256) private _caps;
+    mapping(address => uint256) private _contributions;
+    mapping(address => uint256) private _caps;
 
-  constructor() internal {}
+    function initialize(address sender) public initializer {
+        assert(Crowdsale._hasBeenInitialized());
 
-  /**
-   * @dev Sets a specific beneficiary's maximum contribution.
-   * @param beneficiary Address to be capped
-   * @param cap Wei limit for individual contribution
-   */
-  function setCap(address beneficiary, uint256 cap) external onlyCapper {
-    _caps[beneficiary] = cap;
-  }
+        CapperRole.initialize(sender);
+    }
 
-  /**
-   * @dev Returns the cap of a specific beneficiary.
-   * @param beneficiary Address whose cap is to be checked
-   * @return Current cap for individual beneficiary
-   */
-  function getCap(address beneficiary) public view returns (uint256) {
-    return _caps[beneficiary];
-  }
+    /**
+     * @dev Sets a specific beneficiary's maximum contribution.
+     * @param beneficiary Address to be capped
+     * @param cap Wei limit for individual contribution
+     */
+    function setCap(address beneficiary, uint256 cap) external onlyCapper {
+        _caps[beneficiary] = cap;
+    }
 
-  /**
-   * @dev Returns the amount contributed so far by a specific beneficiary.
-   * @param beneficiary Address of contributor
-   * @return Beneficiary contribution so far
-   */
-  function getContribution(address beneficiary)
-    public view returns (uint256)
-  {
-    return _contributions[beneficiary];
-  }
+    /**
+     * @dev Returns the cap of a specific beneficiary.
+     * @param beneficiary Address whose cap is to be checked
+     * @return Current cap for individual beneficiary
+     */
+    function getCap(address beneficiary) public view returns (uint256) {
+        return _caps[beneficiary];
+    }
 
-  /**
-   * @dev Extend parent behavior requiring purchase to respect the beneficiary's funding cap.
-   * @param beneficiary Token purchaser
-   * @param weiAmount Amount of wei contributed
-   */
-  function _preValidatePurchase(
-    address beneficiary,
-    uint256 weiAmount
-  )
-    internal
-    view
-  {
-    super._preValidatePurchase(beneficiary, weiAmount);
-    require(
-      _contributions[beneficiary].add(weiAmount) <= _caps[beneficiary]);
-  }
+    /**
+     * @dev Returns the amount contributed so far by a specific beneficiary.
+     * @param beneficiary Address of contributor
+     * @return Beneficiary contribution so far
+     */
+    function getContribution(address beneficiary) public view returns (uint256) {
+        return _contributions[beneficiary];
+    }
 
-  /**
-   * @dev Extend parent behavior to update beneficiary contributions
-   * @param beneficiary Token purchaser
-   * @param weiAmount Amount of wei contributed
-   */
-  function _updatePurchasingState(
-    address beneficiary,
-    uint256 weiAmount
-  )
-    internal
-  {
-    super._updatePurchasingState(beneficiary, weiAmount);
-    _contributions[beneficiary] = _contributions[beneficiary].add(
-      weiAmount);
-  }
+    /**
+     * @dev Extend parent behavior requiring purchase to respect the beneficiary's funding cap.
+     * @param beneficiary Token purchaser
+     * @param weiAmount Amount of wei contributed
+     */
+    function _preValidatePurchase(address beneficiary, uint256 weiAmount) internal view {
+        super._preValidatePurchase(beneficiary, weiAmount);
+        require(_contributions[beneficiary].add(weiAmount) <= _caps[beneficiary]);
+    }
 
+    /**
+     * @dev Extend parent behavior to update beneficiary contributions
+     * @param beneficiary Token purchaser
+     * @param weiAmount Amount of wei contributed
+     */
+    function _updatePurchasingState(address beneficiary, uint256 weiAmount) internal {
+        super._updatePurchasingState(beneficiary, weiAmount);
+        _contributions[beneficiary] = _contributions[beneficiary].add(weiAmount);
+    }
+
+    uint256[50] private ______gap;
 }

contracts/crowdsale/validation/PausableCrowdsale.sol

@@ -0,0 +1,31 @@
+pragma solidity ^0.5.2;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+
+import "../Crowdsale.sol";
+import "../../lifecycle/Pausable.sol";
+
+/**
+ * @title PausableCrowdsale
+ * @dev Extension of Crowdsale contract where purchases can be paused and unpaused by the pauser role.
+ */
+contract PausableCrowdsale is Initializable, Crowdsale, Pausable {
+    function initialize(address sender) public initializer {
+        assert(Crowdsale._hasBeenInitialized());
+
+        Pausable.initialize(sender);
+    }
+
+    /**
+     * @dev Validation of an incoming purchase. Use require statements to revert state when conditions are not met.
+     * Use super to concatenate validations.
+     * Adds the validation that the crowdsale must not be paused.
+     * @param _beneficiary Address performing the token purchase
+     * @param _weiAmount Value in wei involved in the purchase
+     */
+    function _preValidatePurchase(address _beneficiary, uint256 _weiAmount) internal view whenNotPaused {
+        return super._preValidatePurchase(_beneficiary, _weiAmount);
+    }
+
+    uint256[50] private ______gap;
+}

contracts/crowdsale/validation/TimedCrowdsale.sol

@@ -1,5 +1,6 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
 import "../../math/SafeMath.sol";
 import "../Crowdsale.sol";
 
@@ -7,79 +8,98 @@ import "../Crowdsale.sol";
  * @title TimedCrowdsale
  * @dev Crowdsale accepting contributions only within a time frame.
  */
-contract TimedCrowdsale is Crowdsale {
-  using SafeMath for uint256;
+contract TimedCrowdsale is Initializable, Crowdsale {
+    using SafeMath for uint256;
 
-  uint256 private _openingTime;
-  uint256 private _closingTime;
+    uint256 private _openingTime;
+    uint256 private _closingTime;
 
-  /**
-   * @dev Reverts if not in crowdsale time range.
-   */
-  modifier onlyWhileOpen {
-    require(isOpen());
-    _;
-  }
+    /**
+     * Event for crowdsale extending
+     * @param newClosingTime new closing time
+     * @param prevClosingTime old closing time
+     */
+    event TimedCrowdsaleExtended(uint256 prevClosingTime, uint256 newClosingTime);
 
-  /**
-   * @dev Constructor, takes crowdsale opening and closing times.
-   * @param openingTime Crowdsale opening time
-   * @param closingTime Crowdsale closing time
-   */
-  constructor(uint256 openingTime, uint256 closingTime) internal {
-    // solium-disable-next-line security/no-block-members
-    require(openingTime >= block.timestamp);
-    require(closingTime > openingTime);
+    /**
+     * @dev Reverts if not in crowdsale time range.
+     */
+    modifier onlyWhileOpen {
+        require(isOpen());
+        _;
+    }
 
-    _openingTime = openingTime;
-    _closingTime = closingTime;
-  }
+    /**
+     * @dev Constructor, takes crowdsale opening and closing times.
+     * @param openingTime Crowdsale opening time
+     * @param closingTime Crowdsale closing time
+     */
+    function initialize(uint256 openingTime, uint256 closingTime) public initializer {
+        assert(Crowdsale._hasBeenInitialized());
 
-  /**
-   * @return the crowdsale opening time.
-   */
-  function openingTime() public view returns(uint256) {
-    return _openingTime;
-  }
+        // solhint-disable-next-line not-rely-on-time
+        require(openingTime >= block.timestamp);
+        require(closingTime > openingTime);
 
-  /**
-   * @return the crowdsale closing time.
-   */
-  function closingTime() public view returns(uint256) {
-    return _closingTime;
-  }
+        _openingTime = openingTime;
+        _closingTime = closingTime;
+    }
 
-  /**
-   * @return true if the crowdsale is open, false otherwise.
-   */
-  function isOpen() public view returns (bool) {
-    // solium-disable-next-line security/no-block-members
-    return block.timestamp >= _openingTime && block.timestamp <= _closingTime;
-  }
+    /**
+     * @return the crowdsale opening time.
+     */
+    function openingTime() public view returns (uint256) {
+        return _openingTime;
+    }
 
-  /**
-   * @dev Checks whether the period in which the crowdsale is open has already elapsed.
-   * @return Whether crowdsale period has elapsed
-   */
-  function hasClosed() public view returns (bool) {
-    // solium-disable-next-line security/no-block-members
-    return block.timestamp > _closingTime;
-  }
+    /**
+     * @return the crowdsale closing time.
+     */
+    function closingTime() public view returns (uint256) {
+        return _closingTime;
+    }
 
-  /**
-   * @dev Extend parent behavior requiring to be within contributing period
-   * @param beneficiary Token purchaser
-   * @param weiAmount Amount of wei contributed
-   */
-  function _preValidatePurchase(
-    address beneficiary,
-    uint256 weiAmount
-  )
-    internal
-    onlyWhileOpen
-    view
-  {
-    super._preValidatePurchase(beneficiary, weiAmount);
-  }
+    /**
+     * @return true if the crowdsale is open, false otherwise.
+     */
+    function isOpen() public view returns (bool) {
+        // solhint-disable-next-line not-rely-on-time
+        return block.timestamp >= _openingTime && block.timestamp <= _closingTime;
+    }
 
+    /**
+     * @dev Checks whether the period in which the crowdsale is open has already elapsed.
+     * @return Whether crowdsale period has elapsed
+     */
+    function hasClosed() public view returns (bool) {
+        // solhint-disable-next-line not-rely-on-time
+        return block.timestamp > _closingTime;
+    }
+
+    function _hasBeenInitialized() internal view returns (bool) {
+        return ((_openingTime > 0) && (_closingTime > 0));
+    }
+
+    /**
+     * @dev Extend parent behavior requiring to be within contributing period
+     * @param beneficiary Token purchaser
+     * @param weiAmount Amount of wei contributed
+     */
+    function _preValidatePurchase(address beneficiary, uint256 weiAmount) internal onlyWhileOpen view {
+        super._preValidatePurchase(beneficiary, weiAmount);
+    }
+
+    /**
+     * @dev Extend crowdsale
+     * @param newClosingTime Crowdsale closing time
+     */
+    function _extendTime(uint256 newClosingTime) internal {
+        require(!hasClosed());
+        require(newClosingTime > _closingTime);
+
+        emit TimedCrowdsaleExtended(_closingTime, newClosingTime);
+        _closingTime = newClosingTime;
+    }
+
+    uint256[50] private ______gap;
 }

contracts/crowdsale/validation/WhitelistCrowdsale.sol

@@ -0,0 +1,29 @@
+pragma solidity ^0.5.2;
+import "../Crowdsale.sol";
+import "../../access/roles/WhitelistedRole.sol";
+
+
+/**
+ * @title WhitelistCrowdsale
+ * @dev Crowdsale in which only whitelisted users can contribute.
+ */
+contract WhitelistCrowdsale is Initializable, WhitelistedRole, Crowdsale {
+    function initialize(address sender) public initializer {
+        WhitelistedRole.initialize(sender);
+
+        assert(Crowdsale._hasBeenInitialized());
+    }
+
+    /**
+     * @dev Extend parent behavior requiring beneficiary to be whitelisted. Note that no
+     * restriction is imposed on the account sending the transaction.
+     * @param _beneficiary Token beneficiary
+     * @param _weiAmount Amount of wei contributed
+     */
+    function _preValidatePurchase(address _beneficiary, uint256 _weiAmount) internal view {
+        require(isWhitelisted(_beneficiary));
+        super._preValidatePurchase(_beneficiary, _weiAmount);
+    }
+
+    uint256[50] private ______gap;
+}

contracts/cryptography/ECDSA.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
 /**
  * @title Elliptic curve signature operations
@@ -8,64 +8,60 @@ pragma solidity ^0.4.24;
  */
 
 library ECDSA {
+    /**
+     * @dev Recover signer address from a message by using their signature
+     * @param hash bytes32 message, the hash is the signed message. What is recovered is the signer address.
+     * @param signature bytes signature, the signature is generated using web3.eth.sign()
+     */
+    function recover(bytes32 hash, bytes memory signature) internal pure returns (address) {
+        // Check the signature length
+        if (signature.length != 65) {
+            return (address(0));
+        }
 
-  /**
-   * @dev Recover signer address from a message by using their signature
-   * @param hash bytes32 message, the hash is the signed message. What is recovered is the signer address.
-   * @param signature bytes signature, the signature is generated using web3.eth.sign()
-   */
-  function recover(bytes32 hash, bytes signature)
-    internal
-    pure
-    returns (address)
-  {
-    bytes32 r;
-    bytes32 s;
-    uint8 v;
+        // Divide the signature in r, s and v variables
+        bytes32 r;
+        bytes32 s;
+        uint8 v;
 
-    // Check the signature length
-    if (signature.length != 65) {
-      return (address(0));
+        // ecrecover takes the signature parameters, and the only way to get them
+        // currently is to use assembly.
+        // solhint-disable-next-line no-inline-assembly
+        assembly {
+            r := mload(add(signature, 0x20))
+            s := mload(add(signature, 0x40))
+            v := byte(0, mload(add(signature, 0x60)))
+        }
+
+        // EIP-2 still allows signature malleability for ecrecover(). Remove this possibility and make the signature
+        // unique. Appendix F in the Ethereum Yellow paper (https://ethereum.github.io/yellowpaper/paper.pdf), defines
+        // the valid range for s in (281): 0 < s < secp256k1n ÷ 2 + 1, and for v in (282): v ∈ {27, 28}. Most
+        // signatures from current libraries generate a unique signature with an s-value in the lower half order.
+        //
+        // If your library generates malleable signatures, such as s-values in the upper range, calculate a new s-value
+        // with 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141 - s1 and flip v from 27 to 28 or
+        // vice versa. If your library also generates signatures with 0/1 for v instead 27/28, add 27 to v to accept
+        // these malleable signatures as well.
+        if (uint256(s) > 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0) {
+            return address(0);
+        }
+
+        if (v != 27 && v != 28) {
+            return address(0);
+        }
+
+        // If the signature is valid (and not malleable), return the signer address
+        return ecrecover(hash, v, r, s);
     }
 
