Release v1.12.0

* Changed Crowdsale inheritance order.

* Changed FinalizableCrowdsale inheritance order.

(cherry picked from commit 3d86c58d2c)

.editorconfig

@@ -0,0 +1,12 @@
+# EditorConfig is awesome: https://EditorConfig.org
+
+# top-most EditorConfig file
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+indent_size = 2
+indent_style = space
+insert_final_newline = true
+trim_trailing_whitespace = true

.eslintrc

@@ -21,31 +21,34 @@
   "rules": {
 
     // Strict mode
-    "strict": [2, "global"],
+    "strict": ["error", "global"],
 
     // Code style
-    "indent": [2, 2],
-    "quotes": [2, "single"],
+    "camelcase": ["error", {"properties": "always"}],
+    "comma-dangle": ["warn", "always-multiline"],
+    "comma-spacing": ["error", {"before": false, "after": true}],
+    "dot-notation": ["error", {"allowKeywords": true, "allowPattern": ""}],
+    "eol-last": ["error", "always"],
+    "eqeqeq": ["error", "smart"],
+    "generator-star-spacing": ["error", "before"],
+    "indent": ["error", 2],
+    "max-len": ["error", 120, 2],
+    "no-debugger": "off",
+    "no-dupe-args": "error",
+    "no-dupe-keys": "error",
+    "no-mixed-spaces-and-tabs": ["error", "smart-tabs"],
+    "no-redeclare": ["error", {"builtinGlobals": true}],
+    "no-trailing-spaces": ["error", { "skipBlankLines": false }],
+    "no-undef": "error",
+    "no-use-before-define": "off",
+    "no-var": "error",
+    "object-curly-spacing": ["error", "always"],
+    "prefer-const": "error",
+    "quotes": ["error", "single"],
     "semi": ["error", "always"],
     "space-before-function-paren": ["error", "always"],
-    "no-use-before-define": 0,
-    "eqeqeq": [2, "smart"],
-    "dot-notation": [2, {"allowKeywords": true, "allowPattern": ""}],
-    "no-redeclare": [2, {"builtinGlobals": true}],
-    "no-trailing-spaces": [2, { "skipBlankLines": true }],
-    "eol-last": 1,
-    "comma-spacing": [2, {"before": false, "after": true}],
-    "camelcase": [2, {"properties": "always"}],
-    "no-mixed-spaces-and-tabs": [2, "smart-tabs"],
-    "comma-dangle": [1, "always-multiline"],
-    "no-dupe-args": 2,
-    "no-dupe-keys": 2,
-    "no-debugger": 0,
-    "no-undef": 2,
-    "object-curly-spacing": [2, "always"],
-    "max-len": [2, 120, 2],
-    "generator-star-spacing": ["error", "before"],
-    "promise/avoid-new": 0,
-    "promise/always-return": 0
+
+    "promise/always-return": "off",
+    "promise/avoid-new": "off",
   }
 }

.github/ISSUE_TEMPLATE.md

@@ -12,7 +12,7 @@
 Next, we need to know what your environment looks like.
 
 - Which version of OpenZeppelin are you using?
-- What network are you deploying to? testrpc? Ganache? Ropsten?
+- What network are you deploying to? Ganache? Ropsten?
 - How are you deploying your OpenZeppelin-backed contracts? truffle? Remix? Let us know!
 
 ## 📝 Details

.github/PULL_REQUEST_TEMPLATE.md

@@ -11,7 +11,7 @@ Fixes #
 
 <!-- 3. Before submitting, please review the following checklist: -->
 
-- [ ] 📘 I've reviewed the [OpenZeppelin Contributor Guidelines](/docs/CONTRIBUTING.md)
+- [ ] 📘 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:all:fix`).
+- [ ] 🎨 I've run the JS/Solidity linters and fixed any issues (`npm run lint:all:fix`).

.gitignore

@@ -34,3 +34,6 @@ build/
 
 # lol macs
 .DS_Store/
+
+# truffle
+.node-xmlhttprequest-*

.jshintrc

@@ -1,48 +0,0 @@
-{
-    "bitwise": false,     // Prohibit bitwise operators (&, |, ^, etc.).
-    "browser": true,      // Standard browser globals e.g. `window`, `document`.
-    "camelcase": false,   // Permit only camelcase for `var` and `object indexes`.
-    "curly": true,        // Require {} for every new block or scope.
-    "devel": false,       // Allow development statements e.g. `console.log();`.
-    "eqeqeq": true,       // Require triple equals i.e. `===`.
-    "esnext": true,       // Allow ES.next specific features such as `const` and `let`.
-    "freeze": true,       // Forbid overwriting prototypes of native objects such as Array, Date and so on.
-    "immed": true,        // Require immediate invocations to be wrapped in parens e.g. `( function(){}() );`
-    "indent": 2,          // Specify indentation spacing
-    "latedef": true,      // Prohibit variable use before definition.
-    "newcap": false,      // Require capitalization of all constructor functions e.g. `new F()`.
-    "noarg": true,        // Prohibit use of `arguments.caller` and `arguments.callee`.
-    "node": true,         // Enable globals available when code is running inside of the NodeJS runtime environment.
-    "noempty": true,      // Prohibit use of empty blocks.
-    "nonew": true,        // Prohibits the use of constructor functions for side-effects
-    "quotmark": "single", // Define quotes to string values.
-    "regexp": true,       // Prohibit `.` and `[^...]` in regular expressions.
-    "smarttabs": false,   // Supress warnings about mixed tabs and spaces
-    "strict": true,       // Require `use strict` pragma in every file.
-    "trailing": true,     // Prohibit trailing whitespaces.
-    "undef": true,        // Require all non-global variables be declared before they are used.
-    "unused": true,       // Warn unused variables.
-
-    "maxparams": 4,       // Maximum number of parameters for a function
-    "maxstatements": 15,  // Maximum number of statements in a function
-    "maxcomplexity": 10,  // Cyclomatic complexity (http://en.wikipedia.org/wiki/Cyclomatic_complexity)
-    "maxdepth": 4,        // Maximum depth of nested control structures
-    "maxlen": 120,        // Maximum number of cols in a line
-    "multistr": true,     // Allow use of multiline EOL escaping
-    "experimental": ["asyncawait", "asyncreqawait"],
-
-    "predef": [ // Extra globals.
-        "after",
-        "afterEach",
-        "before",
-        "beforeEach",
-        "define",
-        "describe",
-        "exports",
-        "it",
-        "web3",
-        "artifacts",
-        "contract",
-        "assert"
-    ]
-}

.soliumrc.json

@@ -2,9 +2,14 @@
   "extends": "solium:all",
   "plugins": ["security"],
   "rules": {
-    "quotes": ["error", "double"],
+    "error-reason": "off",
     "indentation": ["error", 2],
-    "arg-overflow": ["warning", 3],
+    "max-len": ["warning", 79],
+    "no-constant": ["error"],
+    "no-empty-blocks": "off",
+    "quotes": ["error", "double"],
+    "uppercase": "off",
+
     "security/enforce-explicit-visibility": ["error"],
     "security/no-block-members": ["warning"],
     "security/no-inline-assembly": ["warning"]

.travis.yml

@@ -10,10 +10,12 @@ cache:
 env:
   -
   - SOLIDITY_COVERAGE=true
+  - SOLC_NIGHTLY=true
 matrix:
   fast_finish: true
   allow_failures:
     - env: SOLIDITY_COVERAGE=true
+    - env: SOLC_NIGHTLY=true
 before_script:
   - truffle version
 script:

CODE_OF_CONDUCT.md

@@ -0,0 +1,73 @@
+# Contributor Covenant Code of Conduct
+
+## Our Pledge
+
+In the interest of fostering an open and welcoming environment, we as
+contributors and maintainers pledge to making participation in our project and
+our community a harassment-free experience for everyone, regardless of age, body
+size, disability, ethnicity, sex characteristics, gender identity and expression,
+level of experience, education, socio-economic status, nationality, personal
+appearance, race, religion, or sexual identity and orientation.
+
+## Our Standards
+
+Examples of behavior that contributes to creating a positive environment
+include:
+
+* Using welcoming and inclusive language
+* Being respectful of differing viewpoints and experiences
+* Gracefully accepting constructive criticism
+* Focusing on what is best for the community
+* Showing empathy towards other community members
+
+Examples of unacceptable behavior by participants include:
+
+* The use of sexualized language or imagery and unwelcome sexual attention or
+  advances
+* Trolling, insulting/derogatory comments, and personal or political attacks
+* Public or private harassment
+* Publishing others' private information, such as a physical or electronic
+  address, without explicit permission
+* Other conduct which could reasonably be considered inappropriate in a
+  professional setting
+
+## Our Responsibilities
+
+Project maintainers are responsible for clarifying the standards of acceptable
+behavior and are expected to take appropriate and fair corrective action in
+response to any instances of unacceptable behavior.
+
+Project maintainers have the right and responsibility to remove, edit, or
+reject comments, commits, code, wiki edits, issues, and other contributions
+that are not aligned to this Code of Conduct, or to ban temporarily or
+permanently any contributor for other behaviors that they deem inappropriate,
+threatening, offensive, or harmful.
+
+## Scope
+
+This Code of Conduct applies both within project spaces and in public spaces
+when an individual is representing the project or its community. Examples of
+representing a project or community include using an official project e-mail
+address, posting via an official social media account, or acting as an appointed
+representative at an online or offline event. Representation of a project may be
+further defined and clarified by project maintainers.
+
+## Enforcement
+
+Instances of abusive, harassing, or otherwise unacceptable behavior may be
+reported by contacting the project team at maintainers@openzeppelin.org. All
+complaints will be reviewed and investigated and will result in a response that
+is deemed necessary and appropriate to the circumstances. The project team is
+obligated to maintain confidentiality with regard to the reporter of an incident.
+Further details of specific enforcement policies may be posted separately.
+
+Project maintainers who do not follow or enforce the Code of Conduct in good
+faith may face temporary or permanent repercussions as determined by other
+members of the project's leadership.
+
+## Attribution
+
+This Code of Conduct is adapted from the [Contributor Covenant][homepage], version 1.4,
+available at https://www.contributor-covenant.org/version/1/4/code-of-conduct.html
+
+[homepage]: https://www.contributor-covenant.org

CONTRIBUTING.md

@@ -5,29 +5,28 @@ We really appreciate and value contributions to OpenZeppelin. Please take 5' to
 
 ## Contribution guidelines
 
-Smart contracts manage value and are highly vulnerable to errors and attacks. We have very strict guidelines, please make sure to review them: ["Contribution guidelines wiki entry"](https://github.com/OpenZeppelin/zeppelin-solidity/wiki/Contribution-guidelines).
+Smart contracts manage value and are highly vulnerable to errors and attacks. We have very strict guidelines, please make sure to review them: ["Contribution guidelines wiki entry"](https://github.com/OpenZeppelin/openzeppelin-solidity/wiki/Contribution-guidelines).
 