-    // Divide the signature in r, s and v variables
-    // ecrecover takes the signature parameters, and the only way to get them
-    // currently is to use assembly.
-    // solium-disable-next-line security/no-inline-assembly
-    assembly {
-      r := mload(add(signature, 0x20))
-      s := mload(add(signature, 0x40))
-      v := byte(0, mload(add(signature, 0x60)))
+    /**
+     * toEthSignedMessageHash
+     * @dev prefix a bytes32 value with "\x19Ethereum Signed Message:"
+     * and hash the result
+     */
+    function toEthSignedMessageHash(bytes32 hash) internal pure returns (bytes32) {
+        // 32 is the length in bytes of hash,
+        // enforced by the type signature above
+        return keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n32", hash));
     }
-
-    // Version of signature should be 27 or 28, but 0 and 1 are also possible versions
-    if (v < 27) {
-      v += 27;
-    }
-
-    // If the version is correct return the signer address
-    if (v != 27 && v != 28) {
-      return (address(0));
-    } else {
-      // solium-disable-next-line arg-overflow
-      return ecrecover(hash, v, r, s);
-    }
-  }
-
-  /**
-   * toEthSignedMessageHash
-   * @dev prefix a bytes32 value with "\x19Ethereum Signed Message:"
-   * and hash the result
-   */
-  function toEthSignedMessageHash(bytes32 hash)
-    internal
-    pure
-    returns (bytes32)
-  {
-    // 32 is the length in bytes of hash,
-    // enforced by the type signature above
-    return keccak256(
-      abi.encodePacked("\x19Ethereum Signed Message:\n32", hash)
-    );
-  }
 }

contracts/cryptography/MerkleProof.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
 /**
  * @title MerkleProof
@@ -6,37 +6,29 @@ pragma solidity ^0.4.24;
  * https://github.com/ameensol/merkle-tree-solidity/blob/master/src/MerkleProof.sol
  */
 library MerkleProof {
-  /**
-   * @dev Verifies a Merkle proof proving the existence of a leaf in a Merkle tree. Assumes that each pair of leaves
-   * and each pair of pre-images are sorted.
-   * @param proof Merkle proof containing sibling hashes on the branch from the leaf to the root of the Merkle tree
-   * @param root Merkle root
-   * @param leaf Leaf of Merkle tree
-   */
-  function verify(
-    bytes32[] proof,
-    bytes32 root,
-    bytes32 leaf
-  )
-    internal
-    pure
-    returns (bool)
-  {
-    bytes32 computedHash = leaf;
+    /**
+     * @dev Verifies a Merkle proof proving the existence of a leaf in a Merkle tree. Assumes that each pair of leaves
+     * and each pair of pre-images are sorted.
+     * @param proof Merkle proof containing sibling hashes on the branch from the leaf to the root of the Merkle tree
+     * @param root Merkle root
+     * @param leaf Leaf of Merkle tree
+     */
+    function verify(bytes32[] memory proof, bytes32 root, bytes32 leaf) internal pure returns (bool) {
+        bytes32 computedHash = leaf;
 
-    for (uint256 i = 0; i < proof.length; i++) {
-      bytes32 proofElement = proof[i];
+        for (uint256 i = 0; i < proof.length; i++) {
+            bytes32 proofElement = proof[i];
 
-      if (computedHash < proofElement) {
-        // Hash(current computed hash + current element of the proof)
-        computedHash = keccak256(abi.encodePacked(computedHash, proofElement));
-      } else {
-        // Hash(current element of the proof + current computed hash)
-        computedHash = keccak256(abi.encodePacked(proofElement, computedHash));
-      }
+            if (computedHash < proofElement) {
+                // Hash(current computed hash + current element of the proof)
+                computedHash = keccak256(abi.encodePacked(computedHash, proofElement));
+            } else {
+                // Hash(current element of the proof + current computed hash)
+                computedHash = keccak256(abi.encodePacked(proofElement, computedHash));
+            }
+        }
+
+        // Check if the computed hash (root) is equal to the provided root
+        return computedHash == root;
     }
-
-    // Check if the computed hash (root) is equal to the provided root
-    return computedHash == root;
-  }
 }

contracts/drafts/Counter.sol

@@ -1,28 +0,0 @@
-pragma solidity ^0.4.24;
-
-/**
- * @title Counter
- * @author Matt Condon (@shrugs)
- * @dev Provides an incrementing uint256 id acquired by the `Counter#next` getter.
- * Use this for issuing ERC721 ids or keeping track of request ids, anything you want, really.
- *
- * Include with `using Counter for Counter.Counter;`
- * @notice Does not allow an Id of 0, which is popularly used to signify a null state in solidity.
- * Does not protect from overflows, but if you have 2^256 ids, you have other problems.
- * (But actually, it's generally impossible to increment a counter this many times, energy wise
- * so it's not something you have to worry about.)
- */
-library Counter {
-
-  struct Counter {
-    uint256 current; // default: 0
-  }
-
-  function next(Counter storage index)
-    internal
-    returns (uint256)
-  {
-    index.current += 1;
-    return index.current;
-  }
-}

contracts/drafts/Counters.sol

@@ -0,0 +1,37 @@
+pragma solidity ^0.5.2;
+
+import "../math/SafeMath.sol";
+
+/**
+ * @title Counters
+ * @author Matt Condon (@shrugs)
+ * @dev Provides counters that can only be incremented or decremented by one. This can be used e.g. to track the number
+ * of elements in a mapping, issuing ERC721 ids, or counting request ids
+ *
+ * Include with `using Counters for Counters.Counter;`
+ * Since it is not possible to overflow a 256 bit integer with increments of one, `increment` can skip the SafeMath
+ * overflow check, thereby saving gas. This does assume however correct usage, in that the underlying `_value` is never
+ * directly accessed.
+ */
+library Counters {
+    using SafeMath for uint256;
+
+    struct Counter {
+        // This variable should never be directly accessed by users of the library: interactions must be restricted to
+        // the library's function. As of Solidity v0.5.2, this cannot be enforced, though there is a proposal to add
+        // this feature: see https://github.com/ethereum/solidity/issues/4637
+        uint256 _value; // default: 0
+    }
+
+    function current(Counter storage counter) internal view returns (uint256) {
+        return counter._value;
+    }
+
+    function increment(Counter storage counter) internal {
+        counter._value += 1;
+    }
+
+    function decrement(Counter storage counter) internal {
+        counter._value = counter._value.sub(1);
+    }
+}

contracts/drafts/ERC1046/ERC20Metadata.sol

@@ -0,0 +1,27 @@
+pragma solidity ^0.5.2;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+import "../../token/ERC20/IERC20.sol";
+
+/**
+ * @title ERC-1047 Token Metadata
+ * @dev See https://eips.ethereum.org/EIPS/eip-1046
+ * @dev tokenURI must respond with a URI that implements https://eips.ethereum.org/EIPS/eip-1047
+ */
+contract ERC20Metadata is Initializable {
+    string private _tokenURI;
+
+    function initialize(string memory tokenURI_) public {
+        _setTokenURI(tokenURI_);
+    }
+
+    function tokenURI() external view returns (string memory) {
+        return _tokenURI;
+    }
+
+    function _setTokenURI(string memory tokenURI_) internal {
+        _tokenURI = tokenURI_;
+    }
+
+    uint256[50] private ______gap;
+}

contracts/drafts/ERC1046/TokenMetadata.sol

@@ -1,27 +0,0 @@
-pragma solidity ^0.4.24;
-
-import "../../token/ERC20/IERC20.sol";
-
-/**
- * @title ERC-1047 Token Metadata
- * @dev See https://eips.ethereum.org/EIPS/eip-1046
- * @dev tokenURI must respond with a URI that implements https://eips.ethereum.org/EIPS/eip-1047
- * @dev TODO - update https://github.com/OpenZeppelin/openzeppelin-solidity/blob/master/contracts/token/ERC721/IERC721.sol#L17 when 1046 is finalized
- */
-contract ERC20TokenMetadata is IERC20 {
-  function tokenURI() external view returns (string);
-}
-
-contract ERC20WithMetadata is ERC20TokenMetadata {
-  string private _tokenURI;
-
-  constructor(string tokenURI)
-    public
-  {
-    _tokenURI = tokenURI;
-  }
-
-  function tokenURI() external view returns (string) {
-    return _tokenURI;
-  }
-}

contracts/drafts/ERC20Migrator.sol

@@ -1,5 +1,6 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
 import "../token/ERC20/IERC20.sol";
 import "../token/ERC20/ERC20Mintable.sol";
 import "../token/ERC20/SafeERC20.sol";
@@ -17,13 +18,13 @@ import "../math/Math.sol";
  * OpenZeppelin's ERC20Mintable, but the only functions that are needed are
  * `isMinter(address)` and `mint(address, amount)`. The migrator will check
  * that it is a minter for the token.
- * The balance from the legacy token will be transfered to the migrator, as it
+ * The balance from the legacy token will be transferred to the migrator, as it
  * is migrated, and remain there forever.
  * Although this contract can be used in many different scenarios, the main
  * motivation was to provide a way to migrate ERC20 tokens into an upgradeable
- * version of it using ZeppelinOS. To read more about how this can be done
+ * version of it using the OpenZeppelin SDK. To read more about how this can be done
  * using this implementation, please follow the official documentation site of
- * ZeppelinOS: https://docs.zeppelinos.org/docs/erc20_onboarding.html
+ * the OpenZeppelinSDK: https://docs.zeppelinos.org/docs/erc20_onboarding.html
  * Example of usage:
  * ```
  * const migrator = await ERC20Migrator.new(legacyToken.address);
@@ -31,70 +32,73 @@ import "../math/Math.sol";
  * await migrator.beginMigration(newToken.address);
  * ```
  */
-contract ERC20Migrator {
-  using SafeERC20 for IERC20;
+contract ERC20Migrator is Initializable {
+    using SafeERC20 for IERC20;
 
-  /// Address of the old token contract
-  IERC20 private _legacyToken;
+    /// Address of the old token contract
+    IERC20 private _legacyToken;
 
-  /// Address of the new token contract
-  ERC20Mintable private _newToken;
+    /// Address of the new token contract
+    ERC20Mintable private _newToken;
 
-  /**
-   * @param legacyToken address of the old token contract
-   */
-  constructor(IERC20 legacyToken) public {
-    require(legacyToken != address(0));
-    _legacyToken = legacyToken;
-  }
+    /**
+     * @param legacyToken address of the old token contract
+     */
+    function initialize(IERC20 legacyToken) public initializer {
+        require(address(legacyToken) != address(0));
+        _legacyToken = legacyToken;
+    }
 
-  /**
-   * @dev Returns the legacy token that is being migrated.
-   */
-  function legacyToken() public view returns (IERC20) {
-    return _legacyToken;
-  }
+    /**
+     * @dev Returns the legacy token that is being migrated.
+     */
+    function legacyToken() public view returns (IERC20) {
+        return _legacyToken;
+    }
 
-  /**
-   * @dev Returns the new token to which we are migrating.
-   */
-  function newToken() public view returns (IERC20) {
-    return _newToken;
-  }
+    /**
+     * @dev Returns the new token to which we are migrating.
+     */
+    function newToken() public view returns (IERC20) {
+        return _newToken;
+    }
 
-  /**
-   * @dev Begins the migration by setting which is the new token that will be
-   * minted. This contract must be a minter for the new token.
-   * @param newToken the token that will be minted
-   */
-  function beginMigration(ERC20Mintable newToken) public {
-    require(_newToken == address(0));
-    require(newToken != address(0));
-    require(newToken.isMinter(this));
+    /**
+     * @dev Begins the migration by setting which is the new token that will be
+     * minted. This contract must be a minter for the new token.
+     * @param newToken_ the token that will be minted
+     */
+    function beginMigration(ERC20Mintable newToken_) public {
+        require(address(_newToken) == address(0));
+        require(address(newToken_) != address(0));
+        require(newToken_.isMinter(address(this)));
 
-    _newToken = newToken;
-  }
+        _newToken = newToken_;
+    }
 
-  /**
-   * @dev Transfers part of an account's balance in the old token to this
-   * contract, and mints the same amount of new tokens for that account.
-   * @param account whose tokens will be migrated
-   * @param amount amount of tokens to be migrated
-   */
-  function migrate(address account, uint256 amount) public {
-    _legacyToken.safeTransferFrom(account, this, amount);
-    _newToken.mint(account, amount);
-  }
+    /**
+     * @dev Transfers part of an account's balance in the old token to this
+     * contract, and mints the same amount of new tokens for that account.
+     * @param account whose tokens will be migrated
+     * @param amount amount of tokens to be migrated
+     */
+    function migrate(address account, uint256 amount) public {
+        require(address(_newToken) != address(0));
+        _legacyToken.safeTransferFrom(account, address(this), amount);
+        _newToken.mint(account, amount);
+    }
 
-  /**
-   * @dev Transfers all of an account's allowed balance in the old token to
-   * this contract, and mints the same amount of new tokens for that account.
-   * @param account whose tokens will be migrated
-   */
-  function migrateAll(address account) public {
-    uint256 balance = _legacyToken.balanceOf(account);
-    uint256 allowance = _legacyToken.allowance(account, this);
-    uint256 amount = Math.min(balance, allowance);
-    migrate(account, amount);
-  }
+    /**
+     * @dev Transfers all of an account's allowed balance in the old token to
+     * this contract, and mints the same amount of new tokens for that account.
+     * @param account whose tokens will be migrated
+     */
+    function migrateAll(address account) public {
+        uint256 balance = _legacyToken.balanceOf(account);
+        uint256 allowance = _legacyToken.allowance(account, address(this));
+        uint256 amount = Math.min(balance, allowance);
+        migrate(account, amount);
+    }
+
+    uint256[50] private ______gap;
 }

contracts/drafts/ERC20Snapshot.sol

@@ -0,0 +1,142 @@
+pragma solidity ^0.5.2;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+import "../math/SafeMath.sol";
+import "../utils/Arrays.sol";
+import "../drafts/Counters.sol";
+import "../token/ERC20/ERC20.sol";
+
+/**
+ * @title ERC20 token with snapshots.
+ * @dev Inspired by Jordi Baylina's MiniMeToken to record historical balances:
+ * https://github.com/Giveth/minime/blob/ea04d950eea153a04c51fa510b068b9dded390cb/contracts/MiniMeToken.sol
+ * When a snapshot is made, the balances and totalSupply at the time of the snapshot are recorded for later
+ * access.
+ *
+ * To make a snapshot, call the `snapshot` function, which will emit the `Snapshot` event and return a snapshot id.
+ * To get the total supply from a snapshot, call the function `totalSupplyAt` with the snapshot id.
+ * To get the balance of an account from a snapshot, call the `balanceOfAt` function with the snapshot id and the
+ * account address.
+ * @author Validity Labs AG <info@validitylabs.org>
+ */
+contract ERC20Snapshot is Initializable, ERC20 {
+    using SafeMath for uint256;
+    using Arrays for uint256[];
+    using Counters for Counters.Counter;
+
+    // Snapshotted values have arrays of ids and the value corresponding to that id. These could be an array of a
+    // Snapshot struct, but that would impede usage of functions that work on an array.
+    struct Snapshots {
+        uint256[] ids;
+        uint256[] values;
+    }
+
+    mapping (address => Snapshots) private _accountBalanceSnapshots;
+    Snapshots private _totalSupplySnaphots;
+
+    // Snapshot ids increase monotonically, with the first value being 1. An id of 0 is invalid.
+    Counters.Counter private _currentSnapshotId;
+
+    event Snapshot(uint256 id);
+
+    // Creates a new snapshot id. Balances are only stored in snapshots on demand: unless a snapshot was taken, a
+    // balance change will not be recorded. This means the extra added cost of storing snapshotted balances is only paid
+    // when required, but is also flexible enough that it allows for e.g. daily snapshots.
+    function snapshot() public returns (uint256) {
+        _currentSnapshotId.increment();
+
+        uint256 currentId = _currentSnapshotId.current();
+        emit Snapshot(currentId);
+        return currentId;
+    }
+
+    function balanceOfAt(address account, uint256 snapshotId) public view returns (uint256) {
+        (bool snapshotted, uint256 value) = _valueAt(snapshotId, _accountBalanceSnapshots[account]);
+
+        return snapshotted ? value : balanceOf(account);
+    }
+
+    function totalSupplyAt(uint256 snapshotId) public view returns(uint256) {
+        (bool snapshotted, uint256 value) = _valueAt(snapshotId, _totalSupplySnaphots);
+
+        return snapshotted ? value : totalSupply();
+    }
+
+    // _transfer, _mint and _burn are the only functions where the balances are modified, so it is there that the
+    // snapshots are updated. Note that the update happens _before_ the balance change, with the pre-modified value.
+    // The same is true for the total supply and _mint and _burn.
+    function _transfer(address from, address to, uint256 value) internal {
+        _updateAccountSnapshot(from);
+        _updateAccountSnapshot(to);
+
+        super._transfer(from, to, value);
+    }
+
+    function _mint(address account, uint256 value) internal {
+        _updateAccountSnapshot(account);
+        _updateTotalSupplySnapshot();
+
+        super._mint(account, value);
+    }
+
+    function _burn(address account, uint256 value) internal {
+        _updateAccountSnapshot(account);
+        _updateTotalSupplySnapshot();
+
+        super._burn(account, value);
+    }
+
+    // When a valid snapshot is queried, there are three possibilities:
+    //  a) The queried value was not modified after the snapshot was taken. Therefore, a snapshot entry was never
+    //  created for this id, and all stored snapshot ids are smaller than the requested one. The value that corresponds
+    //  to this id is the current one.
+    //  b) The queried value was modified after the snapshot was taken. Therefore, there will be an entry with the
+    //  requested id, and its value is the one to return.
+    //  c) More snapshots were created after the requested one, and the queried value was later modified. There will be
+    //  no entry for the requested id: the value that corresponds to it is that of the smallest snapshot id that is
+    //  larger than the requested one.
+    //
+    // In summary, we need to find an element in an array, returning the index of the smallest value that is larger if
+    // it is not found, unless said value doesn't exist (e.g. when all values are smaller). Arrays.findUpperBound does
+    // exactly this.
+    function _valueAt(uint256 snapshotId, Snapshots storage snapshots)
+        private view returns (bool, uint256)
+    {
+        require(snapshotId > 0);
+        require(snapshotId <= _currentSnapshotId.current());
+
+        uint256 index = snapshots.ids.findUpperBound(snapshotId);
+
+        if (index == snapshots.ids.length) {
+            return (false, 0);
+        } else {
+            return (true, snapshots.values[index]);
+        }
+    }
+
+    function _updateAccountSnapshot(address account) private {
+        _updateSnapshot(_accountBalanceSnapshots[account], balanceOf(account));
+    }
+
+    function _updateTotalSupplySnapshot() private {
+        _updateSnapshot(_totalSupplySnaphots, totalSupply());
+    }
+
+    function _updateSnapshot(Snapshots storage snapshots, uint256 currentValue) private {
+        uint256 currentId = _currentSnapshotId.current();
+        if (_lastSnapshotId(snapshots.ids) < currentId) {
+            snapshots.ids.push(currentId);
+            snapshots.values.push(currentValue);
+        }
+    }
+
+    function _lastSnapshotId(uint256[] storage ids) private view returns (uint256) {
+        if (ids.length == 0) {
+            return 0;
+        } else {
+            return ids[ids.length - 1];
+        }
+    }
+
+    uint256[50] private ______gap;
+}

contracts/drafts/SignatureBouncer.sol

@@ -1,5 +1,6 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
 import "../access/roles/SignerRole.sol";
 import "../cryptography/ECDSA.sol";
 
@@ -29,118 +30,94 @@ import "../cryptography/ECDSA.sol";
  * @notice A method that uses the `onlyValidSignatureAndData` modifier must make
  * the _signature parameter the "last" parameter. You cannot sign a message that
  * has its own signature in it so the last 128 bytes of msg.data (which
- * represents the length of the _signature data and the _signaature data itself)
+ * represents the length of the _signature data and the _signature data itself)
  * is ignored when validating. Also non fixed sized parameters make constructing
  * the data in the signature much more complex.
  * See https://ethereum.stackexchange.com/a/50616 for more details.
  */
-contract SignatureBouncer is SignerRole {
-  using ECDSA for bytes32;
+contract SignatureBouncer is Initializable, SignerRole {
+    using ECDSA for bytes32;
 
-  // Function selectors are 4 bytes long, as documented in
-  // https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector
-  uint256 private constant _METHOD_ID_SIZE = 4;
-  // Signature size is 65 bytes (tightly packed v + r + s), but gets padded to 96 bytes
-  uint256 private constant _SIGNATURE_SIZE = 96;
+    // Function selectors are 4 bytes long, as documented in
+    // https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector
+    uint256 private constant _METHOD_ID_SIZE = 4;
+    // Signature size is 65 bytes (tightly packed v + r + s), but gets padded to 96 bytes
+    uint256 private constant _SIGNATURE_SIZE = 96;
 
-  constructor() internal {}
-
-  /**
-   * @dev requires that a valid signature of a signer was provided
-   */
-  modifier onlyValidSignature(bytes signature)
-  {
-    require(_isValidSignature(msg.sender, signature));
-    _;
-  }
-
-  /**
-   * @dev requires that a valid signature with a specifed method of a signer was provided
-   */
-  modifier onlyValidSignatureAndMethod(bytes signature)
-  {
-    require(_isValidSignatureAndMethod(msg.sender, signature));
-    _;
-  }
-
-  /**
-   * @dev requires that a valid signature with a specifed method and params of a signer was provided
-   */
-  modifier onlyValidSignatureAndData(bytes signature)
-  {
-    require(_isValidSignatureAndData(msg.sender, signature));
-    _;
-  }
-
-  /**
-   * @dev is the signature of `this + sender` from a signer?
-   * @return bool
-   */
-  function _isValidSignature(address account, bytes signature)
-    internal
-    view
-    returns (bool)
-  {
-    return _isValidDataHash(
-      keccak256(abi.encodePacked(address(this), account)),
-      signature
-    );
-  }
-
-  /**
-   * @dev is the signature of `this + sender + methodId` from a signer?
-   * @return bool
-   */
-  function _isValidSignatureAndMethod(address account, bytes signature)
-    internal
-    view
-    returns (bool)
-  {
-    bytes memory data = new bytes(_METHOD_ID_SIZE);
-    for (uint i = 0; i < data.length; i++) {
-      data[i] = msg.data[i];
+    function initialize(address sender) public initializer {
+        SignerRole.initialize(sender);
     }
-    return _isValidDataHash(
-      keccak256(abi.encodePacked(address(this), account, data)),
-      signature
-    );
-  }
 
-  /**
-    * @dev is the signature of `this + sender + methodId + params(s)` from a signer?
-    * @notice the signature parameter of the method being validated must be the "last" parameter
-    * @return bool
-    */
-  function _isValidSignatureAndData(address account, bytes signature)
-    internal
-    view
-    returns (bool)
-  {
-    require(msg.data.length > _SIGNATURE_SIZE);
-    bytes memory data = new bytes(msg.data.length - _SIGNATURE_SIZE);
-    for (uint i = 0; i < data.length; i++) {
-      data[i] = msg.data[i];
+    /**
+     * @dev requires that a valid signature of a signer was provided
+     */
+    modifier onlyValidSignature(bytes memory signature) {
+        require(_isValidSignature(msg.sender, signature));
+        _;
     }
-    return _isValidDataHash(
-      keccak256(abi.encodePacked(address(this), account, data)),
-      signature
-    );
-  }
 
-  /**
-   * @dev internal function to convert a hash to an eth signed message
-   * and then recover the signature and check it against the signer role
-   * @return bool
-   */
-  function _isValidDataHash(bytes32 hash, bytes signature)
-    internal
-    view
-    returns (bool)
-  {
-    address signer = hash
-      .toEthSignedMessageHash()
-      .recover(signature);
+    /**
+     * @dev requires that a valid signature with a specified method of a signer was provided
+     */
+    modifier onlyValidSignatureAndMethod(bytes memory signature) {
+        require(_isValidSignatureAndMethod(msg.sender, signature));
+        _;
+    }
 
-    return signer != address(0) && isSigner(signer);
-  }
+    /**
+     * @dev requires that a valid signature with a specified method and params of a signer was provided
+     */
+    modifier onlyValidSignatureAndData(bytes memory signature) {
+        require(_isValidSignatureAndData(msg.sender, signature));
+        _;
+    }
+
+    /**
+     * @dev is the signature of `this + account` from a signer?
+     * @return bool
+     */
+    function _isValidSignature(address account, bytes memory signature) internal view returns (bool) {
+        return _isValidDataHash(keccak256(abi.encodePacked(address(this), account)), signature);
+    }
+
+    /**
+     * @dev is the signature of `this + account + methodId` from a signer?
+     * @return bool
+     */
+    function _isValidSignatureAndMethod(address account, bytes memory signature) internal view returns (bool) {
+        bytes memory data = new bytes(_METHOD_ID_SIZE);
+        for (uint i = 0; i < data.length; i++) {
+            data[i] = msg.data[i];
+        }
+        return _isValidDataHash(keccak256(abi.encodePacked(address(this), account, data)), signature);
+    }
+
+    /**
+     * @dev is the signature of `this + account + methodId + params(s)` from a signer?
+     * @notice the signature parameter of the method being validated must be the "last" parameter
+     * @return bool
+     */
+    function _isValidSignatureAndData(address account, bytes memory signature) internal view returns (bool) {
+        require(msg.data.length > _SIGNATURE_SIZE);
+
+        bytes memory data = new bytes(msg.data.length - _SIGNATURE_SIZE);
+        for (uint i = 0; i < data.length; i++) {
+            data[i] = msg.data[i];
+        }
+
+        return _isValidDataHash(keccak256(abi.encodePacked(address(this), account, data)), signature);
+    }
+
+    /**
+     * @dev internal function to convert a hash to an eth signed message
+     * and then recover the signature and check it against the signer role
+     * @return bool
+     */
+    function _isValidDataHash(bytes32 hash, bytes memory signature) internal view returns (bool) {
+        address signer = hash.toEthSignedMessageHash().recover(signature);
+
+        return signer != address(0) && isSigner(signer);
+    }
+
+    uint256[50] private ______gap;
 }

contracts/drafts/SignedSafeMath.sol

@@ -0,0 +1,60 @@
+pragma solidity ^0.5.2;
+
+/**
+ * @title SignedSafeMath
+ * @dev Signed math operations with safety checks that revert on error
+ */
+library SignedSafeMath {
+    int256 constant private INT256_MIN = -2**255;
+
+    /**
+     * @dev Multiplies two signed integers, reverts on overflow.
+     */
+    function mul(int256 a, int256 b) internal pure returns (int256) {
+        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
+        // benefit is lost if 'b' is also tested.
+        // See: https://github.com/OpenZeppelin/openzeppelin-solidity/pull/522
+        if (a == 0) {
+            return 0;
+        }
+
+        require(!(a == -1 && b == INT256_MIN)); // This is the only case of overflow not detected by the check below
+
+        int256 c = a * b;
+        require(c / a == b);
+
+        return c;
+    }
+
+    /**
+     * @dev Integer division of two signed integers truncating the quotient, reverts on division by zero.
+     */
+    function div(int256 a, int256 b) internal pure returns (int256) {
+        require(b != 0); // Solidity only automatically asserts when dividing by 0
+        require(!(b == -1 && a == INT256_MIN)); // This is the only case of overflow
+
+        int256 c = a / b;
+
+        return c;
+    }
+
+    /**
+     * @dev Subtracts two signed integers, reverts on overflow.
+     */
+    function sub(int256 a, int256 b) internal pure returns (int256) {
+        int256 c = a - b;
+        require((b >= 0 && c <= a) || (b < 0 && c > a));
+
+        return c;
+    }
+
+    /**
+     * @dev Adds two signed integers, reverts on overflow.
+     */
+    function add(int256 a, int256 b) internal pure returns (int256) {
+        int256 c = a + b;
+        require((b >= 0 && c >= a) || (b < 0 && c < a));
+
+        return c;
+    }
+}

contracts/drafts/TokenVesting.sol

@@ -1,7 +1,6 @@
-/* solium-disable security/no-block-members */
-
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
 import "../token/ERC20/SafeERC20.sol";
 import "../ownership/Ownable.sol";
 import "../math/SafeMath.sol";
@@ -12,164 +11,167 @@ import "../math/SafeMath.sol";
  * typical vesting scheme, with a cliff and vesting period. Optionally revocable by the
  * owner.
  */
-contract TokenVesting is Ownable {
-  using SafeMath for uint256;
-  using SafeERC20 for IERC20;
+contract TokenVesting is Initializable, Ownable {
+    // The vesting schedule is time-based (i.e. using block timestamps as opposed to e.g. block numbers), and is
+    // therefore sensitive to timestamp manipulation (which is something miners can do, to a certain degree). Therefore,
+    // it is recommended to avoid using short time durations (less than a minute). Typical vesting schemes, with a
+    // cliff period of a year and a duration of four years, are safe to use.
+    // solhint-disable not-rely-on-time
 