 ## Creating Pull Requests (PRs)
 
 As a contributor, you are expected to fork this repository, work on your own fork and then submit pull requests. The pull requests will be reviewed and eventually merged into the main repo. See ["Fork-a-Repo"](https://help.github.com/articles/fork-a-repo/) for how this works.
 
 *IMPORTANT* 
-* Please use `rebase` instead of `merge` when updating your fork.
-* Please see ["Git flow wiki entry"](https://github.com/OpenZeppelin/zeppelin-solidity/wiki/Git-flow) for understanding how to use branches in this repository.
+* Please see ["Git flow wiki entry"](https://github.com/OpenZeppelin/openzeppelin-solidity/wiki/Git-flow) for understanding how to use branches in this repository.
 
 ## A typical workflow
 
 1) Make sure your fork is up to date with the main repository:
 
 ```
-cd zeppelin-solidity
+cd openzeppelin-solidity
+git remote add upstream https://github.com/OpenZeppelin/openzeppelin-solidity.git
 git fetch upstream
-git checkout development
-git pull --rebase upstream development
+git pull --rebase upstream master
 ```
-NOTE: The directory `zeppelin-solidity` represents your fork's local copy.
+NOTE: The directory `openzeppelin-solidity` represents your fork's local copy.
 
-2) Branch out from `development` into `fix/some-bug-#123`:
+2) Branch out from `master` into `fix/some-bug-#123`:
 (Postfixing #123 will associate your PR with the issue #123 and make everyone's life easier =D)
 ```
 git checkout -b fix/some-bug-#123
@@ -41,7 +40,7 @@ git commit "Fix some bug #123"
 git push origin fix/some-bug-#123
 ```
 
-4) Go to [github.com/OpenZeppelin/zeppelin-solidity](https://github.com/OpenZeppelin/zeppelin-solidity) in your web browser and issue a new pull request.
+4) Go to [github.com/OpenZeppelin/openzeppelin-solidity](https://github.com/OpenZeppelin/zeppelin-solidity) in your web browser and issue a new pull request.
 
 *IMPORTANT* Read the PR template very carefully and make sure to follow all the instructions. These instructions 
 refer to some very important conditions that your PR must meet in order to be accepted, such as making sure that all tests pass, JS linting tests pass, solidity linting tests pass, etc.
@@ -52,8 +51,8 @@ refer to some very important conditions that your PR must meet in order to be ac
 
 ## All set!
 
-If you have any questions feel free to post them to github.com/OpenZeppelin/zeppelin-solidity/issues.
+If you have any questions feel free to post them to github.com/OpenZeppelin/openzeppelin-solidity/issues.
 
-Finally, if you're looking to collaborate and want to find easy tasks to start, look at the issues we marked as ["Good first issue"](https://github.com/OpenZeppelin/zeppelin-solidity/labels/good%20first%20issue).
+Finally, if you're looking to collaborate and want to find easy tasks to start, look at the issues we marked as ["Good first issue"](https://github.com/OpenZeppelin/openzeppelin-solidity/labels/good%20first%20issue).
 
 Thanks for your time and code!

README.md

@@ -1,7 +1,7 @@
-# Zeppelin Solidity
-[![NPM Package](https://img.shields.io/npm/v/zeppelin-solidity.svg?style=flat-square)](https://www.npmjs.org/package/zeppelin-solidity)
-[![Build Status](https://img.shields.io/travis/OpenZeppelin/zeppelin-solidity.svg?branch=master&style=flat-square)](https://travis-ci.org/OpenZeppelin/zeppelin-solidity)
-[![Coverage Status](https://img.shields.io/coveralls/github/OpenZeppelin/zeppelin-solidity/master.svg?style=flat-square)](https://coveralls.io/github/OpenZeppelin/zeppelin-solidity?branch=master)
+# OpenZeppelin Solidity
+[![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 is a library for writing secure [Smart Contracts](https://en.wikipedia.org/wiki/Smart_contract) on Ethereum.
 
@@ -13,7 +13,11 @@ With OpenZeppelin, you can build distributed applications, protocols and organiz
 
 ## Getting Started
 
-OpenZeppelin integrates with [Truffle](https://github.com/ConsenSys/truffle), an Ethereum development environment. Please install Truffle and initialize your project with `truffle init`.
+OpenZeppelin integrates with [Truffle](https://github.com/ConsenSys/truffle) and [Embark](https://github.com/embark-framework/embark/).
+
+## truffle
+
+To use with Truffle, first install it and initialize your project with `truffle init`.
 
 ```sh
 npm install -g truffle
@@ -21,28 +25,91 @@ mkdir myproject && cd myproject
 truffle init
 ```
 
-To install the OpenZeppelin library, run the following in your Solidity project root directory:
+## Embark
+
+To use with Embark, first install it and initialize your project with `embark new MyApp`.
+
+```sh
+npm install -g embark
+embark new MyApp
+cd MyApp
+```
+
+## Installing OpenZeppelin
+
+After installing either Framework, to install the OpenZeppelin library, run the following in your Solidity project root directory:
+
 ```sh
 npm init -y
-npm install -E zeppelin-solidity
+npm install -E openzeppelin-solidity
 ```
 
 **Note that OpenZeppelin does not currently follow semantic versioning.** You may encounter breaking changes upon a minor version bump. We recommend pinning the version of OpenZeppelin you use, as done by the `-E` (`--save-exact`) option.
 
-After that, you'll get all the library's contracts in the `node_modules/zeppelin-solidity/contracts` folder. You can use the contracts in the library like so:
+After that, you'll get all the library's contracts in the `node_modules/openzeppelin-solidity/contracts` folder. You can use the contracts in the library like so:
 
-```js
-import 'zeppelin-solidity/contracts/ownership/Ownable.sol';
+```solidity
+import 'openzeppelin-solidity/contracts/ownership/Ownable.sol';
 