-  event TokensReleased(address token, uint256 amount);
-  event TokenVestingRevoked(address token);
+    using SafeMath for uint256;
+    using SafeERC20 for IERC20;
 
-  // beneficiary of tokens after they are released
-  address private _beneficiary;
+    event TokensReleased(address token, uint256 amount);
+    event TokenVestingRevoked(address token);
 
-  uint256 private _cliff;
-  uint256 private _start;
-  uint256 private _duration;
+    // beneficiary of tokens after they are released
+    address private _beneficiary;
 
-  bool private _revocable;
+    // Durations and timestamps are expressed in UNIX time, the same units as block.timestamp.
+    uint256 private _cliff;
+    uint256 private _start;
+    uint256 private _duration;
 
-  mapping (address => uint256) private _released;
-  mapping (address => bool) private _revoked;
+    bool private _revocable;
 
-  /**
-   * @dev Creates a vesting contract that vests its balance of any ERC20 token to the
-   * beneficiary, gradually in a linear fashion until start + duration. By then all
-   * of the balance will have vested.
-   * @param beneficiary address of the beneficiary to whom vested tokens are transferred
-   * @param cliffDuration duration in seconds of the cliff in which tokens will begin to vest
-   * @param start the time (as Unix time) at which point vesting starts
-   * @param duration duration in seconds of the period in which the tokens will vest
-   * @param revocable whether the vesting is revocable or not
-   */
-  constructor(
-    address beneficiary,
-    uint256 start,
-    uint256 cliffDuration,
-    uint256 duration,
-    bool revocable
-  )
-    public
-  {
-    require(beneficiary != address(0));
-    require(cliffDuration <= duration);
-    require(duration > 0);
-    require(start.add(duration) > block.timestamp);
+    mapping (address => uint256) private _released;
+    mapping (address => bool) private _revoked;
 
-    _beneficiary = beneficiary;
-    _revocable = revocable;
-    _duration = duration;
-    _cliff = start.add(cliffDuration);
-    _start = start;
-  }
+    /**
+     * @dev Creates a vesting contract that vests its balance of any ERC20 token to the
+     * beneficiary, gradually in a linear fashion until start + duration. By then all
+     * of the balance will have vested.
+     * @param beneficiary address of the beneficiary to whom vested tokens are transferred
+     * @param cliffDuration duration in seconds of the cliff in which tokens will begin to vest
+     * @param start the time (as Unix time) at which point vesting starts
+     * @param duration duration in seconds of the period in which the tokens will vest
+     * @param revocable whether the vesting is revocable or not
+     */
+    function initialize(address beneficiary, uint256 start, uint256 cliffDuration, uint256 duration, bool revocable, address sender) public initializer {
+        Ownable.initialize(sender);
 
-  /**
-   * @return the beneficiary of the tokens.
-   */
-  function beneficiary() public view returns(address) {
-    return _beneficiary;
-  }
+        require(beneficiary != address(0));
+        require(cliffDuration <= duration);
+        require(duration > 0);
+        require(start.add(duration) > block.timestamp);
 
-  /**
-   * @return the cliff time of the token vesting.
-   */
-  function cliff() public view returns(uint256) {
-    return _cliff;
-  }
-
-  /**
-   * @return the start time of the token vesting.
-   */
-  function start() public view returns(uint256) {
-    return _start;
-  }
-
-  /**
-   * @return the duration of the token vesting.
-   */
-  function duration() public view returns(uint256) {
-    return _duration;
-  }
-
-  /**
-   * @return true if the vesting is revocable.
-   */
-  function revocable() public view returns(bool) {
-    return _revocable;
-  }
-
-  /**
-   * @return the amount of the token released.
-   */
-  function released(address token) public view returns(uint256) {
-    return _released[token];
-  }
-
-  /**
-   * @return true if the token is revoked.
-   */
-  function revoked(address token) public view returns(bool) {
-    return _revoked[token];
-  }
-
-  /**
-   * @notice Transfers vested tokens to beneficiary.
-   * @param token ERC20 token which is being vested
-   */
-  function release(IERC20 token) public {
-    uint256 unreleased = _releasableAmount(token);
-
-    require(unreleased > 0);
-
-    _released[token] = _released[token].add(unreleased);
-
-    token.safeTransfer(_beneficiary, unreleased);
-
-    emit TokensReleased(token, unreleased);
-  }
-
-  /**
-   * @notice Allows the owner to revoke the vesting. Tokens already vested
-   * remain in the contract, the rest are returned to the owner.
-   * @param token ERC20 token which is being vested
-   */
-  function revoke(IERC20 token) public onlyOwner {
-    require(_revocable);
-    require(!_revoked[token]);
-
-    uint256 balance = token.balanceOf(address(this));
-
-    uint256 unreleased = _releasableAmount(token);
-    uint256 refund = balance.sub(unreleased);
-
-    _revoked[token] = true;
-
-    token.safeTransfer(owner(), refund);
-
-    emit TokenVestingRevoked(token);
-  }
-
-  /**
-   * @dev Calculates the amount that has already vested but hasn't been released yet.
-   * @param token ERC20 token which is being vested
-   */
-  function _releasableAmount(IERC20 token) private view returns (uint256) {
-    return _vestedAmount(token).sub(_released[token]);
-  }
-
-  /**
-   * @dev Calculates the amount that has already vested.
-   * @param token ERC20 token which is being vested
-   */
-  function _vestedAmount(IERC20 token) private view returns (uint256) {
-    uint256 currentBalance = token.balanceOf(this);
-    uint256 totalBalance = currentBalance.add(_released[token]);
-
-    if (block.timestamp < _cliff) {
-      return 0;
-    } else if (block.timestamp >= _start.add(_duration) || _revoked[token]) {
-      return totalBalance;
-    } else {
-      return totalBalance.mul(block.timestamp.sub(_start)).div(_duration);
+        _beneficiary = beneficiary;
+        _revocable = revocable;
+        _duration = duration;
+        _cliff = start.add(cliffDuration);
+        _start = start;
     }
-  }
+
+    /**
+     * @return the beneficiary of the tokens.
+     */
+    function beneficiary() public view returns (address) {
+        return _beneficiary;
+    }
+
+    /**
+     * @return the cliff time of the token vesting.
+     */
+    function cliff() public view returns (uint256) {
+        return _cliff;
+    }
+
+    /**
+     * @return the start time of the token vesting.
+     */
+    function start() public view returns (uint256) {
+        return _start;
+    }
+
+    /**
+     * @return the duration of the token vesting.
+     */
+    function duration() public view returns (uint256) {
+        return _duration;
+    }
+
+    /**
+     * @return true if the vesting is revocable.
+     */
+    function revocable() public view returns (bool) {
+        return _revocable;
+    }
+
+    /**
+     * @return the amount of the token released.
+     */
+    function released(address token) public view returns (uint256) {
+        return _released[token];
+    }
+
+    /**
+     * @return true if the token is revoked.
+     */
+    function revoked(address token) public view returns (bool) {
+        return _revoked[token];
+    }
+
+    /**
+     * @notice Transfers vested tokens to beneficiary.
+     * @param token ERC20 token which is being vested
+     */
+    function release(IERC20 token) public {
+        uint256 unreleased = _releasableAmount(token);
+
+        require(unreleased > 0);
+
+        _released[address(token)] = _released[address(token)].add(unreleased);
+
+        token.safeTransfer(_beneficiary, unreleased);
+
+        emit TokensReleased(address(token), unreleased);
+    }
+
+    /**
+     * @notice Allows the owner to revoke the vesting. Tokens already vested
+     * remain in the contract, the rest are returned to the owner.
+     * @param token ERC20 token which is being vested
+     */
+    function revoke(IERC20 token) public onlyOwner {
+        require(_revocable);
+        require(!_revoked[address(token)]);
+
+        uint256 balance = token.balanceOf(address(this));
+
+        uint256 unreleased = _releasableAmount(token);
+        uint256 refund = balance.sub(unreleased);
+
+        _revoked[address(token)] = true;
+
+        token.safeTransfer(owner(), refund);
+
+        emit TokenVestingRevoked(address(token));
+    }
+
+    /**
+     * @dev Calculates the amount that has already vested but hasn't been released yet.
+     * @param token ERC20 token which is being vested
+     */
+    function _releasableAmount(IERC20 token) private view returns (uint256) {
+        return _vestedAmount(token).sub(_released[address(token)]);
+    }
+
+    /**
+     * @dev Calculates the amount that has already vested.
+     * @param token ERC20 token which is being vested
+     */
+    function _vestedAmount(IERC20 token) private view returns (uint256) {
+        uint256 currentBalance = token.balanceOf(address(this));
+        uint256 totalBalance = currentBalance.add(_released[address(token)]);
+
+        if (block.timestamp < _cliff) {
+            return 0;
+        } else if (block.timestamp >= _start.add(_duration) || _revoked[address(token)]) {
+            return totalBalance;
+        } else {
+            return totalBalance.mul(block.timestamp.sub(_start)).div(_duration);
+        }
+    }
+
+    uint256[50] private ______gap;
 }

contracts/examples/SampleCrowdsale.sol

@@ -1,5 +1,6 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
 import "../crowdsale/validation/CappedCrowdsale.sol";
 import "../crowdsale/distribution/RefundableCrowdsale.sol";
 import "../crowdsale/emission/MintedCrowdsale.sol";
@@ -11,8 +12,13 @@ import "../token/ERC20/ERC20Detailed.sol";
  * @dev Very simple ERC20 Token that can be minted.
  * It is meant to be used in a crowdsale contract.
  */
-contract SampleCrowdsaleToken is ERC20Mintable, ERC20Detailed {
-  constructor() public ERC20Detailed("Sample Crowdsale Token", "SCT", 18) {}
+contract SampleCrowdsaleToken is Initializable, ERC20Mintable, ERC20Detailed {
+    function initialize(address sender) public initializer {
+        ERC20Mintable.initialize(sender);
+        ERC20Detailed.initialize("Sample Crowdsale Token", "SCT", 18);
+    }
+
+    uint256[50] private ______gap;
 }
 
 /**
@@ -28,30 +34,29 @@ contract SampleCrowdsaleToken is ERC20Mintable, ERC20Detailed {
  * After adding multiple features it's good practice to run integration tests
  * to ensure that subcontracts works together as intended.
  */
-// XXX There doesn't seem to be a way to split this line that keeps solium
-// happy. See:
-// https://github.com/duaraghav8/Solium/issues/205
-// --elopio - 2018-05-10
-// solium-disable-next-line max-len
-contract SampleCrowdsale is CappedCrowdsale, RefundableCrowdsale, MintedCrowdsale {
+contract SampleCrowdsale is Initializable, Crowdsale, CappedCrowdsale, RefundableCrowdsale, MintedCrowdsale {
 
-  constructor(
-    uint256 openingTime,
-    uint256 closingTime,
-    uint256 rate,
-    address wallet,
-    uint256 cap,
-    ERC20Mintable token,
-    uint256 goal
-  )
-    public
-    Crowdsale(rate, wallet, token)
-    CappedCrowdsale(cap)
-    TimedCrowdsale(openingTime, closingTime)
-    RefundableCrowdsale(goal)
-  {
-    //As goal needs to be met for a successful crowdsale
-    //the value needs to less or equal than a cap which is limit for accepted funds
-    require(goal <= cap);
-  }
+    function initialize(
+        uint256 openingTime,
+        uint256 closingTime,
+        uint256 rate,
+        address payable wallet,
+        uint256 cap,
+        ERC20Mintable token,
+        uint256 goal
+    )
+        public
+        initializer
+    {
+        Crowdsale.initialize(rate, wallet, token);
+        CappedCrowdsale.initialize(cap);
+        TimedCrowdsale.initialize(openingTime, closingTime);
+        RefundableCrowdsale.initialize(goal);
+
+        //As goal needs to be met for a successful crowdsale
+        //the value needs to less or equal than a cap which is limit for accepted funds
+        require(goal <= cap);
+    }
+
+    uint256[50] private ______gap;
 }

contracts/examples/SimpleToken.sol

@@ -1,6 +1,8 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
 import "../token/ERC20/ERC20.sol";
+import "../token/ERC20/ERC20Detailed.sol";
 
 /**
  * @title SimpleToken
@@ -8,19 +10,17 @@ import "../token/ERC20/ERC20.sol";
  * Note they can later distribute these tokens as they wish using `transfer` and other
  * `ERC20` functions.
  */
-contract SimpleToken is ERC20 {
+contract SimpleToken is Initializable, ERC20, ERC20Detailed {
+    uint8 public constant DECIMALS = 18;
+    uint256 public constant INITIAL_SUPPLY = 10000 * (10 ** uint256(DECIMALS));
 
-  string public constant name = "SimpleToken";
-  string public constant symbol = "SIM";
-  uint8 public constant decimals = 18;
-
-  uint256 public constant INITIAL_SUPPLY = 10000 * (10 ** uint256(decimals));
-
-  /**
-   * @dev Constructor that gives msg.sender all of existing tokens.
-   */
-  constructor() public {
-    _mint(msg.sender, INITIAL_SUPPLY);
-  }
+    /**
+     * @dev Constructor that gives msg.sender all of existing tokens.
+     */
+    function initialize(address sender) public initializer {
+        ERC20Detailed.initialize("SimpleToken", "SIM", DECIMALS);
+        _mint(sender, INITIAL_SUPPLY);
+    }
 
+    uint256[50] private ______gap;
 }

contracts/introspection/ERC165.sol

@@ -1,5 +1,6 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
 import "./IERC165.sol";
 
 /**
@@ -7,47 +8,40 @@ import "./IERC165.sol";
  * @author Matt Condon (@shrugs)
  * @dev Implements ERC165 using a lookup table.
  */
-contract ERC165 is IERC165 {
+contract ERC165 is Initializable, IERC165 {
+    bytes4 private constant _INTERFACE_ID_ERC165 = 0x01ffc9a7;
+    /*
+     * 0x01ffc9a7 ===
+     *     bytes4(keccak256('supportsInterface(bytes4)'))
+     */
 
-  bytes4 private constant _InterfaceId_ERC165 = 0x01ffc9a7;
-  /**
-   * 0x01ffc9a7 ===
-   *   bytes4(keccak256('supportsInterface(bytes4)'))
-   */
+    /**
+     * @dev a mapping of interface id to whether or not it's supported
+     */
+    mapping(bytes4 => bool) private _supportedInterfaces;
 
-  /**
-   * @dev a mapping of interface id to whether or not it's supported
-   */
-  mapping(bytes4 => bool) private _supportedInterfaces;
+    /**
+     * @dev A contract implementing SupportsInterfaceWithLookup
+     * implement ERC165 itself
+     */
+    function initialize() public initializer {
+        _registerInterface(_INTERFACE_ID_ERC165);
+    }
 
-  /**
-   * @dev A contract implementing SupportsInterfaceWithLookup
-   * implement ERC165 itself
-   */
-  constructor()
-    internal
-  {
-    _registerInterface(_InterfaceId_ERC165);
-  }
+    /**
+     * @dev implement supportsInterface(bytes4) using a lookup table
+     */
+    function supportsInterface(bytes4 interfaceId) public view returns (bool) {
+        return _supportedInterfaces[interfaceId];
+    }
 
-  /**
-   * @dev implement supportsInterface(bytes4) using a lookup table
-   */
-  function supportsInterface(bytes4 interfaceId)
-    external
-    view
-    returns (bool)
-  {
-    return _supportedInterfaces[interfaceId];
-  }
+    /**
+     * @dev internal method for registering an interface
+     */
+    function _registerInterface(bytes4 interfaceId) internal {
+        require(interfaceId != 0xffffffff);
+        _supportedInterfaces[interfaceId] = true;
+    }
 
-  /**
-   * @dev internal method for registering an interface
-   */
-  function _registerInterface(bytes4 interfaceId)
-    internal
-  {
-    require(interfaceId != 0xffffffff);
-    _supportedInterfaces[interfaceId] = true;
-  }
+    uint256[50] private ______gap;
 }

contracts/introspection/ERC165Checker.sol

@@ -1,146 +1,123 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
 /**
  * @title ERC165Checker
  * @dev Use `using ERC165Checker for address`; to include this library
- * https://github.com/ethereum/EIPs/blob/master/EIPS/eip-165.md
+ * https://eips.ethereum.org/EIPS/eip-165
  */
 library ERC165Checker {
-  // As per the EIP-165 spec, no interface should ever match 0xffffffff
-  bytes4 private constant _InterfaceId_Invalid = 0xffffffff;
+    // As per the EIP-165 spec, no interface should ever match 0xffffffff
+    bytes4 private constant _INTERFACE_ID_INVALID = 0xffffffff;
 
-  bytes4 private constant _InterfaceId_ERC165 = 0x01ffc9a7;
-  /**
-   * 0x01ffc9a7 ===
-   *   bytes4(keccak256('supportsInterface(bytes4)'))
-   */
+    bytes4 private constant _INTERFACE_ID_ERC165 = 0x01ffc9a7;
+    /*
+     * 0x01ffc9a7 ===
+     *     bytes4(keccak256('supportsInterface(bytes4)'))
+     */
 
-  /**
-   * @notice Query if a contract supports ERC165
-   * @param account The address of the contract to query for support of ERC165
-   * @return true if the contract at account implements ERC165
-   */
-  function _supportsERC165(address account)
-    internal
-    view
-    returns (bool)
-  {
-    // Any contract that implements ERC165 must explicitly indicate support of
-    // InterfaceId_ERC165 and explicitly indicate non-support of InterfaceId_Invalid
-    return _supportsERC165Interface(account, _InterfaceId_ERC165) &&
-      !_supportsERC165Interface(account, _InterfaceId_Invalid);
-  }
-
-  /**
-   * @notice Query if a contract implements an interface, also checks support of ERC165
-   * @param account The address of the contract to query for support of an interface
-   * @param interfaceId The interface identifier, as specified in ERC-165
-   * @return true if the contract at account indicates support of the interface with
-   * identifier interfaceId, false otherwise
-   * @dev Interface identification is specified in ERC-165.
-   */
-  function _supportsInterface(address account, bytes4 interfaceId)
-    internal
-    view
-    returns (bool)
-  {
-    // query support of both ERC165 as per the spec and support of _interfaceId
-    return _supportsERC165(account) &&
-      _supportsERC165Interface(account, interfaceId);
-  }
-
-  /**
-   * @notice Query if a contract implements interfaces, also checks support of ERC165
-   * @param account The address of the contract to query for support of an interface
-   * @param interfaceIds A list of interface identifiers, as specified in ERC-165
-   * @return true if the contract at account indicates support all interfaces in the
-   * interfaceIds list, false otherwise
-   * @dev Interface identification is specified in ERC-165.
-   */
-  function _supportsAllInterfaces(address account, bytes4[] interfaceIds)
-    internal
-    view
-    returns (bool)
-  {
-    // query support of ERC165 itself
-    if (!_supportsERC165(account)) {
-      return false;
+    /**
+     * @notice Query if a contract supports ERC165
+     * @param account The address of the contract to query for support of ERC165
+     * @return true if the contract at account implements ERC165
+     */
+    function _supportsERC165(address account) internal view returns (bool) {
+        // Any contract that implements ERC165 must explicitly indicate support of
+        // InterfaceId_ERC165 and explicitly indicate non-support of InterfaceId_Invalid
+        return _supportsERC165Interface(account, _INTERFACE_ID_ERC165) &&
+            !_supportsERC165Interface(account, _INTERFACE_ID_INVALID);
     }
 
-    // query support of each interface in _interfaceIds
-    for (uint256 i = 0; i < interfaceIds.length; i++) {
-      if (!_supportsERC165Interface(account, interfaceIds[i])) {
-        return false;
-      }
+    /**
+     * @notice Query if a contract implements an interface, also checks support of ERC165
+     * @param account The address of the contract to query for support of an interface
+     * @param interfaceId The interface identifier, as specified in ERC-165
+     * @return true if the contract at account indicates support of the interface with
+     * identifier interfaceId, false otherwise
+     * @dev Interface identification is specified in ERC-165.
+     */
+    function _supportsInterface(address account, bytes4 interfaceId) internal view returns (bool) {
+        // query support of both ERC165 as per the spec and support of _interfaceId
+        return _supportsERC165(account) &&
+            _supportsERC165Interface(account, interfaceId);
     }
 
-    // all interfaces supported
-    return true;
-  }
+    /**
+     * @notice Query if a contract implements interfaces, also checks support of ERC165
+     * @param account The address of the contract to query for support of an interface
+     * @param interfaceIds A list of interface identifiers, as specified in ERC-165
+     * @return true if the contract at account indicates support all interfaces in the
+     * interfaceIds list, false otherwise
+     * @dev Interface identification is specified in ERC-165.
+     */
+    function _supportsAllInterfaces(address account, bytes4[] memory interfaceIds) internal view returns (bool) {
+        // query support of ERC165 itself
+        if (!_supportsERC165(account)) {
+            return false;
+        }
 
-  /**
-   * @notice Query if a contract implements an interface, does not check ERC165 support
-   * @param account The address of the contract to query for support of an interface
-   * @param interfaceId The interface identifier, as specified in ERC-165
-   * @return true if the contract at account indicates support of the interface with
-   * identifier interfaceId, false otherwise
-   * @dev Assumes that account contains a contract that supports ERC165, otherwise
-   * the behavior of this method is undefined. This precondition can be checked
-   * with the `supportsERC165` method in this library.
-   * Interface identification is specified in ERC-165.
-   */
-  function _supportsERC165Interface(address account, bytes4 interfaceId)
-    private
-    view
-    returns (bool)
-  {
-    // success determines whether the staticcall succeeded and result determines
-    // whether the contract at account indicates support of _interfaceId
-    (bool success, bool result) = _callERC165SupportsInterface(
-      account, interfaceId);
+        // query support of each interface in _interfaceIds
+        for (uint256 i = 0; i < interfaceIds.length; i++) {
+            if (!_supportsERC165Interface(account, interfaceIds[i])) {
+                return false;
+            }
+        }
 
-    return (success && result);
-  }
-
-  /**
-   * @notice Calls the function with selector 0x01ffc9a7 (ERC165) and suppresses throw
-   * @param account The address of the contract to query for support of an interface
-   * @param interfaceId The interface identifier, as specified in ERC-165
-   * @return success true if the STATICCALL succeeded, false otherwise
-   * @return result true if the STATICCALL succeeded and the contract at account
-   * indicates support of the interface with identifier interfaceId, false otherwise
-   */
-  function _callERC165SupportsInterface(
-    address account,
-    bytes4 interfaceId
-  )
-    private
-    view
-    returns (bool success, bool result)
-  {
-    bytes memory encodedParams = abi.encodeWithSelector(
-      _InterfaceId_ERC165,
-      interfaceId
-    );
-
-    // solium-disable-next-line security/no-inline-assembly
-    assembly {
-      let encodedParams_data := add(0x20, encodedParams)
-      let encodedParams_size := mload(encodedParams)
-
-      let output := mload(0x40)  // Find empty storage location using "free memory pointer"
-      mstore(output, 0x0)
-
-      success := staticcall(
-        30000,                 // 30k gas
-        account,              // To addr
-        encodedParams_data,
-        encodedParams_size,
-        output,
-        0x20                   // Outputs are 32 bytes long
-      )
-
-      result := mload(output)  // Load the result
+        // all interfaces supported
+        return true;
+    }
+
+    /**
+     * @notice Query if a contract implements an interface, does not check ERC165 support
+     * @param account The address of the contract to query for support of an interface
+     * @param interfaceId The interface identifier, as specified in ERC-165
+     * @return true if the contract at account indicates support of the interface with
+     * identifier interfaceId, false otherwise
+     * @dev Assumes that account contains a contract that supports ERC165, otherwise
+     * the behavior of this method is undefined. This precondition can be checked
+     * with the `supportsERC165` method in this library.
+     * Interface identification is specified in ERC-165.
+     */
+    function _supportsERC165Interface(address account, bytes4 interfaceId) private view returns (bool) {
+        // success determines whether the staticcall succeeded and result determines
+        // whether the contract at account indicates support of _interfaceId
+        (bool success, bool result) = _callERC165SupportsInterface(account, interfaceId);
+
+        return (success && result);
+    }
+
+    /**
+     * @notice Calls the function with selector 0x01ffc9a7 (ERC165) and suppresses throw
+     * @param account The address of the contract to query for support of an interface
+     * @param interfaceId The interface identifier, as specified in ERC-165
+     * @return success true if the STATICCALL succeeded, false otherwise
+     * @return result true if the STATICCALL succeeded and the contract at account
+     * indicates support of the interface with identifier interfaceId, false otherwise
+     */
+    function _callERC165SupportsInterface(address account, bytes4 interfaceId)
+        private
+        view
+        returns (bool success, bool result)
+    {
+        bytes memory encodedParams = abi.encodeWithSelector(_INTERFACE_ID_ERC165, interfaceId);
+
+        // solhint-disable-next-line no-inline-assembly
+        assembly {
+            let encodedParams_data := add(0x20, encodedParams)
+            let encodedParams_size := mload(encodedParams)
+
+            let output := mload(0x40)    // Find empty storage location using "free memory pointer"
+            mstore(output, 0x0)
+
+            success := staticcall(
+                30000,                   // 30k gas
+                account,                 // To addr
+                encodedParams_data,
+                encodedParams_size,
+                output,
+                0x20                     // Outputs are 32 bytes long
+            )
+
+            result := mload(output)      // Load the result
+        }
     }
-  }
 }

contracts/introspection/IERC165.sol

@@ -1,19 +1,15 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
 /**
  * @title IERC165
- * @dev https://github.com/ethereum/EIPs/blob/master/EIPS/eip-165.md
+ * @dev https://eips.ethereum.org/EIPS/eip-165
  */
 interface IERC165 {
-
-  /**
-   * @notice Query if a contract implements an interface
-   * @param interfaceId The interface identifier, as specified in ERC-165
-   * @dev Interface identification is specified in ERC-165. This function
-   * uses less than 30,000 gas.
-   */
-  function supportsInterface(bytes4 interfaceId)
-    external
-    view
-    returns (bool);
+    /**
+     * @notice Query if a contract implements an interface
+     * @param interfaceId The interface identifier, as specified in ERC-165
+     * @dev Interface identification is specified in ERC-165. This function
+     * uses less than 30,000 gas.
+     */
+    function supportsInterface(bytes4 interfaceId) external view returns (bool);
 }

contracts/lifecycle/Pausable.sol

@@ -1,57 +1,62 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
 import "../access/roles/PauserRole.sol";
 