 contract MyContract is Ownable {
   ...
 }
 ```
 
+If you are using Embark, you can also import directly from github:
+
+```solidity
+import "github.com/OpenZeppelin/openzeppelin-solidity/contracts/ownership/Ownable.sol#v1.9.0";
+
+contract MyContract is Ownable {
+  ...
+}
+```
+
+## Architecture
+The following provides visibility into how OpenZeppelin's contracts are organized:
+
+- **access** - Smart contracts that enable functionality that can be used for selective restrictions and basic authorization control functions. Includes address whitelisting and signature-based permissions management.
+	- **rbac** - A library used to manage addresses assigned to different user roles and an example Role-Based Access Control (RBAC) interface that demonstrates how to handle setters and getters for roles and addresses.
+- **crowdsale** - A collection of smart contracts used to manage token crowdsales that allow investors to purchase tokens with ETH. Includes a base contract which implements fundamental crowdsale functionality in its simplest form. The base contract can be extended in order to satisfy your crowdsale’s specific requirements.
+	- **distribution** - Includes extensions of the base crowdsale contract which can be used to customize the completion of a crowdsale.
+	- **emission** - Includes extensions of the base crowdsale contract which can be used to mint and manage how tokens are issued to purchasers.
+	- **price** - Includes extensions of the crowdsale contract that can be used to manage changes in token prices.
+	- **validation**  - Includes extensions of the crowdsale contract that can be used to enforce restraints and limit access to token purchases.
+- **examples** - A collection of simple smart contracts that demonstrate how to add new features to base contracts through multiple inheritance.
+- **introspection**  - An interface that can be used to make a contract comply with the ERC-165 standard as well as a contract that implements ERC-165 using a lookup table.
+- **lifecycle** - A collection of base contracts used to manage the existence and behavior of your contracts and their funds.
+- **math** - Libraries with safety checks on operations that throw on errors.
+- **mocks** - A collection of abstract contracts that are primarily used for unit testing. They also serve as good usage examples and demonstrate how to combine contracts with inheritence when developing your own custom applciations.
+- **ownership** - A collection of smart contracts that can be used to manage contract and token ownership
+- **payment** - A collection of smart contracts that can be used to manage payments through escrow arrangements, withdrawals, and claims. Includes support for both single payees and multiple payees.
+- **proposals** - A collection of smart contracts that reflect community Ethereum Improvement Proposals (EIPs). These contracts are under development and standardization. They are not recommended for production, but they are useful for experimentation with pending EIP standards. Go [here](https://github.com/OpenZeppelin/openzeppelin-solidity/wiki/ERC-Process) for more information.
+
+- **token** - A collection of approved ERC standard tokens -- their interfaces and implementations.
+	- **ERC20** - A standard interface for fungible tokens:
+		- *Interfaces* - Includes the ERC-20 token standard basic interface. I.e., what the contract’s ABI can represent.
+		- *Implementations* - Includes ERC-20 token implementations that include all required and some optional ERC-20 functionality.
+	- **ERC721** - A standard interface for non-fungible tokens 
+		- *Interfaces* - Includes the ERC-721 token standard basic interface. I.e., what the contract’s ABI can represent.
+		- *Implementations* - Includes ERC-721 token implementations that include all required and some optional ERC-721 functionality.
+
+## Tests
+Unit test are critical to the OpenZeppelin framework. They help ensure code quality and mitigate against security vulnerabilities. The directory structure within the `/tests` directory corresponds to the `/contracts` directory. OpenZeppelin uses Mocha’s JavaScript testing framework and Chai’s assertion library. To learn more about how to tests are structured, please reference OpenZeppelin’s Testing Guide.
+
+## How To Use And Modify OpenZeppelin Contracts
+When using OpenZeppelin to build your own distributed applications, for security reasons we encourage you NOT to modify the framework’s base contracts, libraries, and interfaces. In order to leverage and extend their functionality, we encourage you to inherit from them or compose them together with your own contracts.
+
+The Solidity programming language supports multiple inheritance. This is very powerful yet it can also be confusing: the more complexity you introduce to your distributed applications through multiple inheritance, the greater your application’s attack surface is.
+
+You’ll notice in the `/mocks` directory there are a collection of abstract contracts used primarily for unit testing purposes that can also be used as the foundation for your own custom implementations. These mock contracts demonstrate how OpenZeppelin’s secure base contracts can be used with multiple inheritance.
+
+To learn more about combining OpenZeppelin contracts with your own custom contracts using multiple inheritance we encourage you to read the following: [On crowdsales and multiple inheritance](https://blog.zeppelin.solutions/on-crowdsales-and-multiple-inheritance-af90c694e35f)
 
 ## Security
 OpenZeppelin is meant to provide secure, 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 problem 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.
+
 If you find a security issue, please email [security@openzeppelin.org](mailto:security@openzeppelin.org).
 
 ## Developer Resources
@@ -56,27 +123,9 @@ Building a distributed application, protocol or organization with OpenZeppelin?
 Interested in contributing to OpenZeppelin?
 
 - Framework proposal and roadmap: https://medium.com/zeppelin-blog/zeppelin-framework-proposal-and-development-roadmap-fdfa9a3a32ab#.iain47pak
-- Issue tracker: https://github.com/OpenZeppelin/zeppelin-solidity/issues
-- Contribution guidelines: https://github.com/OpenZeppelin/zeppelin-solidity/blob/master/CONTRIBUTING.md
-- Wiki: https://github.com/OpenZeppelin/zeppelin-solidity/wiki
-
-## Collaborating organizations and audits by OpenZeppelin
-- [Golem](https://golem.network/)
-- [Mediachain](http://www.mediachain.io/)
-- [Truffle](http://truffleframework.com/)
-- [Firstblood](https://firstblood.io/)
-- [Rootstock](https://www.rsk.co/)
-- [Consensys](https://consensys.net/)
-- [DigixGlobal](https://www.dgx.io/)
-- [Coinfund](https://coinfund.io/)
-- [DemocracyEarth](https://democracy.earth/)
-- [Signatura](https://signatura.co/)
-- [Ether.camp](http://www.ether.camp/)
-- [Aragon](https://aragon.one/)
-- [Wings](https://wings.ai/)
-
-among others...
-
+- Issue tracker: https://github.com/OpenZeppelin/openzeppelin-solidity/issues
+- Contribution guidelines: https://github.com/OpenZeppelin/openzeppelin-solidity/blob/master/CONTRIBUTING.md
+- Wiki: https://github.com/OpenZeppelin/openzeppelin-solidity/wiki
 
 ## License
-Code released under the [MIT License](https://github.com/OpenZeppelin/zeppelin-solidity/blob/master/LICENSE).
+Code released under the [MIT License](https://github.com/OpenZeppelin/openzeppelin-solidity/blob/master/LICENSE).

contracts/.npmignore

@@ -0,0 +1,2 @@
+mocks
+examples

contracts/AddressUtils.sol

@@ -0,0 +1,29 @@
+pragma solidity ^0.4.24;
+
+
+/**
+ * Utility library of inline functions on addresses
+ */
+library AddressUtils {
+
+  /**
+   * Returns whether the target address is a contract
+   * @dev This function will return false if invoked during the constructor of a contract,
+   * as the code is not actually created until after the constructor finishes.
+   * @param _addr address to check
+   * @return whether the target address is a contract
+   */
+  function isContract(address _addr) internal view returns (bool) {
+    uint256 size;
+    // XXX Currently there is no better way to check if there is a contract in an address
+    // than to check the size of the code at that address.
+    // See https://ethereum.stackexchange.com/a/14016/36603
+    // for more details about how this works.
+    // TODO Check this again before the Serenity release, because all addresses will be
+    // contracts then.
+    // solium-disable-next-line security/no-inline-assembly
+    assembly { size := extcodesize(_addr) }
+    return size > 0;
+  }
+
+}

contracts/AutoIncrementing.sol

@@ -0,0 +1,29 @@
+pragma solidity ^0.4.24;
+
+
+/**
+ * @title AutoIncrementing
+ * @author Matt Condon (@shrugs)
+ * @dev Provides an auto-incrementing uint256 id acquired by the `Counter#nextId` getter.
+ * Use this for issuing ERC721Token ids or keeping track of request ids, anything you want, really.
+ *
+ * Include with `using AutoIncrementing for AutoIncrementing.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 AutoIncrementing {
+
+  struct Counter {
+    uint256 prevId; // default: 0
+  }
+
+  function nextId(Counter storage _counter)
+    internal
+    returns (uint256)
+  {
+    _counter.prevId = _counter.prevId + 1;
+    return _counter.prevId;
+  }
+}

contracts/Bounty.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 
 import "./payment/PullPayment.sol";
@@ -30,20 +30,20 @@ contract Bounty is PullPayment, Destructible {
   function createTarget() public returns(Target) {
     Target target = Target(deployContract());
     researchers[target] = msg.sender;
-    TargetCreated(target);
+    emit TargetCreated(target);
     return target;
   }
 
   /**
-   * @dev Sends the contract funds to the researcher that proved the contract is broken.
-   * @param target contract
+   * @dev Transfers the contract funds to the researcher that proved the contract is broken.
+   * @param _target contract
    */
-  function claim(Target target) public {
-    address researcher = researchers[target];
-    require(researcher != 0);
+  function claim(Target _target) public {
+    address researcher = researchers[_target];
+    require(researcher != address(0));
     // Check Target contract invariants
-    require(!target.checkInvariant());
-    asyncSend(researcher, this.balance);
+    require(!_target.checkInvariant());
+    asyncTransfer(researcher, address(this).balance);
     claimed = true;
   }
 

contracts/DayLimit.sol

@@ -1,74 +0,0 @@
-pragma solidity ^0.4.18;
-
-
-/**
- * @title DayLimit
- * @dev Base contract that enables methods to be protected by placing a linear limit (specifiable)
- * on a particular resource per calendar day. Is multiowned to allow the limit to be altered.
- */
-contract DayLimit {
-
-  uint256 public dailyLimit;
-  uint256 public spentToday;
-  uint256 public lastDay;
-
-  /**
-   * @dev Constructor that sets the passed value as a dailyLimit.
-   * @param _limit uint256 to represent the daily limit.
-   */
-  function DayLimit(uint256 _limit) public {
-    dailyLimit = _limit;
-    lastDay = today();
-  }
-
-  /**
-   * @dev sets the daily limit. Does not alter the amount already spent today.
-   * @param _newLimit uint256 to represent the new limit.
-   */
-  function _setDailyLimit(uint256 _newLimit) internal {
-    dailyLimit = _newLimit;
-  }
-
-  /**
-   * @dev Resets the amount already spent today.
-   */
-  function _resetSpentToday() internal {
-    spentToday = 0;
-  }
-
-  /**
-   * @dev Checks to see if there is enough resource to spend today. If true, the resource may be expended.
-   * @param _value uint256 representing the amount of resource to spend.
-   * @return A boolean that is True if the resource was spent and false otherwise.
-   */
-  function underLimit(uint256 _value) internal returns (bool) {
-    // reset the spend limit if we're on a different day to last time.
-    if (today() > lastDay) {
-      spentToday = 0;
-      lastDay = today();
-    }
-    // check to see if there's enough left - if so, subtract and return true.
-    // overflow protection                    // dailyLimit check
-    if (spentToday + _value >= spentToday && spentToday + _value <= dailyLimit) {
-      spentToday += _value;
-      return true;
-    }
-    return false;
-  }
-
-  /**
-   * @dev Private function to determine today's index
-   * @return uint256 of today's index.
-   */
-  function today() private view returns (uint256) {
-    return now / 1 days;
-  }
-
-  /**
-   * @dev Simple modifier for daily limit.
-   */
-  modifier limitedDaily(uint256 _value) {
-    require(underLimit(_value));
-    _;
-  }
-}

contracts/ECRecovery.sol

@@ -1,34 +1,42 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 
 /**
- * @title Eliptic curve signature operations
- *
+ * @title Elliptic curve signature operations
  * @dev Based on https://gist.github.com/axic/5b33912c6f61ae6fd96d6c4a47afde6d
+ * TODO Remove this library once solidity supports passing a signature to ecrecover.
+ * See https://github.com/ethereum/solidity/issues/864
  */
 
 library ECRecovery {
 
   /**
-   * @dev Recover signer address from a message by using his signature
-   * @param hash bytes32 message, the hash is the signed message. What is recovered is the signer address.
-   * @param sig bytes signature, the signature is generated using web3.eth.sign()
+   * @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 _sig bytes signature, the signature is generated using web3.eth.sign()
    */
-  function recover(bytes32 hash, bytes sig) public pure returns (address) {
+  function recover(bytes32 _hash, bytes _sig)
+    internal
+    pure
+    returns (address)
+  {
     bytes32 r;
     bytes32 s;
     uint8 v;
 
-    //Check the signature length
-    if (sig.length != 65) {
+    // Check the signature length
+    if (_sig.length != 65) {
       return (address(0));
     }
 
     // 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(sig, 32))
-      s := mload(add(sig, 64))
-      v := byte(0, mload(add(sig, 96)))
+      r := mload(add(_sig, 32))
+      s := mload(add(_sig, 64))
+      v := byte(0, mload(add(_sig, 96)))
     }
 
     // Version of signature should be 27 or 28, but 0 and 1 are also possible versions
@@ -40,8 +48,25 @@ library ECRecovery {
     if (v != 27 && v != 28) {
       return (address(0));
     } else {
-      return ecrecover(hash, v, r, s);
+      // 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/LimitBalance.sol

@@ -1,11 +1,11 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 
 /**
  * @title LimitBalance
  * @dev Simple contract to limit the balance of child contract.
- * @dev Note this doesn't prevent other contracts to send funds by using selfdestruct(address);
- * @dev See: https://github.com/ConsenSys/smart-contract-best-practices#remember-that-ether-can-be-forcibly-sent-to-an-account
+ * Note this doesn't prevent other contracts to send funds by using selfdestruct(address);
+ * See: https://github.com/ConsenSys/smart-contract-best-practices#remember-that-ether-can-be-forcibly-sent-to-an-account
  */
 contract LimitBalance {
 
@@ -15,7 +15,7 @@ contract LimitBalance {
    * @dev Constructor that sets the passed value as a limit.
    * @param _limit uint256 to represent the limit.
    */
-  function LimitBalance(uint256 _limit) public {
+  constructor(uint256 _limit) public {
     limit = _limit;
   }
 
@@ -23,7 +23,7 @@ contract LimitBalance {
    * @dev Checks if limit was reached. Case true, it throws.
    */
   modifier limitedPayable() {
-    require(this.balance <= limit);
+    require(address(this).balance <= limit);
     _;
 
   }

contracts/MerkleProof.sol

@@ -1,40 +1,39 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 
-/*
+/**
  * @title MerkleProof
- * @dev Merkle proof verification
- * @note Based on https://github.com/ameensol/merkle-tree-solidity/blob/master/src/MerkleProof.sol
+ * @dev Merkle proof verification based on
+ * 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 is sorted.
+   * 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 verifyProof(bytes _proof, bytes32 _root, bytes32 _leaf) public pure returns (bool) {
-    // Check if proof length is a multiple of 32
-    if (_proof.length % 32 != 0) {
-      return false;
-    }
-
-    bytes32 proofElement;
+  function verifyProof(
+    bytes32[] _proof,
+    bytes32 _root,
+    bytes32 _leaf
+  )
+    internal
+    pure
+    returns (bool)
+  {
     bytes32 computedHash = _leaf;
 
-    for (uint256 i = 32; i <= _proof.length; i += 32) {
-      assembly {
-        // Load the current element of the proof
-        proofElement := mload(add(_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(computedHash, proofElement);
+        computedHash = keccak256(abi.encodePacked(computedHash, proofElement));
       } else {
         // Hash(current element of the proof + current computed hash)
-        computedHash = keccak256(proofElement, computedHash);
+        computedHash = keccak256(abi.encodePacked(proofElement, computedHash));
       }
     }
 

contracts/ReentrancyGuard.sol

@@ -1,32 +1,39 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 
 /**
- * @title Helps contracts guard agains reentrancy attacks.
- * @author Remco Bloemen <remco@2π.com>
- * @notice If you mark a function `nonReentrant`, you should also
+ * @title Helps contracts guard against reentrancy attacks.
+ * @author Remco Bloemen <remco@2π.com>, Eenae <alexey@mixbytes.io>
+ * @dev If you mark a function `nonReentrant`, you should also
  * mark it `external`.
  */
 contract ReentrancyGuard {
 
+  /// @dev Constant for unlocked guard state - non-zero to prevent extra gas costs.
+  /// See: https://github.com/OpenZeppelin/openzeppelin-solidity/issues/1056
+  uint private constant REENTRANCY_GUARD_FREE = 1;
+
+  /// @dev Constant for locked guard state
+  uint private constant REENTRANCY_GUARD_LOCKED = 2;
+
   /**
    * @dev We use a single lock for the whole contract.
    */
-  bool private reentrancy_lock = false;
+  uint private reentrancyLock = REENTRANCY_GUARD_FREE;
 
   /**
    * @dev Prevents a contract from calling itself, directly or indirectly.
-   * @notice If you mark a function `nonReentrant`, you should also
-   * mark it `external`. Calling one nonReentrant function from
+   * If you mark a function `nonReentrant`, you should also
+   * mark it `external`. Calling one `nonReentrant` function from
    * another is not supported. Instead, you can implement a
-   * `private` function doing the actual work, and a `external`
+   * `private` function doing the actual work, and an `external`
    * wrapper marked as `nonReentrant`.
    */
   modifier nonReentrant() {
-    require(!reentrancy_lock);
-    reentrancy_lock = true;
+    require(reentrancyLock == REENTRANCY_GUARD_FREE);
+    reentrancyLock = REENTRANCY_GUARD_LOCKED;
     _;
-    reentrancy_lock = false;
+    reentrancyLock = REENTRANCY_GUARD_FREE;
   }
 
 }

contracts/access/SignatureBouncer.sol

@@ -0,0 +1,159 @@
+pragma solidity ^0.4.24;
+
+import "../ownership/Ownable.sol";
+import "../access/rbac/RBAC.sol";
+import "../ECRecovery.sol";
+
+
+/**
+ * @title SignatureBouncer
+ * @author PhABC, Shrugs and aflesher
+ * @dev Bouncer allows users to submit a signature as a permission to do an action.
+ * If the signature is from one of the authorized bouncer addresses, the signature
+ * is valid. The owner of the contract adds/removes bouncers.
+ * Bouncer addresses can be individual servers signing grants or different
+ * users within a decentralized club that have permission to invite other members.
+ * This technique is useful for whitelists and airdrops; instead of putting all
+ * valid addresses on-chain, simply sign a grant of the form
+ * keccak256(abi.encodePacked(`:contractAddress` + `:granteeAddress`)) using a valid bouncer address.
+ * Then restrict access to your crowdsale/whitelist/airdrop using the
+ * `onlyValidSignature` modifier (or implement your own using isValidSignature).
+ * In addition to `onlyValidSignature`, `onlyValidSignatureAndMethod` and