 /**
  * @title Pausable
  * @dev Base contract which allows children to implement an emergency stop mechanism.
  */
-contract Pausable is PauserRole {
-  event Paused(address account);
-  event Unpaused(address account);
+contract Pausable is Initializable, PauserRole {
+    event Paused(address account);
+    event Unpaused(address account);
 
-  bool private _paused;
+    bool private _paused;
 
-  constructor() internal {
-    _paused = false;
-  }
+    function initialize(address sender) public initializer {
+        PauserRole.initialize(sender);
 
-  /**
-   * @return true if the contract is paused, false otherwise.
-   */
-  function paused() public view returns(bool) {
-    return _paused;
-  }
+        _paused = false;
+    }
 
-  /**
-   * @dev Modifier to make a function callable only when the contract is not paused.
-   */
-  modifier whenNotPaused() {
-    require(!_paused);
-    _;
-  }
+    /**
+     * @return true if the contract is paused, false otherwise.
+     */
+    function paused() public view returns (bool) {
+        return _paused;
+    }
 
-  /**
-   * @dev Modifier to make a function callable only when the contract is paused.
-   */
-  modifier whenPaused() {
-    require(_paused);
-    _;
-  }
+    /**
+     * @dev Modifier to make a function callable only when the contract is not paused.
+     */
+    modifier whenNotPaused() {
+        require(!_paused);
+        _;
+    }
 
-  /**
-   * @dev called by the owner to pause, triggers stopped state
-   */
-  function pause() public onlyPauser whenNotPaused {
-    _paused = true;
-    emit Paused(msg.sender);
-  }
+    /**
+     * @dev Modifier to make a function callable only when the contract is paused.
+     */
+    modifier whenPaused() {
+        require(_paused);
+        _;
+    }
 
-  /**
-   * @dev called by the owner to unpause, returns to normal state
-   */
-  function unpause() public onlyPauser whenPaused {
-    _paused = false;
-    emit Unpaused(msg.sender);
-  }
+    /**
+     * @dev called by the owner to pause, triggers stopped state
+     */
+    function pause() public onlyPauser whenNotPaused {
+        _paused = true;
+        emit Paused(msg.sender);
+    }
+
+    /**
+     * @dev called by the owner to unpause, returns to normal state
+     */
+    function unpause() public onlyPauser whenPaused {
+        _paused = false;
+        emit Unpaused(msg.sender);
+    }
+
+    uint256[50] private ______gap;
 }

contracts/math/Math.sol

@@ -1,31 +1,31 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
 /**
  * @title Math
  * @dev Assorted math operations
  */
 library Math {
-  /**
-  * @dev Returns the largest of two numbers.
-  */
-  function max(uint256 a, uint256 b) internal pure returns (uint256) {
-    return a >= b ? a : b;
-  }
+    /**
+     * @dev Returns the largest of two numbers.
+     */
+    function max(uint256 a, uint256 b) internal pure returns (uint256) {
+        return a >= b ? a : b;
+    }
 
-  /**
-  * @dev Returns the smallest of two numbers.
-  */
-  function min(uint256 a, uint256 b) internal pure returns (uint256) {
-    return a < b ? a : b;
-  }
+    /**
+     * @dev Returns the smallest of two numbers.
+     */
+    function min(uint256 a, uint256 b) internal pure returns (uint256) {
+        return a < b ? a : b;
+    }
 
-  /**
-  * @dev Calculates the average of two numbers. Since these are integers,
-  * averages of an even and odd number cannot be represented, and will be
-  * rounded down.
-  */
-  function average(uint256 a, uint256 b) internal pure returns (uint256) {
-    // (a + b) / 2 can overflow, so we distribute
-    return (a / 2) + (b / 2) + ((a % 2 + b % 2) / 2);
-  }
+    /**
+     * @dev Calculates the average of two numbers. Since these are integers,
+     * averages of an even and odd number cannot be represented, and will be
+     * rounded down.
+     */
+    function average(uint256 a, uint256 b) internal pure returns (uint256) {
+        // (a + b) / 2 can overflow, so we distribute
+        return (a / 2) + (b / 2) + ((a % 2 + b % 2) / 2);
+    }
 }

contracts/math/SafeMath.sol

@@ -1,65 +1,65 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
 /**
  * @title SafeMath
- * @dev Math operations with safety checks that revert on error
+ * @dev Unsigned math operations with safety checks that revert on error
  */
 library SafeMath {
+    /**
+     * @dev Multiplies two unsigned integers, reverts on overflow.
+     */
+    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
+        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
+        // benefit is lost if 'b' is also tested.
+        // See: https://github.com/OpenZeppelin/openzeppelin-solidity/pull/522
+        if (a == 0) {
+            return 0;
+        }
 
-  /**
-  * @dev Multiplies two numbers, reverts on overflow.
-  */
-  function mul(uint256 a, uint256 b) internal pure returns (uint256) {
-    // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
-    // benefit is lost if 'b' is also tested.
-    // See: https://github.com/OpenZeppelin/openzeppelin-solidity/pull/522
-    if (a == 0) {
-      return 0;
+        uint256 c = a * b;
+        require(c / a == b);
+
+        return c;
     }
 
-    uint256 c = a * b;
-    require(c / a == b);
+    /**
+     * @dev Integer division of two unsigned integers truncating the quotient, reverts on division by zero.
+     */
+    function div(uint256 a, uint256 b) internal pure returns (uint256) {
+        // Solidity only automatically asserts when dividing by 0
+        require(b > 0);
+        uint256 c = a / b;
+        // assert(a == b * c + a % b); // There is no case in which this doesn't hold
 
-    return c;
-  }
+        return c;
+    }
 
-  /**
-  * @dev Integer division of two numbers truncating the quotient, reverts on division by zero.
-  */
-  function div(uint256 a, uint256 b) internal pure returns (uint256) {
-    require(b > 0); // Solidity only automatically asserts when dividing by 0
-    uint256 c = a / b;
-    // assert(a == b * c + a % b); // There is no case in which this doesn't hold
+    /**
+     * @dev Subtracts two unsigned integers, reverts on overflow (i.e. if subtrahend is greater than minuend).
+     */
+    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
+        require(b <= a);
+        uint256 c = a - b;
 
-    return c;
-  }
+        return c;
+    }
 
-  /**
-  * @dev Subtracts two numbers, reverts on overflow (i.e. if subtrahend is greater than minuend).
-  */
-  function sub(uint256 a, uint256 b) internal pure returns (uint256) {
-    require(b <= a);
-    uint256 c = a - b;
+    /**
+     * @dev Adds two unsigned integers, reverts on overflow.
+     */
+    function add(uint256 a, uint256 b) internal pure returns (uint256) {
+        uint256 c = a + b;
+        require(c >= a);
 
-    return c;
-  }
+        return c;
+    }
 
-  /**
-  * @dev Adds two numbers, reverts on overflow.
-  */
-  function add(uint256 a, uint256 b) internal pure returns (uint256) {
-    uint256 c = a + b;
-    require(c >= a);
-
-    return c;
-  }
-
-  /**
-  * @dev Divides two numbers and returns the remainder (unsigned integer modulo),
-  * reverts when dividing by zero.
-  */
-  function mod(uint256 a, uint256 b) internal pure returns (uint256) {
-    require(b != 0);
-    return a % b;
-  }
+    /**
+     * @dev Divides two unsigned integers and returns the remainder (unsigned integer modulo),
+     * reverts when dividing by zero.
+     */
+    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
+        require(b != 0);
+        return a % b;
+    }
 }

contracts/mocks/Acknowledger.sol

@@ -0,0 +1,19 @@
+pragma solidity ^0.5.2;
+
+contract Acknowledger {
+    event AcknowledgeFoo(uint256 a);
+    event AcknowledgeBarSingle(uint256 a);
+    event AcknowledgeBarDouble(uint256 a, uint256 b);
+
+    function foo(uint256 a) public {
+        emit AcknowledgeFoo(a);
+    }
+
+    function bar(uint256 a) public {
+        emit AcknowledgeBarSingle(a);
+    }
+
+    function bar(uint256 a, uint256 b) public {
+        emit AcknowledgeBarDouble(a, b);
+    }
+}

contracts/mocks/AddressImpl.sol

@@ -1,14 +1,9 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
 import "../utils/Address.sol";
 
 contract AddressImpl {
-  function isContract(address account)
-    external
-    view
-    returns (bool)
-  {
-    return Address.isContract(account); 
-  }
-  
+    function isContract(address account) external view returns (bool) {
+        return Address.isContract(account);
+    }
 }

contracts/mocks/AllowanceCrowdsaleImpl.sol

@@ -1,20 +1,13 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
 import "../token/ERC20/IERC20.sol";
 import "../crowdsale/emission/AllowanceCrowdsale.sol";
 
 contract AllowanceCrowdsaleImpl is AllowanceCrowdsale {
-
-  constructor (
-    uint256 rate,
-    address wallet,
-    IERC20 token,
-    address tokenWallet
-  )
-    public
-    Crowdsale(rate, wallet, token)
-    AllowanceCrowdsale(tokenWallet)
-  {
-  }
-
+    constructor (uint256 rate, address payable wallet, IERC20 token, address tokenWallet)
+        public
+    {
+        Crowdsale.initialize(rate, wallet, token);
+        AllowanceCrowdsale.initialize(tokenWallet);
+    }
 }

contracts/mocks/ArraysImpl.sol

@@ -1,18 +1,17 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
 import "../utils/Arrays.sol";
 
 contract ArraysImpl {
+    using Arrays for uint256[];
 
-  using Arrays for uint256[];
+    uint256[] private array;
 
-  uint256[] private array;
+    constructor (uint256[] memory _array) public {
+        array = _array;
+    }
 
-  constructor(uint256[] _array) public {
-    array = _array;
-  }
-
-  function findUpperBound(uint256 _element) external view returns (uint256) {
-    return array.findUpperBound(_element);
-  }
+    function findUpperBound(uint256 _element) external view returns (uint256) {
+        return array.findUpperBound(_element);
+    }
 }

contracts/mocks/CappedCrowdsaleImpl.sol

@@ -1,20 +1,13 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
 import "../token/ERC20/IERC20.sol";
 import "../crowdsale/validation/CappedCrowdsale.sol";
 
 contract CappedCrowdsaleImpl is CappedCrowdsale {
-
-  constructor (
-    uint256 rate,
-    address wallet,
-    IERC20 token,
-    uint256 cap
-  )
-    public
-    Crowdsale(rate, wallet, token)
-    CappedCrowdsale(cap)
-  {
-  }
-
+    constructor (uint256 rate, address payable wallet, IERC20 token, uint256 cap)
+        public
+    {
+        Crowdsale.initialize(rate, wallet, token);
+        CappedCrowdsale.initialize(cap);
+    }
 }

contracts/mocks/CapperRoleMock.sol

@@ -1,17 +1,22 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
 import "../access/roles/CapperRole.sol";
 
 contract CapperRoleMock is CapperRole {
-  function removeCapper(address account) public {
-    _removeCapper(account);
-  }
+    constructor() public {
+        CapperRole.initialize(msg.sender);
+    }
 
-  function onlyCapperMock() public view onlyCapper {
-  }
+    function removeCapper(address account) public {
+        _removeCapper(account);
+    }
 
-  // Causes a compilation error if super._removeCapper is not internal
-  function _removeCapper(address account) internal {
-    super._removeCapper(account);
-  }
+    function onlyCapperMock() public view onlyCapper {
+        // solhint-disable-previous-line no-empty-blocks
+    }
+
+    // Causes a compilation error if super._removeCapper is not internal
+    function _removeCapper(address account) internal {
+        super._removeCapper(account);
+    }
 }

contracts/mocks/ConditionalEscrowMock.sol

@@ -1,16 +1,20 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
 import "../payment/escrow/ConditionalEscrow.sol";
 
 // mock class using ConditionalEscrow
 contract ConditionalEscrowMock is ConditionalEscrow {
-  mapping(address => bool) private _allowed;
+    mapping(address => bool) private _allowed;
 
-  function setAllowed(address payee, bool allowed) public {
-    _allowed[payee] = allowed;
-  }
+    constructor() public {
+        ConditionalEscrow.initialize(msg.sender);
+    }
 
-  function withdrawalAllowed(address payee) public view returns (bool) {
-    return _allowed[payee];
-  }
+    function setAllowed(address payee, bool allowed) public {
+        _allowed[payee] = allowed;
+    }
+
+    function withdrawalAllowed(address payee) public view returns (bool) {
+        return _allowed[payee];
+    }
 }

contracts/mocks/CounterImpl.sol

@@ -1,20 +0,0 @@
-pragma solidity ^0.4.24;
-
-import "../drafts/Counter.sol";
-
-contract CounterImpl {
-  using Counter for Counter.Counter;
-
-  uint256 public theId;
-
-  // use whatever key you want to track your counters
-  mapping(string => Counter.Counter) private _counters;
-
-  function doThing(string key)
-    public
-    returns (uint256)
-  {
-    theId = _counters[key].next();
-    return theId;
-  }
-}

contracts/mocks/CountersImpl.sol

@@ -0,0 +1,21 @@
+pragma solidity ^0.5.2;
+
+import "../drafts/Counters.sol";
+
+contract CountersImpl {
+    using Counters for Counters.Counter;
+
+    Counters.Counter private _counter;
+
+    function current() public view returns (uint256) {
+        return _counter.current();
+    }
+
+    function increment() public {
+        _counter.increment();
+    }
+
+    function decrement() public {
+        _counter.decrement();
+    }
+}

contracts/mocks/CrowdsaleMock.sol

@@ -1,9 +1,9 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
 import "../crowdsale/Crowdsale.sol";
 
 contract CrowdsaleMock is Crowdsale {
-  constructor(uint256 rate, address wallet, IERC20 token) public
-    Crowdsale(rate, wallet, token) {
-  }
+    constructor (uint256 rate, address payable wallet, IERC20 token) public {
+        Crowdsale.initialize(rate, wallet, token);
+    }
 }

contracts/mocks/DetailedERC20Mock.sol

@@ -1,15 +0,0 @@
-pragma solidity ^0.4.24;
-
-import "../token/ERC20/ERC20.sol";
-import "../token/ERC20/ERC20Detailed.sol";
-
-contract ERC20DetailedMock is ERC20, ERC20Detailed {
-  constructor(
-    string name,
-    string symbol,
-    uint8 decimals
-  )
-    ERC20Detailed(name, symbol, decimals)
-    public
-  {}
-}

contracts/mocks/ECDSAMock.sol

@@ -1,23 +1,15 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
 import "../cryptography/ECDSA.sol";
 
 contract ECDSAMock {
-  using ECDSA for bytes32;
+    using ECDSA for bytes32;
 