+ * `onlyValidSignatureAndData` can be used to restrict access to only a given method
+ * or a given method with given parameters respectively.
+ * See the tests Bouncer.test.js for specific usage examples.
+ * @notice A method that uses the `onlyValidSignatureAndData` modifier must make the _sig
+ * 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 _sig data and the _sig 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 Ownable, RBAC {
+  using ECRecovery for bytes32;
+
+  string public constant ROLE_BOUNCER = "bouncer";
+  uint constant METHOD_ID_SIZE = 4;
+  // signature size is 65 bytes (tightly packed v + r + s), but gets padded to 96 bytes
+  uint constant SIGNATURE_SIZE = 96;
+
+  /**
+   * @dev requires that a valid signature of a bouncer was provided
+   */
+  modifier onlyValidSignature(bytes _sig)
+  {
+    require(isValidSignature(msg.sender, _sig));
+    _;
+  }
+
+  /**
+   * @dev requires that a valid signature with a specifed method of a bouncer was provided
+   */
+  modifier onlyValidSignatureAndMethod(bytes _sig)
+  {
+    require(isValidSignatureAndMethod(msg.sender, _sig));
+    _;
+  }
+
+  /**
+   * @dev requires that a valid signature with a specifed method and params of a bouncer was provided
+   */
+  modifier onlyValidSignatureAndData(bytes _sig)
+  {
+    require(isValidSignatureAndData(msg.sender, _sig));
+    _;
+  }
+
+  /**
+   * @dev allows the owner to add additional bouncer addresses
+   */
+  function addBouncer(address _bouncer)
+    public
+    onlyOwner
+  {
+    require(_bouncer != address(0));
+    addRole(_bouncer, ROLE_BOUNCER);
+  }
+
+  /**
+   * @dev allows the owner to remove bouncer addresses
+   */
+  function removeBouncer(address _bouncer)
+    public
+    onlyOwner
+  {
+    require(_bouncer != address(0));
+    removeRole(_bouncer, ROLE_BOUNCER);
+  }
+
+  /**
+   * @dev is the signature of `this + sender` from a bouncer?
+   * @return bool
+   */
+  function isValidSignature(address _address, bytes _sig)
+    internal
+    view
+    returns (bool)
+  {
+    return isValidDataHash(
+      keccak256(abi.encodePacked(address(this), _address)),
+      _sig
+    );
+  }
+
+  /**
+   * @dev is the signature of `this + sender + methodId` from a bouncer?
+   * @return bool
+   */
+  function isValidSignatureAndMethod(address _address, bytes _sig)
+    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), _address, data)),
+      _sig
+    );
+  }
+
+  /**
+    * @dev is the signature of `this + sender + methodId + params(s)` from a bouncer?
+    * @notice the _sig parameter of the method being validated must be the "last" parameter
+    * @return bool
+    */
+  function isValidSignatureAndData(address _address, bytes _sig)
+    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), _address, data)),
+      _sig
+    );
+  }
+
+  /**
+   * @dev internal function to convert a hash to an eth signed message
+   * and then recover the signature and check it against the bouncer role
+   * @return bool
+   */
+  function isValidDataHash(bytes32 _hash, bytes _sig)
+    internal
+    view
+    returns (bool)
+  {
+    address signer = _hash
+      .toEthSignedMessageHash()
+      .recover(_sig);
+    return hasRole(signer, ROLE_BOUNCER);
+  }
+}

contracts/access/Whitelist.sol

@@ -0,0 +1,91 @@
+pragma solidity ^0.4.24;
+
+
+import "../ownership/Ownable.sol";
+import "../access/rbac/RBAC.sol";
+
+
+/**
+ * @title Whitelist
+ * @dev The Whitelist contract has a whitelist of addresses, and provides basic authorization control functions.
+ * This simplifies the implementation of "user permissions".
+ */
+contract Whitelist is Ownable, RBAC {
+  string public constant ROLE_WHITELISTED = "whitelist";
+
+  /**
+   * @dev Throws if operator is not whitelisted.
+   * @param _operator address
+   */
+  modifier onlyIfWhitelisted(address _operator) {
+    checkRole(_operator, ROLE_WHITELISTED);
+    _;
+  }
+
+  /**
+   * @dev add an address to the whitelist
+   * @param _operator address
+   * @return true if the address was added to the whitelist, false if the address was already in the whitelist
+   */
+  function addAddressToWhitelist(address _operator)
+    public
+    onlyOwner
+  {
+    addRole(_operator, ROLE_WHITELISTED);
+  }
+
+  /**
+   * @dev getter to determine if address is in whitelist
+   */
+  function whitelist(address _operator)
+    public
+    view
+    returns (bool)
+  {
+    return hasRole(_operator, ROLE_WHITELISTED);
+  }
+
+  /**
+   * @dev add addresses to the whitelist
+   * @param _operators addresses
+   * @return true if at least one address was added to the whitelist,
+   * false if all addresses were already in the whitelist
+   */
+  function addAddressesToWhitelist(address[] _operators)
+    public
+    onlyOwner
+  {
+    for (uint256 i = 0; i < _operators.length; i++) {
+      addAddressToWhitelist(_operators[i]);
+    }
+  }
+
+  /**
+   * @dev remove an address from the whitelist
+   * @param _operator address
+   * @return true if the address was removed from the whitelist,
+   * false if the address wasn't in the whitelist in the first place
+   */
+  function removeAddressFromWhitelist(address _operator)
+    public
+    onlyOwner
+  {
+    removeRole(_operator, ROLE_WHITELISTED);
+  }
+
+  /**
+   * @dev remove addresses from the whitelist
+   * @param _operators addresses
+   * @return true if at least one address was removed from the whitelist,
+   * false if all addresses weren't in the whitelist in the first place
+   */
+  function removeAddressesFromWhitelist(address[] _operators)
+    public
+    onlyOwner
+  {
+    for (uint256 i = 0; i < _operators.length; i++) {
+      removeAddressFromWhitelist(_operators[i]);
+    }
+  }
+
+}

contracts/access/rbac/RBAC.sol

@@ -0,0 +1,106 @@
+pragma solidity ^0.4.24;
+
+import "./Roles.sol";
+
+
+/**
+ * @title RBAC (Role-Based Access Control)
+ * @author Matt Condon (@Shrugs)
+ * @dev Stores and provides setters and getters for roles and addresses.
+ * Supports unlimited numbers of roles and addresses.
+ * See //contracts/mocks/RBACMock.sol for an example of usage.
+ * This RBAC method uses strings to key roles. It may be beneficial
+ * for you to write your own implementation of this interface using Enums or similar.
+ */
+contract RBAC {
+  using Roles for Roles.Role;
+
+  mapping (string => Roles.Role) private roles;
+
+  event RoleAdded(address indexed operator, string role);
+  event RoleRemoved(address indexed operator, string role);
+
+  /**
+   * @dev reverts if addr does not have role
+   * @param _operator address
+   * @param _role the name of the role
+   * // reverts
+   */
+  function checkRole(address _operator, string _role)
+    public
+    view
+  {
+    roles[_role].check(_operator);
+  }
+
+  /**
+   * @dev determine if addr has role
+   * @param _operator address
+   * @param _role the name of the role
+   * @return bool
+   */
+  function hasRole(address _operator, string _role)
+    public
+    view
+    returns (bool)
+  {
+    return roles[_role].has(_operator);
+  }
+
+  /**
+   * @dev add a role to an address
+   * @param _operator address
+   * @param _role the name of the role
+   */
+  function addRole(address _operator, string _role)
+    internal
+  {
+    roles[_role].add(_operator);
+    emit RoleAdded(_operator, _role);
+  }
+
+  /**
+   * @dev remove a role from an address
+   * @param _operator address
+   * @param _role the name of the role
+   */
+  function removeRole(address _operator, string _role)
+    internal
+  {
+    roles[_role].remove(_operator);
+    emit RoleRemoved(_operator, _role);
+  }
+
+  /**
+   * @dev modifier to scope access to a single role (uses msg.sender as addr)
+   * @param _role the name of the role
+   * // reverts
+   */
+  modifier onlyRole(string _role)
+  {
+    checkRole(msg.sender, _role);
+    _;
+  }
+
+  /**
+   * @dev modifier to scope access to a set of roles (uses msg.sender as addr)
+   * @param _roles the names of the roles to scope access to
+   * // reverts
+   *
+   * @TODO - when solidity supports dynamic arrays as arguments to modifiers, provide this
+   *  see: https://github.com/ethereum/solidity/issues/2467
+   */
+  // modifier onlyRoles(string[] _roles) {
+  //     bool hasAnyRole = false;
+  //     for (uint8 i = 0; i < _roles.length; i++) {
+  //         if (hasRole(msg.sender, _roles[i])) {
+  //             hasAnyRole = true;
+  //             break;
+  //         }
+  //     }
+
+  //     require(hasAnyRole);
+
+  //     _;
+  // }
+}

contracts/access/rbac/Roles.sol

@@ -1,11 +1,11 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 
 /**
  * @title Roles
  * @author Francisco Giordano (@frangio)
  * @dev Library for managing addresses assigned to a Role.
- *      See RBAC.sol for example usage.
+ * See RBAC.sol for example usage.
  */
 library Roles {
   struct Role {
@@ -15,41 +15,41 @@ library Roles {
   /**
    * @dev give an address access to this role
    */
-  function add(Role storage role, address addr)
+  function add(Role storage _role, address _addr)
     internal
   {
-    role.bearer[addr] = true;
+    _role.bearer[_addr] = true;
   }
 
   /**
    * @dev remove an address' access to this role
    */
-  function remove(Role storage role, address addr)
+  function remove(Role storage _role, address _addr)
     internal
   {
-    role.bearer[addr] = false;
+    _role.bearer[_addr] = false;
   }
 
   /**
    * @dev check if an address has this role
    * // reverts
    */
-  function check(Role storage role, address addr)
-    view
+  function check(Role storage _role, address _addr)
     internal
+    view
   {
-    require(has(role, addr));
+    require(has(_role, _addr));
   }
 
   /**
    * @dev check if an address has this role
    * @return bool
    */
-  function has(Role storage role, address addr)
-    view
+  function has(Role storage _role, address _addr)
     internal
+    view
     returns (bool)
   {
-    return role.bearer[addr];
+    return _role.bearer[_addr];
   }
 }

contracts/crowdsale/Crowdsale.sol

@@ -1,7 +1,9 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "../token/ERC20/ERC20.sol";
 import "../math/SafeMath.sol";
+import "../token/ERC20/SafeERC20.sol";
+
 
 /**
  * @title Crowdsale
@@ -10,14 +12,14 @@ import "../math/SafeMath.sol";
  * 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 / overriden.
- * The internal interface conforms the extensible and modifiable surface of crowdsales. Override 
- * the methods to add functionality. Consider using 'super' where appropiate to concatenate
+ * the base architecture for crowdsales. They are *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 {
   using SafeMath for uint256;
+  using SafeERC20 for ERC20;
 
   // The token being sold
   ERC20 public token;
@@ -25,7 +27,10 @@ contract Crowdsale {
   // Address where funds are collected
   address public wallet;
 
-  // How many token units a buyer gets per wei
+  // 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 DetailedERC20 token with 3 decimals called TOK
+  // 1 wei will give you 1 unit, or 0.001 TOK.
   uint256 public rate;
 
   // Amount of wei raised
@@ -38,14 +43,19 @@ contract Crowdsale {
    * @param value weis paid for purchase
    * @param amount amount of tokens purchased
    */
-  event TokenPurchase(address indexed purchaser, address indexed beneficiary, uint256 value, uint256 amount);
+  event TokenPurchase(
+    address indexed purchaser,
+    address indexed beneficiary,
+    uint256 value,
+    uint256 amount
+  );
 
   /**
    * @param _rate Number of token units a buyer gets per wei
    * @param _wallet Address where collected funds will be forwarded to
    * @param _token Address of the token being sold
    */
-  function Crowdsale(uint256 _rate, address _wallet, ERC20 _token) public {
+  constructor(uint256 _rate, address _wallet, ERC20 _token) public {
     require(_rate > 0);
     require(_wallet != address(0));
     require(_token != address(0));
@@ -82,7 +92,12 @@ contract Crowdsale {
     weiRaised = weiRaised.add(weiAmount);
 
     _processPurchase(_beneficiary, tokens);
-    TokenPurchase(msg.sender, _beneficiary, weiAmount, tokens);
+    emit TokenPurchase(
+      msg.sender,
+      _beneficiary,
+      weiAmount,
+      tokens
+    );
 
     _updatePurchasingState(_beneficiary, weiAmount);
 
@@ -95,11 +110,19 @@ contract Crowdsale {
   // -----------------------------------------
 
   /**
-   * @dev Validation of an incoming purchase. Use require statemens to revert state when conditions are not met. Use super to concatenate validations.
+   * @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 {
+  function _preValidatePurchase(
+    address _beneficiary,
+    uint256 _weiAmount
+  )
+    internal
+  {
     require(_beneficiary != address(0));
     require(_weiAmount != 0);
   }
@@ -109,7 +132,12 @@ contract Crowdsale {
    * @param _beneficiary Address performing the token purchase
    * @param _weiAmount Value in wei involved in the purchase
    */
-  function _postValidatePurchase(address _beneficiary, uint256 _weiAmount) internal {
+  function _postValidatePurchase(
+    address _beneficiary,
+    uint256 _weiAmount
+  )
+    internal
+  {
     // optional override
   }
 
@@ -118,8 +146,13 @@ contract Crowdsale {
    * @param _beneficiary Address performing the token purchase
    * @param _tokenAmount Number of tokens to be emitted
    */
-  function _deliverTokens(address _beneficiary, uint256 _tokenAmount) internal {
-    token.transfer(_beneficiary, _tokenAmount);
+  function _deliverTokens(
+    address _beneficiary,
+    uint256 _tokenAmount
+  )
+    internal
+  {
+    token.safeTransfer(_beneficiary, _tokenAmount);
   }
 
   /**
@@ -127,7 +160,12 @@ contract Crowdsale {
    * @param _beneficiary Address receiving the tokens
    * @param _tokenAmount Number of tokens to be purchased
    */
-  function _processPurchase(address _beneficiary, uint256 _tokenAmount) internal {
+  function _processPurchase(
+    address _beneficiary,
+    uint256 _tokenAmount
+  )
+    internal
+  {
     _deliverTokens(_beneficiary, _tokenAmount);
   }
 
@@ -136,7 +174,12 @@ contract Crowdsale {
    * @param _beneficiary Address receiving the tokens
    * @param _weiAmount Value in wei involved in the purchase
    */
-  function _updatePurchasingState(address _beneficiary, uint256 _weiAmount) internal {
+  function _updatePurchasingState(
+    address _beneficiary,
+    uint256 _weiAmount
+  )
+    internal
+  {
     // optional override
   }
 
@@ -145,7 +188,9 @@ contract Crowdsale {
    * @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) {
+  function _getTokenAmount(uint256 _weiAmount)
+    internal view returns (uint256)
+  {
     return _weiAmount.mul(rate);
   }
 

contracts/crowdsale/distribution/FinalizableCrowdsale.sol

@@ -1,15 +1,16 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "../../math/SafeMath.sol";
 import "../../ownership/Ownable.sol";
 import "../validation/TimedCrowdsale.sol";
 
+
 /**
  * @title FinalizableCrowdsale
  * @dev Extension of Crowdsale where an owner can do extra work
  * after finishing.
  */
-contract FinalizableCrowdsale is TimedCrowdsale, Ownable {
+contract FinalizableCrowdsale is Ownable, TimedCrowdsale {
   using SafeMath for uint256;
 
   bool public isFinalized = false;
@@ -20,12 +21,12 @@ contract FinalizableCrowdsale is TimedCrowdsale, Ownable {
    * @dev Must be called after crowdsale ends, to do some extra finalization
    * work. Calls the contract's finalization function.
    */
-  function finalize() onlyOwner public {
+  function finalize() public onlyOwner {
     require(!isFinalized);
     require(hasClosed());
 
     finalization();
-    Finalized();
+    emit Finalized();
 
     isFinalized = true;
   }
@@ -37,4 +38,5 @@ contract FinalizableCrowdsale is TimedCrowdsale, Ownable {
    */
   function finalization() internal {
   }
+
 }

contracts/crowdsale/distribution/PostDeliveryCrowdsale.sol

@@ -1,9 +1,10 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "../validation/TimedCrowdsale.sol";
 import "../../token/ERC20/ERC20.sol";
 import "../../math/SafeMath.sol";
 
+
 /**
  * @title PostDeliveryCrowdsale
  * @dev Crowdsale that locks tokens from withdrawal until it ends.
@@ -13,15 +14,6 @@ contract PostDeliveryCrowdsale is TimedCrowdsale {
 
   mapping(address => uint256) public balances;
 
-  /**
-   * @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 Withdraw tokens only after crowdsale ends.
    */
@@ -32,4 +24,19 @@ contract PostDeliveryCrowdsale is TimedCrowdsale {
     balances[msg.sender] = 0;
     _deliverTokens(msg.sender, amount);
   }
+
+  /**
+   * @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);
+  }
+
 }

contracts/crowdsale/distribution/RefundableCrowdsale.sol

@@ -1,16 +1,15 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 
 import "../../math/SafeMath.sol";
 import "./FinalizableCrowdsale.sol";
-import "./utils/RefundVault.sol";
+import "../../payment/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.
- * Uses a RefundVault as the crowdsale's vault.
  */
 contract RefundableCrowdsale is FinalizableCrowdsale {
   using SafeMath for uint256;
@@ -18,16 +17,16 @@ contract RefundableCrowdsale is FinalizableCrowdsale {
   // minimum amount of funds to be raised in weis
   uint256 public goal;
 
-  // refund vault used to hold funds while crowdsale is running
-  RefundVault public vault;
+  // refund escrow used to hold funds while crowdsale is running
+  RefundEscrow private escrow;
 
   /**
-   * @dev Constructor, creates RefundVault. 
+   * @dev Constructor, creates RefundEscrow.
    * @param _goal Funding goal
    */
-  function RefundableCrowdsale(uint256 _goal) public {
+  constructor(uint256 _goal) public {
     require(_goal > 0);
-    vault = new RefundVault(wallet);
+    escrow = new RefundEscrow(wallet);
     goal = _goal;
   }
 
@@ -38,11 +37,11 @@ contract RefundableCrowdsale is FinalizableCrowdsale {
     require(isFinalized);
     require(!goalReached());
 
-    vault.refund(msg.sender);
+    escrow.withdraw(msg.sender);
   }
 
   /**
-   * @dev Checks whether funding goal was reached. 
+   * @dev Checks whether funding goal was reached.
    * @return Whether funding goal was reached
    */
   function goalReached() public view returns (bool) {
@@ -50,23 +49,24 @@ contract RefundableCrowdsale is FinalizableCrowdsale {
   }
 
   /**
-   * @dev vault finalization task, called when owner calls finalize()
+   * @dev escrow finalization task, called when owner calls finalize()
    */
   function finalization() internal {
     if (goalReached()) {
-      vault.close();
+      escrow.close();
+      escrow.beneficiaryWithdraw();
     } else {
-      vault.enableRefunds();
+      escrow.enableRefunds();
     }
 
     super.finalization();
   }
 
   /**
-   * @dev Overrides Crowdsale fund forwarding, sending funds to vault.
+   * @dev Overrides Crowdsale fund forwarding, sending funds to escrow.
    */
   function _forwardFunds() internal {
-    vault.deposit.value(msg.value)(msg.sender);
+    escrow.deposit.value(msg.value)(msg.sender);
   }
 
 }

contracts/crowdsale/distribution/utils/RefundVault.sol

@@ -1,66 +0,0 @@
-pragma solidity ^0.4.18;
-
-import "../../../math/SafeMath.sol";
-import "../../../ownership/Ownable.sol";
-
-
-/**
- * @title RefundVault
- * @dev This contract is used for storing funds while a crowdsale
- * is in progress. Supports refunding the money if crowdsale fails,
- * and forwarding it if crowdsale is successful.
- */
-contract RefundVault is Ownable {
-  using SafeMath for uint256;
-
-  enum State { Active, Refunding, Closed }
-
-  mapping (address => uint256) public deposited;
-  address public wallet;
-  State public state;
-
-  event Closed();
-  event RefundsEnabled();
-  event Refunded(address indexed beneficiary, uint256 weiAmount);
-
-  /**
-   * @param _wallet Vault address
-   */
-  function RefundVault(address _wallet) public {
-    require(_wallet != address(0));
-    wallet = _wallet;