-  function recover(bytes32 hash, bytes signature)
-    public
-    pure
-    returns (address)
-  {
-    return hash.recover(signature);
-  }
+    function recover(bytes32 hash, bytes memory signature) public pure returns (address) {
+        return hash.recover(signature);
+    }
 
-  function toEthSignedMessageHash(bytes32 hash)
-    public
-    pure
-    returns (bytes32)
-  {
-    return hash.toEthSignedMessageHash();
-  }
+    function toEthSignedMessageHash(bytes32 hash) public pure returns (bytes32) {
+        return hash.toEthSignedMessageHash();
+    }
 }

contracts/mocks/ERC165/ERC165InterfacesSupported.sol

@@ -1,66 +1,57 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
 import "../../introspection/IERC165.sol";
 
 /**
- * https://github.com/ethereum/EIPs/blob/master/EIPS/eip-214.md#specification
- * > Any attempts to make state-changing operations inside an execution instance with STATIC set to true will instead throw an exception.
+ * https://eips.ethereum.org/EIPS/eip-214#specification
+ * From the specification:
+ * > Any attempts to make state-changing operations inside an execution instance with STATIC set to true will instead
+ * throw an exception.
  * > These operations include [...], LOG0, LOG1, LOG2, [...]
  *
  * therefore, because this contract is staticcall'd we need to not emit events (which is how solidity-coverage works)
  * solidity-coverage ignores the /mocks folder, so we duplicate its implementation here to avoid instrumenting it
  */
 contract SupportsInterfaceWithLookupMock is IERC165 {
+    bytes4 public constant INTERFACE_ID_ERC165 = 0x01ffc9a7;
+    /*
+     * 0x01ffc9a7 ===
+     *     bytes4(keccak256('supportsInterface(bytes4)'))
+     */
 
-  bytes4 public constant InterfaceId_ERC165 = 0x01ffc9a7;
-  /**
-   * 0x01ffc9a7 ===
-   *   bytes4(keccak256('supportsInterface(bytes4)'))
-   */
+    /**
+     * @dev a mapping of interface id to whether or not it's supported
+     */
+    mapping(bytes4 => bool) private _supportedInterfaces;
 
-  /**
-   * @dev a mapping of interface id to whether or not it's supported
-   */
-  mapping(bytes4 => bool) private _supportedInterfaces;
+    /**
+     * @dev A contract implementing SupportsInterfaceWithLookup
+     * implement ERC165 itself
+     */
+    constructor () public {
+        _registerInterface(INTERFACE_ID_ERC165);
+    }
 
-  /**
-   * @dev A contract implementing SupportsInterfaceWithLookup
-   * implement ERC165 itself
-   */
-  constructor()
-    public
-  {
-    _registerInterface(InterfaceId_ERC165);
-  }
+    /**
+     * @dev implement supportsInterface(bytes4) using a lookup table
+     */
+    function supportsInterface(bytes4 interfaceId) external view returns (bool) {
+        return _supportedInterfaces[interfaceId];
+    }
 
-  /**
-   * @dev implement supportsInterface(bytes4) using a lookup table
-   */
-  function supportsInterface(bytes4 interfaceId)
-    external
-    view
-    returns (bool)
-  {
-    return _supportedInterfaces[interfaceId];
-  }
-
-  /**
-   * @dev private method for registering an interface
-   */
-  function _registerInterface(bytes4 interfaceId)
-    internal
-  {
-    require(interfaceId != 0xffffffff);
-    _supportedInterfaces[interfaceId] = true;
-  }
+    /**
+     * @dev private method for registering an interface
+     */
+    function _registerInterface(bytes4 interfaceId) internal {
+        require(interfaceId != 0xffffffff);
+        _supportedInterfaces[interfaceId] = true;
+    }
 }
 
 contract ERC165InterfacesSupported is SupportsInterfaceWithLookupMock {
-  constructor (bytes4[] interfaceIds)
-    public
-  {
-    for (uint256 i = 0; i < interfaceIds.length; i++) {
-      _registerInterface(interfaceIds[i]);
+    constructor (bytes4[] memory interfaceIds) public {
+        for (uint256 i = 0; i < interfaceIds.length; i++) {
+            _registerInterface(interfaceIds[i]);
+        }
     }
-  }
 }

contracts/mocks/ERC165/ERC165NotSupported.sol

@@ -1,5 +1,5 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
 contract ERC165NotSupported {
-
+    // solhint-disable-previous-line no-empty-blocks
 }

contracts/mocks/ERC165CheckerMock.sol

@@ -1,31 +1,19 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
 import "../introspection/ERC165Checker.sol";
 
 contract ERC165CheckerMock {
-  using ERC165Checker for address;
+    using ERC165Checker for address;
 
-  function supportsERC165(address account)
-    public
-    view
-    returns (bool)
-  {
-    return account._supportsERC165();
-  }
+    function supportsERC165(address account) public view returns (bool) {
+        return account._supportsERC165();
+    }
 
-  function supportsInterface(address account, bytes4 interfaceId)
-    public
-    view
-    returns (bool)
-  {
-    return account._supportsInterface(interfaceId);
-  }
+    function supportsInterface(address account, bytes4 interfaceId) public view returns (bool) {
+        return account._supportsInterface(interfaceId);
+    }
 
-  function supportsAllInterfaces(address account, bytes4[] interfaceIds)
-    public
-    view
-    returns (bool)
-  {
-    return account._supportsAllInterfaces(interfaceIds);
-  }
+    function supportsAllInterfaces(address account, bytes4[] memory interfaceIds) public view returns (bool) {
+        return account._supportsAllInterfaces(interfaceIds);
+    }
 }

contracts/mocks/ERC165Mock.sol

@@ -1,11 +1,13 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
 import "../introspection/ERC165.sol";
 
 contract ERC165Mock is ERC165 {
-  function registerInterface(bytes4 interfaceId)
-    public
-  {
-    _registerInterface(interfaceId);
-  }
+    constructor() public {
+        ERC165.initialize();
+    }
+
+    function registerInterface(bytes4 interfaceId) public {
+        _registerInterface(interfaceId);
+    }
 }

contracts/mocks/ERC20BurnableMock.sol

@@ -1,11 +1,9 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
 import "../token/ERC20/ERC20Burnable.sol";
 
 contract ERC20BurnableMock is ERC20Burnable {
-
-  constructor(address initialAccount, uint256 initialBalance) public {
-    _mint(initialAccount, initialBalance);
-  }
-
+    constructor(address initialAccount, uint256 initialBalance) public {
+        _mint(initialAccount, initialBalance);
+    }
 }

contracts/mocks/ERC20CappedMock.sol

@@ -0,0 +1,13 @@
+pragma solidity ^0.5.0;
+
+import "../token/ERC20/ERC20Capped.sol";
+import "./MinterRoleMock.sol";
+
+
+contract ERC20CappedMock is ERC20Capped, MinterRoleMock {
+
+    constructor(uint256 cap) public {
+        ERC20Capped.initialize(cap, msg.sender);
+    }
+
+}

contracts/mocks/ERC20DetailedMock.sol

@@ -0,0 +1,12 @@
+pragma solidity ^0.5.2;
+
+import "../token/ERC20/ERC20.sol";
+import "../token/ERC20/ERC20Detailed.sol";
+
+contract ERC20DetailedMock is ERC20, ERC20Detailed {
+    constructor (string memory name, string memory symbol, uint8 decimals)
+        public
+    {
+        ERC20Detailed.initialize(name, symbol, decimals);
+    }
+}

contracts/mocks/ERC20MetadataMock.sol

@@ -0,0 +1,14 @@
+pragma solidity ^0.5.0;
+
+import "../token/ERC20/ERC20.sol";
+import "../drafts/ERC1046/ERC20Metadata.sol";
+
+contract ERC20MetadataMock is ERC20, ERC20Metadata {
+    constructor (string memory tokenURI) public {
+        ERC20Metadata.initialize(tokenURI);
+    }
+
+    function setTokenURI(string memory tokenURI) public {
+        _setTokenURI(tokenURI);
+    }
+}

contracts/mocks/ERC20MigratorMock.sol

@@ -0,0 +1,12 @@
+pragma solidity ^0.5.0;
+
+import "../drafts/ERC20Migrator.sol";
+
+
+contract ERC20MigratorMock is ERC20Migrator {
+
+    constructor(IERC20 legacyToken) public {
+        ERC20Migrator.initialize(legacyToken);
+    }
+
+}

contracts/mocks/ERC20MintableMock.sol

@@ -1,7 +1,10 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
 import "../token/ERC20/ERC20Mintable.sol";
 import "./MinterRoleMock.sol";
 
 contract ERC20MintableMock is ERC20Mintable, MinterRoleMock {
+    constructor() public {
+        ERC20Mintable.initialize(msg.sender);
+    }
 }

contracts/mocks/ERC20Mock.sol

@@ -1,24 +1,26 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
 import "../token/ERC20/ERC20.sol";
 
 // mock class using ERC20
 contract ERC20Mock is ERC20 {
+    constructor (address initialAccount, uint256 initialBalance) public {
+        _mint(initialAccount, initialBalance);
+    }
 
-  constructor(address initialAccount, uint256 initialBalance) public {
-    _mint(initialAccount, initialBalance);
-  }
+    function mint(address account, uint256 amount) public {
+        _mint(account, amount);
+    }
 
-  function mint(address account, uint256 amount) public {
-    _mint(account, amount);
-  }
+    function burn(address account, uint256 amount) public {
+        _burn(account, amount);
+    }
 
-  function burn(address account, uint256 amount) public {
-    _burn(account, amount);
-  }
-
-  function burnFrom(address account, uint256 amount) public {
-    _burnFrom(account, amount);
-  }
+    function burnFrom(address account, uint256 amount) public {
+        _burnFrom(account, amount);
+    }
 
+    function approveInternal(address owner, address spender, uint256 value) public {
+        _approve(owner, spender, value);
+    }
 }

contracts/mocks/ERC20PausableMock.sol

@@ -1,13 +1,12 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
 import "../token/ERC20/ERC20Pausable.sol";
 import "./PauserRoleMock.sol";
 
 // mock class using ERC20Pausable
 contract ERC20PausableMock is ERC20Pausable, PauserRoleMock {
-
-  constructor(address initialAccount, uint initialBalance) public {
-    _mint(initialAccount, initialBalance);
-  }
-
+    constructor (address initialAccount, uint initialBalance) public {
+        ERC20Pausable.initialize(msg.sender);
+        _mint(initialAccount, initialBalance);
+    }
 }

contracts/mocks/ERC20SnapshotMock.sol

@@ -0,0 +1,18 @@
+pragma solidity ^0.5.2;
+
+import "../drafts/ERC20Snapshot.sol";
+
+
+contract ERC20SnapshotMock is ERC20Snapshot {
+    constructor(address initialAccount, uint256 initialBalance) public {
+        _mint(initialAccount, initialBalance);
+    }
+
+    function mint(address account, uint256 amount) public {
+        _mint(account, amount);
+    }
+
+    function burn(address account, uint256 amount) public {
+        _burn(account, amount);
+    }
+}

contracts/mocks/ERC20WithMetadataMock.sol

@@ -1,11 +0,0 @@
-pragma solidity ^0.4.24;
-
-import "../token/ERC20/ERC20.sol";
-import "../drafts/ERC1046/TokenMetadata.sol";
-
-contract ERC20WithMetadataMock is ERC20, ERC20WithMetadata {
-  constructor(string tokenURI) public
-    ERC20WithMetadata(tokenURI)
-  {
-  }
-}

contracts/mocks/ERC721FullMock.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
 import "../token/ERC721/ERC721Full.sol";
 import "../token/ERC721/ERC721Mintable.sol";
@@ -7,26 +7,27 @@ import "../token/ERC721/ERC721Burnable.sol";
 
 /**
  * @title ERC721FullMock
- * This mock just provides a public mint and burn functions for testing purposes,
- * and a public setter for metadata URI
+ * This mock just provides public functions for setting metadata URI, getting all tokens of an owner,
+ * checking token existence, removal of a token from an address
  */
-contract ERC721FullMock
-  is ERC721Full, ERC721Mintable, ERC721MetadataMintable, ERC721Burnable {
+contract ERC721FullMock is ERC721Full, ERC721Mintable, ERC721MetadataMintable, ERC721Burnable {
+    constructor (string memory name, string memory symbol) public {
+        ERC721.initialize();
+        ERC721Metadata.initialize(name, symbol);
+        ERC721Enumerable.initialize();
+        ERC721Mintable.initialize(msg.sender);
+        ERC721MetadataMintable.initialize(msg.sender);
+    }
 