-    state = State.Active;
-  }
-
-  /**
-   * @param investor Investor address
-   */
-  function deposit(address investor) onlyOwner public payable {
-    require(state == State.Active);
-    deposited[investor] = deposited[investor].add(msg.value);
-  }
-
-  function close() onlyOwner public {
-    require(state == State.Active);
-    state = State.Closed;
-    Closed();
-    wallet.transfer(this.balance);
-  }
-
-  function enableRefunds() onlyOwner public {
-    require(state == State.Active);
-    state = State.Refunding;
-    RefundsEnabled();
-  }
-
-  /**
-   * @param investor Investor address
-   */
-  function refund(address investor) public {
-    require(state == State.Refunding);
-    uint256 depositedValue = deposited[investor];
-    deposited[investor] = 0;
-    investor.transfer(depositedValue);
-    Refunded(investor, depositedValue);
-  }
-}

contracts/crowdsale/emission/AllowanceCrowdsale.sol

@@ -1,7 +1,9 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "../Crowdsale.sol";
 import "../../token/ERC20/ERC20.sol";
+import "../../token/ERC20/ERC20Basic.sol";
+import "../../token/ERC20/SafeERC20.sol";
 import "../../math/SafeMath.sol";
 
 
@@ -11,14 +13,15 @@ import "../../math/SafeMath.sol";
  */
 contract AllowanceCrowdsale is Crowdsale {
   using SafeMath for uint256;
+  using SafeERC20 for ERC20;
 
   address public tokenWallet;
 
   /**
-   * @dev Constructor, takes token wallet address. 
+   * @dev Constructor, takes token wallet address.
    * @param _tokenWallet Address holding the tokens, which has approved allowance to the crowdsale
    */
-  function AllowanceCrowdsale(address _tokenWallet) public {
+  constructor(address _tokenWallet) public {
     require(_tokenWallet != address(0));
     tokenWallet = _tokenWallet;
   }
@@ -36,7 +39,12 @@ contract AllowanceCrowdsale is Crowdsale {
    * @param _beneficiary Token purchaser
    * @param _tokenAmount Amount of tokens purchased
    */
-  function _deliverTokens(address _beneficiary, uint256 _tokenAmount) internal {
-    token.transferFrom(tokenWallet, _beneficiary, _tokenAmount);
+  function _deliverTokens(
+    address _beneficiary,
+    uint256 _tokenAmount
+  )
+    internal
+  {
+    token.safeTransferFrom(tokenWallet, _beneficiary, _tokenAmount);
   }
 }

contracts/crowdsale/emission/MintedCrowdsale.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "../Crowdsale.sol";
 import "../../token/ERC20/MintableToken.sol";
@@ -7,16 +7,22 @@ import "../../token/ERC20/MintableToken.sol";
 /**
  * @title MintedCrowdsale
  * @dev Extension of Crowdsale contract whose tokens are minted in each purchase.
- * Token ownership should be transferred to MintedCrowdsale for minting. 
+ * Token ownership should be transferred to MintedCrowdsale for minting.
  */
 contract MintedCrowdsale is 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 {
-    require(MintableToken(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(MintableToken(address(token)).mint(_beneficiary, _tokenAmount));
   }
 }

contracts/crowdsale/price/IncreasingPriceCrowdsale.sol

@@ -1,11 +1,12 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "../validation/TimedCrowdsale.sol";
 import "../../math/SafeMath.sol";
 
+
 /**
  * @title IncreasingPriceCrowdsale
- * @dev Extension of Crowdsale contract that increases the price of tokens linearly in time. 
+ * @dev Extension of Crowdsale contract that increases the price of tokens linearly in time.
  * 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.
  */
@@ -16,11 +17,11 @@ contract IncreasingPriceCrowdsale is TimedCrowdsale {
   uint256 public finalRate;
 
   /**
-   * @dev Constructor, takes intial and final rates of tokens received per wei contributed.
+   * @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 IncreasingPriceCrowdsale(uint256 _initialRate, uint256 _finalRate) public {
+  constructor(uint256 _initialRate, uint256 _finalRate) public {
     require(_initialRate >= _finalRate);
     require(_finalRate > 0);
     initialRate = _initialRate;
@@ -28,12 +29,13 @@ contract IncreasingPriceCrowdsale is TimedCrowdsale {
   }
 
   /**
-   * @dev Returns the rate of tokens per wei at the present time. 
-   * Note that, as price _increases_ with time, the rate _decreases_. 
+   * @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) {
-    uint256 elapsedTime = now.sub(openingTime);
+    // 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));
@@ -44,7 +46,9 @@ contract IncreasingPriceCrowdsale is TimedCrowdsale {
    * @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) {
+  function _getTokenAmount(uint256 _weiAmount)
+    internal view returns (uint256)
+  {
     uint256 currentRate = getCurrentRate();
     return currentRate.mul(_weiAmount);
   }

contracts/crowdsale/validation/CappedCrowdsale.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "../../math/SafeMath.sol";
 import "../Crowdsale.sol";
@@ -17,13 +17,13 @@ contract CappedCrowdsale is Crowdsale {
    * @dev Constructor, takes maximum amount of wei accepted in the crowdsale.
    * @param _cap Max amount of wei to be contributed
    */
-  function CappedCrowdsale(uint256 _cap) public {
+  constructor(uint256 _cap) public {
     require(_cap > 0);
     cap = _cap;
   }
 
   /**
-   * @dev Checks whether the cap has been reached. 
+   * @dev Checks whether the cap has been reached.
    * @return Whether the cap was reached
    */
   function capReached() public view returns (bool) {
@@ -35,7 +35,12 @@ contract CappedCrowdsale is Crowdsale {
    * @param _beneficiary Token purchaser
    * @param _weiAmount Amount of wei contributed
    */
-  function _preValidatePurchase(address _beneficiary, uint256 _weiAmount) internal {
+  function _preValidatePurchase(
+    address _beneficiary,
+    uint256 _weiAmount
+  )
+    internal
+  {
     super._preValidatePurchase(_beneficiary, _weiAmount);
     require(weiRaised.add(_weiAmount) <= cap);
   }

contracts/crowdsale/validation/IndividuallyCappedCrowdsale.sol

@@ -1,4 +1,4 @@
-pragma solidity ^ 0.4.18;
+pragma solidity ^0.4.24;
 
 import "../../math/SafeMath.sol";
 import "../Crowdsale.sol";
@@ -9,7 +9,7 @@ import "../../ownership/Ownable.sol";
  * @title IndividuallyCappedCrowdsale
  * @dev Crowdsale with per-user caps.
  */
-contract IndividuallyCappedCrowdsale is Crowdsale, Ownable {
+contract IndividuallyCappedCrowdsale is Ownable, Crowdsale {
   using SafeMath for uint256;
 
   mapping(address => uint256) public contributions;
@@ -29,14 +29,20 @@ contract IndividuallyCappedCrowdsale is Crowdsale, Ownable {
    * @param _beneficiaries List of addresses to be capped
    * @param _cap Wei limit for individual contribution
    */
-  function setGroupCap(address[] _beneficiaries, uint256 _cap) external onlyOwner {
+  function setGroupCap(
+    address[] _beneficiaries,
+    uint256 _cap
+  )
+    external
+    onlyOwner
+  {
     for (uint256 i = 0; i < _beneficiaries.length; i++) {
       caps[_beneficiaries[i]] = _cap;
     }
   }
 
   /**
-   * @dev Returns the cap of a specific user. 
+   * @dev Returns the cap of a specific user.
    * @param _beneficiary Address whose cap is to be checked
    * @return Current cap for individual user
    */
@@ -49,7 +55,9 @@ contract IndividuallyCappedCrowdsale is Crowdsale, Ownable {
    * @param _beneficiary Address of contributor
    * @return User contribution so far
    */
-  function getUserContribution(address _beneficiary) public view returns (uint256) {
+  function getUserContribution(address _beneficiary)
+    public view returns (uint256)
+  {
     return contributions[_beneficiary];
   }
 
@@ -58,7 +66,12 @@ contract IndividuallyCappedCrowdsale is Crowdsale, Ownable {
    * @param _beneficiary Token purchaser
    * @param _weiAmount Amount of wei contributed
    */
-  function _preValidatePurchase(address _beneficiary, uint256 _weiAmount) internal {
+  function _preValidatePurchase(
+    address _beneficiary,
+    uint256 _weiAmount
+  )
+    internal
+  {
     super._preValidatePurchase(_beneficiary, _weiAmount);
     require(contributions[_beneficiary].add(_weiAmount) <= caps[_beneficiary]);
   }
@@ -68,7 +81,12 @@ contract IndividuallyCappedCrowdsale is Crowdsale, Ownable {
    * @param _beneficiary Token purchaser
    * @param _weiAmount Amount of wei contributed
    */
-  function _updatePurchasingState(address _beneficiary, uint256 _weiAmount) internal {
+  function _updatePurchasingState(
+    address _beneficiary,
+    uint256 _weiAmount
+  )
+    internal
+  {
     super._updatePurchasingState(_beneficiary, _weiAmount);
     contributions[_beneficiary] = contributions[_beneficiary].add(_weiAmount);
   }

contracts/crowdsale/validation/TimedCrowdsale.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "../../math/SafeMath.sol";
 import "../Crowdsale.sol";
@@ -15,10 +15,11 @@ contract TimedCrowdsale is Crowdsale {
   uint256 public closingTime;
 
   /**
-   * @dev Reverts if not in crowdsale time range. 
+   * @dev Reverts if not in crowdsale time range.
    */
   modifier onlyWhileOpen {
-    require(now >= openingTime && now <= closingTime);
+    // solium-disable-next-line security/no-block-members
+    require(block.timestamp >= openingTime && block.timestamp <= closingTime);
     _;
   }
 
@@ -27,8 +28,9 @@ contract TimedCrowdsale is Crowdsale {
    * @param _openingTime Crowdsale opening time
    * @param _closingTime Crowdsale closing time
    */
-  function TimedCrowdsale(uint256 _openingTime, uint256 _closingTime) public {
-    require(_openingTime >= now);
+  constructor(uint256 _openingTime, uint256 _closingTime) public {
+    // solium-disable-next-line security/no-block-members
+    require(_openingTime >= block.timestamp);
     require(_closingTime >= _openingTime);
 
     openingTime = _openingTime;
@@ -40,15 +42,22 @@ contract TimedCrowdsale is Crowdsale {
    * @return Whether crowdsale period has elapsed
    */
   function hasClosed() public view returns (bool) {
-    return now > closingTime;
+    // solium-disable-next-line security/no-block-members