-  constructor(string name, string symbol) public
-    ERC721Mintable()
-    ERC721Full(name, symbol)
-  {}
+    function exists(uint256 tokenId) public view returns (bool) {
+        return _exists(tokenId);
+    }
 
-  function exists(uint256 tokenId) public view returns (bool) {
-    return _exists(tokenId);
-  }
+    function tokensOfOwner(address owner) public view returns (uint256[] memory) {
+        return _tokensOfOwner(owner);
+    }
 
-  function setTokenURI(uint256 tokenId, string uri) public {
-    _setTokenURI(tokenId, uri);
-  }
-
-  function removeTokenFrom(address from, uint256 tokenId) public {
-    _removeTokenFrom(from, tokenId);
-  }
+    function setTokenURI(uint256 tokenId, string memory uri) public {
+        _setTokenURI(tokenId, uri);
+    }
 }

contracts/mocks/ERC721MintableBurnableImpl.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
 import "../token/ERC721/ERC721Full.sol";
 import "../token/ERC721/ERC721Mintable.sol";
@@ -8,13 +8,12 @@ import "../token/ERC721/ERC721Burnable.sol";
 /**
  * @title ERC721MintableBurnableImpl
  */
-contract ERC721MintableBurnableImpl
-  is ERC721Full, ERC721Mintable, ERC721MetadataMintable, ERC721Burnable {
-
-  constructor()
-    ERC721Mintable()
-    ERC721Full("Test", "TEST")
-    public
-  {
-  }
+contract ERC721MintableBurnableImpl is ERC721Full, ERC721Mintable, ERC721MetadataMintable, ERC721Burnable {
+    constructor () public {
+        ERC721.initialize();
+        ERC721Metadata.initialize("Test", "TEST");
+        ERC721Enumerable.initialize();
+        ERC721Mintable.initialize(msg.sender);
+        ERC721MetadataMintable.initialize(msg.sender);
+    }
 }

contracts/mocks/ERC721Mock.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
 import "../token/ERC721/ERC721.sol";
 
@@ -7,11 +7,19 @@ import "../token/ERC721/ERC721.sol";
  * This mock just provides a public mint and burn functions for testing purposes
  */
 contract ERC721Mock is ERC721 {
-  function mint(address to, uint256 tokenId) public {
-    _mint(to, tokenId);
-  }
+    constructor() public {
+        ERC721.initialize();
+    }
 
-  function burn(uint256 tokenId) public {
-    _burn(ownerOf(tokenId), tokenId);
-  }
+    function mint(address to, uint256 tokenId) public {
+        _mint(to, tokenId);
+    }
+
+    function burn(address owner, uint256 tokenId) public {
+        _burn(owner, tokenId);
+    }
+
+    function burn(uint256 tokenId) public {
+        _burn(tokenId);
+    }
 }

contracts/mocks/ERC721PausableMock.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
 import "../token/ERC721/ERC721Pausable.sol";
 import "./PauserRoleMock.sol";
@@ -8,15 +8,20 @@ import "./PauserRoleMock.sol";
  * This mock just provides a public mint, burn and exists functions for testing purposes
  */
 contract ERC721PausableMock is ERC721Pausable, PauserRoleMock {
-  function mint(address to, uint256 tokenId) public {
-    super._mint(to, tokenId);
-  }
+    constructor() public {
+        ERC721.initialize();
+        ERC721Pausable.initialize(msg.sender);
+    }
 
-  function burn(uint256 tokenId) public {
-    super._burn(ownerOf(tokenId), tokenId);
-  }
+    function mint(address to, uint256 tokenId) public {
+        super._mint(to, tokenId);
+    }
 
-  function exists(uint256 tokenId) public view returns (bool) {
-    return super._exists(tokenId);
-  }
+    function burn(uint256 tokenId) public {
+        super._burn(tokenId);
+    }
+
+    function exists(uint256 tokenId) public view returns (bool) {
+        return super._exists(tokenId);
+    }
 }

contracts/mocks/ERC721ReceiverMock.sol

@@ -1,41 +1,23 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
 import "../token/ERC721/IERC721Receiver.sol";
 
 contract ERC721ReceiverMock is IERC721Receiver {
-  bytes4 private _retval;
-  bool private _reverts;
+    bytes4 private _retval;
+    bool private _reverts;
 
-  event Received(
-    address operator,
-    address from,
-    uint256 tokenId,
-    bytes data,
-    uint256 gas
-  );
+    event Received(address operator, address from, uint256 tokenId, bytes data, uint256 gas);
 
-  constructor(bytes4 retval, bool reverts) public {
-    _retval = retval;
-    _reverts = reverts;
-  }
+    constructor (bytes4 retval, bool reverts) public {
+        _retval = retval;
+        _reverts = reverts;
+    }
 
-  function onERC721Received(
-    address operator,
-    address from,
-    uint256 tokenId,
-    bytes data
-  )
-    public
-    returns(bytes4)
-  {
-    require(!_reverts);
-    emit Received(
-      operator,
-      from,
-      tokenId,
-      data,
-      gasleft() // msg.gas was deprecated in solidityv0.4.21
-    );
-    return _retval;
-  }
+    function onERC721Received(address operator, address from, uint256 tokenId, bytes memory data)
+        public returns (bytes4)
+    {
+        require(!_reverts);
+        emit Received(operator, from, tokenId, data, gasleft());
+        return _retval;
+    }
 }

contracts/mocks/EscrowMock.sol

@@ -0,0 +1,9 @@
+pragma solidity ^0.5.0;
+
+import "../payment/escrow/Escrow.sol";
+
+contract EscrowMock is Escrow {
+    constructor() public {
+        Escrow.initialize(msg.sender);
+    }
+}

contracts/mocks/EventEmitter.sol

@@ -1,62 +1,73 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
 contract EventEmitter {
-  event Argumentless();
-  event ShortUint(uint8 value);
-  event ShortInt(int8 value);
-  event LongUint(uint256 value);
-  event LongInt(int256 value);
-  event Address(address value);
-  event Boolean(bool value);
-  event String(string value);
-  event LongUintBooleanString(
-    uint256 uintValue,
-    bool booleanValue,
-    string stringValue
-  );
+    event Argumentless();
+    event ShortUint(uint8 value);
+    event ShortInt(int8 value);
+    event LongUint(uint256 value);
+    event LongInt(int256 value);
+    event Address(address value);
+    event Boolean(bool value);
+    event String(string value);
+    event LongUintBooleanString(uint256 uintValue, bool booleanValue, string stringValue);
 
-  function emitArgumentless() public {
-    emit Argumentless();
-  }
+    constructor (uint8 uintValue, bool booleanValue, string memory stringValue) public {
+        emit ShortUint(uintValue);
+        emit Boolean(booleanValue);
+        emit String(stringValue);
+    }
 
-  function emitShortUint(uint8 value) public {
-    emit ShortUint(value);
-  }
+    function emitArgumentless() public {
+        emit Argumentless();
+    }
 
-  function emitShortInt(int8 value) public {
-    emit ShortInt(value);
-  }
+    function emitShortUint(uint8 value) public {
+        emit ShortUint(value);
+    }
 
-  function emitLongUint(uint256 value) public {
-    emit LongUint(value);
-  }
+    function emitShortInt(int8 value) public {
+        emit ShortInt(value);
+    }
 
-  function emitLongInt(int256 value) public {
-    emit LongInt(value);
-  }
+    function emitLongUint(uint256 value) public {
+        emit LongUint(value);
+    }
 
-  function emitAddress(address value) public {
-    emit Address(value);
-  }
+    function emitLongInt(int256 value) public {
+        emit LongInt(value);
+    }
 
-  function emitBoolean(bool value) public {
-    emit Boolean(value);
-  }
+    function emitAddress(address value) public {
+        emit Address(value);
+    }
 
-  function emitString(string value) public {
-    emit String(value);
-  }
+    function emitBoolean(bool value) public {
+        emit Boolean(value);
+    }
 
-  function emitLongUintBooleanString(
-    uint256 uintValue,
-    bool booleanValue,
-    string stringValue)
-  public {
-    emit LongUintBooleanString(uintValue, booleanValue, stringValue);
-  }
+    function emitString(string memory value) public {
+        emit String(value);
+    }
 
-  function emitLongUintAndBoolean(uint256 uintValue, bool boolValue) public {
-    emit LongUint(uintValue);
-    emit Boolean(boolValue);
-  }
+    function emitLongUintBooleanString(uint256 uintValue, bool booleanValue, string memory stringValue) public {
+        emit LongUintBooleanString(uintValue, booleanValue, stringValue);
+    }
+
+    function emitLongUintAndBoolean(uint256 uintValue, bool boolValue) public {
+        emit LongUint(uintValue);
+        emit Boolean(boolValue);
+    }
+
+    function emitStringAndEmitIndirectly(string memory value, IndirectEventEmitter emitter) public {
+        emit String(value);
+        emitter.emitStringIndirectly(value);
+    }
+}
+
+contract IndirectEventEmitter {
+    event IndirectString(string value);
+
+    function emitStringIndirectly(string memory value) public {
+        emit IndirectString(value);
+    }
 }

contracts/mocks/Failer.sol

@@ -0,0 +1,23 @@
+pragma solidity ^0.5.2;
+
+contract Failer {
+    uint256[] private array;
+
+    function dontFail() public pure {
+        // solhint-disable-previous-line no-empty-blocks
+    }
+
+    function failWithRevert() public pure {
+        revert();
+    }
+
+    function failWithThrow() public pure {
+        assert(false);
+    }
+
+    function failWithOutOfGas() public {
+        for (uint256 i = 0; i < 2**200; ++i) {
+            array.push(i);
+        }
+    }
+}

contracts/mocks/FinalizableCrowdsaleImpl.sol

@@ -1,21 +1,13 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
 import "../token/ERC20/IERC20.sol";
 import "../crowdsale/distribution/FinalizableCrowdsale.sol";
 
 contract FinalizableCrowdsaleImpl is FinalizableCrowdsale {
-
-  constructor (
-    uint256 openingTime,
-    uint256 closingTime,
-    uint256 rate,
-    address wallet,
-    IERC20 token
-  )
-    public
-    Crowdsale(rate, wallet, token)
-    TimedCrowdsale(openingTime, closingTime)
-  {
-  }
-
+    constructor (uint256 openingTime, uint256 closingTime, uint256 rate, address payable wallet, IERC20 token)
+        public
+    {
+        Crowdsale.initialize(rate, wallet, token);
+        TimedCrowdsale.initialize(openingTime, closingTime);
+    }
 }

contracts/mocks/ForceEther.sol

@@ -0,0 +1,18 @@
+pragma solidity ^0.5.0;
+
+
+// @title Force Ether into a contract.
+// @notice  even
+// if the contract is not payable.
+// @notice To use, construct the contract with the target as argument.
+// @author Remco Bloemen <remco@neufund.org>
+contract ForceEther {
+
+    constructor() public payable {
+        // solhint-disable-previous-line no-empty-blocks
+    }
+
+    function destroyAndSend(address payable recipient) public {
+        selfdestruct(recipient);
+    }
+}

contracts/mocks/IncreasingPriceCrowdsaleImpl.sol

@@ -1,23 +1,21 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
 import "../crowdsale/price/IncreasingPriceCrowdsale.sol";
 import "../math/SafeMath.sol";
 
 contract IncreasingPriceCrowdsaleImpl is IncreasingPriceCrowdsale {
-
-  constructor (
-    uint256 openingTime,
-    uint256 closingTime,
-    address wallet,
-    IERC20 token,
-    uint256 initialRate,
-    uint256 finalRate
-  )
-    public
-    Crowdsale(initialRate, wallet, token)
-    TimedCrowdsale(openingTime, closingTime)
-    IncreasingPriceCrowdsale(initialRate, finalRate)
-  {
-  }
-
+    constructor (
+        uint256 openingTime,
+        uint256 closingTime,
+        address payable wallet,
+        IERC20 token,
+        uint256 initialRate,
+        uint256 finalRate
+    )
+        public
+    {
+        Crowdsale.initialize(initialRate, wallet, token);
+        TimedCrowdsale.initialize(openingTime, closingTime);
+        IncreasingPriceCrowdsale.initialize(initialRate, finalRate);
+    }
 }

contracts/mocks/IndividuallyCappedCrowdsaleImpl.sol

@@ -1,19 +1,12 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
 import "../token/ERC20/IERC20.sol";
 import "../crowdsale/validation/IndividuallyCappedCrowdsale.sol";
 import "./CapperRoleMock.sol";
 
-contract IndividuallyCappedCrowdsaleImpl
-  is IndividuallyCappedCrowdsale, CapperRoleMock {
-
-  constructor(
-    uint256 rate,
-    address wallet,
-    IERC20 token
-  )
-    public
-    Crowdsale(rate, wallet, token)
-  {
-  }
+contract IndividuallyCappedCrowdsaleImpl is IndividuallyCappedCrowdsale, CapperRoleMock {
+    constructor (uint256 rate, address payable wallet, IERC20 token) public {
+        Crowdsale.initialize(rate, wallet, token);
+        IndividuallyCappedCrowdsale.initialize(msg.sender);
+    }
 }

contracts/mocks/MathMock.sol

@@ -1,17 +1,17 @@
-pragma solidity ^0.4.24;
+pragma solidity ^0.5.2;
 
 import "../math/Math.sol";
 
 contract MathMock {
-  function max(uint256 a, uint256 b) public pure returns (uint256) {
-    return Math.max(a, b);
-  }
+    function max(uint256 a, uint256 b) public pure returns (uint256) {
+        return Math.max(a, b);
+    }
 
-  function min(uint256 a, uint256 b) public pure returns (uint256) {
-    return Math.min(a, b);
-  }
+    function min(uint256 a, uint256 b) public pure returns (uint256) {
+        return Math.min(a, b);
+    }
 
-  function average(uint256 a, uint256 b) public pure returns (uint256) {
-    return Math.average(a, b);
-  }
+    function average(uint256 a, uint256 b) public pure returns (uint256) {
+        return Math.average(a, b);
+    }
 }