+    return block.timestamp > 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 {
+  function _preValidatePurchase(
+    address _beneficiary,
+    uint256 _weiAmount
+  )
+    internal
+    onlyWhileOpen
+  {
     super._preValidatePurchase(_beneficiary, _weiAmount);
   }
 

contracts/crowdsale/validation/WhitelistedCrowdsale.sol

@@ -1,57 +1,26 @@
-pragma solidity ^ 0.4.18;
+pragma solidity ^0.4.24;
 
 import "../Crowdsale.sol";
-import "../../ownership/Ownable.sol";
+import "../../access/Whitelist.sol";
 
 
 /**
  * @title WhitelistedCrowdsale
  * @dev Crowdsale in which only whitelisted users can contribute.
  */
-contract WhitelistedCrowdsale is Crowdsale, Ownable {
-
-  mapping(address => bool) public whitelist;
-
-  /**
-   * @dev Reverts if beneficiary is not whitelisted. Can be used when extending this contract.
-   */
-  modifier isWhitelisted(address _beneficiary) {
-    require(whitelist[_beneficiary]);
-    _;
-  }
-
-  /**
-   * @dev Adds single address to whitelist.
-   * @param _beneficiary Address to be added to the whitelist
-   */
-  function addToWhitelist(address _beneficiary) external onlyOwner {
-    whitelist[_beneficiary] = true;
-  }
-  
-  /**
-   * @dev Adds list of addresses to whitelist. Not overloaded due to limitations with truffle testing. 
-   * @param _beneficiaries Addresses to be added to the whitelist
-   */
-  function addManyToWhitelist(address[] _beneficiaries) external onlyOwner {
-    for (uint256 i = 0; i < _beneficiaries.length; i++) {
-      whitelist[_beneficiaries[i]] = true;
-    }
-  }
-
-  /**
-   * @dev Removes single address from whitelist. 
-   * @param _beneficiary Address to be removed to the whitelist
-   */
-  function removeFromWhitelist(address _beneficiary) external onlyOwner {
-    whitelist[_beneficiary] = false;
-  }
-
+contract WhitelistedCrowdsale is Whitelist, Crowdsale {
   /**
    * @dev Extend parent behavior requiring beneficiary to be in whitelist.
    * @param _beneficiary Token beneficiary
    * @param _weiAmount Amount of wei contributed
    */
-  function _preValidatePurchase(address _beneficiary, uint256 _weiAmount) internal isWhitelisted(_beneficiary) {
+  function _preValidatePurchase(
+    address _beneficiary,
+    uint256 _weiAmount
+  )
+    internal
+    onlyIfWhitelisted(_beneficiary)
+  {
     super._preValidatePurchase(_beneficiary, _weiAmount);
   }
 

contracts/examples/RBACWithAdmin.sol

@@ -0,0 +1,66 @@
+pragma solidity ^0.4.24;
+
+import "../access/rbac/RBAC.sol";
+
+
+/**
+ * @title RBACWithAdmin
+ * @author Matt Condon (@Shrugs)
+ * @dev It's recommended that you define constants in the contract,
+ * like ROLE_ADMIN below, to avoid typos.
+ * @notice RBACWithAdmin is probably too expansive and powerful for your
+ * application; an admin is actually able to change any address to any role
+ * which is a very large API surface. It's recommended that you follow a strategy
+ * of strictly defining the abilities of your roles
+ * and the API-surface of your contract.
+ * This is just an example for example's sake.
+ */
+contract RBACWithAdmin is RBAC {
+  /**
+   * A constant role name for indicating admins.
+   */
+  string public constant ROLE_ADMIN = "admin";
+
+  /**
+   * @dev modifier to scope access to admins
+   * // reverts
+   */
+  modifier onlyAdmin()
+  {
+    checkRole(msg.sender, ROLE_ADMIN);
+    _;
+  }
+
+  /**
+   * @dev constructor. Sets msg.sender as admin by default
+   */
+  constructor()
+    public
+  {
+    addRole(msg.sender, ROLE_ADMIN);
+  }
+
+  /**
+   * @dev add a role to an address
+   * @param _addr address
+   * @param _roleName the name of the role
+   */
+  function adminAddRole(address _addr, string _roleName)
+    public
+    onlyAdmin
+  {
+    addRole(_addr, _roleName);
+  }
+
+  /**
+   * @dev remove a role from an address
+   * @param _addr address
+   * @param _roleName the name of the role
+   */
+  function adminRemoveRole(address _addr, string _roleName)
+    public
+    onlyAdmin
+  {
+    removeRole(_addr, _roleName);
+  }
+}

contracts/examples/SampleCrowdsale.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "../crowdsale/validation/CappedCrowdsale.sol";
 import "../crowdsale/distribution/RefundableCrowdsale.sol";
@@ -13,9 +13,9 @@ import "../token/ERC20/MintableToken.sol";
  */
 contract SampleCrowdsaleToken is MintableToken {
 
-  string public constant name = "Sample Crowdsale Token"; // solium-disable-line uppercase
-  string public constant symbol = "SCT"; // solium-disable-line uppercase
-  uint8 public constant decimals = 18; // solium-disable-line uppercase
+  string public constant name = "Sample Crowdsale Token";
+  string public constant symbol = "SCT";
+  uint8 public constant decimals = 18;
 
 }
 
@@ -31,9 +31,23 @@ contract SampleCrowdsaleToken is MintableToken {
  * 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 {
 
-  function SampleCrowdsale(uint256 _openingTime, uint256 _closingTime, uint256 _rate, address _wallet, uint256 _cap, MintableToken _token, uint256 _goal) public
+  constructor(
+    uint256 _openingTime,
+    uint256 _closingTime,
+    uint256 _rate,
+    address _wallet,
+    uint256 _cap,
+    MintableToken _token,
+    uint256 _goal
+  )
+    public
     Crowdsale(_rate, _wallet, _token)
     CappedCrowdsale(_cap)
     TimedCrowdsale(_openingTime, _closingTime)

contracts/examples/SimpleSavingsWallet.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.24;
 
 import "../ownership/Heritable.sol";
 
@@ -19,22 +19,22 @@ contract SimpleSavingsWallet is Heritable {
   event Received(address indexed payer, uint256 amount, uint256 balance);
 
 
-  function SimpleSavingsWallet(uint256 _heartbeatTimeout) Heritable(_heartbeatTimeout) public {}
-  
+  constructor(uint256 _heartbeatTimeout) Heritable(_heartbeatTimeout) public {}
+
   /**
    * @dev wallet can receive funds.
    */
-  function () public payable {
-    Received(msg.sender, msg.value, this.balance);
+  function () external payable {
+    emit Received(msg.sender, msg.value, address(this).balance);
   }
 
   /**
    * @dev wallet can send funds
    */
-  function sendTo(address payee, uint256 amount) public onlyOwner {
-    require(payee != 0 && payee != address(this));
-    require(amount > 0);
-    payee.transfer(amount);
-    Sent(payee, amount, this.balance);
+  function sendTo(address _payee, uint256 _amount) public onlyOwner {
+    require(_payee != address(0) && _payee != address(this));
+    require(_amount > 0);
+    _payee.transfer(_amount);
+    emit Sent(_payee, _amount, address(this).balance);
   }
 }

contracts/examples/SimpleToken.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 
 import "../token/ERC20/StandardToken.sol";
@@ -12,19 +12,19 @@ import "../token/ERC20/StandardToken.sol";
  */
 contract SimpleToken is StandardToken {
 
-  string public constant name = "SimpleToken"; // solium-disable-line uppercase
-  string public constant symbol = "SIM"; // solium-disable-line uppercase
-  uint8 public constant decimals = 18; // solium-disable-line uppercase
+  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.
    */
-  function SimpleToken() public {
+  constructor() public {
     totalSupply_ = INITIAL_SUPPLY;
     balances[msg.sender] = INITIAL_SUPPLY;
-    Transfer(0x0, msg.sender, INITIAL_SUPPLY);
+    emit Transfer(address(0), msg.sender, INITIAL_SUPPLY);
   }
 
 }

contracts/introspection/ERC165.sol

@@ -0,0 +1,20 @@
+pragma solidity ^0.4.24;
+
+
+/**
+ * @title ERC165
+ * @dev https://github.com/ethereum/EIPs/blob/master/EIPS/eip-165.md
+ */
+interface ERC165 {
+
+  /**
+   * @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/introspection/SupportsInterfaceWithLookup.sol

@@ -0,0 +1,54 @@
+pragma solidity ^0.4.24;
+
+import "./ERC165.sol";
+
+
+/**
+ * @title SupportsInterfaceWithLookup
+ * @author Matt Condon (@shrugs)
+ * @dev Implements ERC165 using a lookup table.
+ */
+contract SupportsInterfaceWithLookup is ERC165 {
+
+  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) internal supportedInterfaces;
+
+  /**
+   * @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 private method for registering an interface
+   */
+  function _registerInterface(bytes4 _interfaceId)
+    internal
+  {
+    require(_interfaceId != 0xffffffff);
+    supportedInterfaces[_interfaceId] = true;
+  }
+}

contracts/lifecycle/Destructible.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 
 import "../ownership/Ownable.sol";
@@ -9,17 +9,14 @@ import "../ownership/Ownable.sol";
  * @dev Base contract that can be destroyed by owner. All funds in contract will be sent to the owner.
  */
 contract Destructible is Ownable {
-
-  function Destructible() public payable { }
-
   /**
    * @dev Transfers the current balance to the owner and terminates the contract.
    */
-  function destroy() onlyOwner public {
+  function destroy() public onlyOwner {
     selfdestruct(owner);
   }
 
-  function destroyAndSend(address _recipient) onlyOwner public {
+  function destroyAndSend(address _recipient) public onlyOwner {
     selfdestruct(_recipient);
   }
 }

contracts/lifecycle/Migrations.sol

@@ -1,21 +0,0 @@
-pragma solidity ^0.4.18;
-
-import "../ownership/Ownable.sol";
-
-
-/**
- * @title Migrations
- * @dev This is a truffle contract, needed for truffle integration, not meant for use by Zeppelin users.
- */
-contract Migrations is Ownable {
-  uint256 public lastCompletedMigration;
-
-  function setCompleted(uint256 completed) onlyOwner public {
-    lastCompletedMigration = completed;
-  }
-
-  function upgrade(address newAddress) onlyOwner public {
-    Migrations upgraded = Migrations(newAddress);
-    upgraded.setCompleted(lastCompletedMigration);
-  }
-}

contracts/lifecycle/Pausable.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 
 import "../ownership/Ownable.sol";
@@ -34,16 +34,16 @@ contract Pausable is Ownable {
   /**
    * @dev called by the owner to pause, triggers stopped state
    */
-  function pause() onlyOwner whenNotPaused public {
+  function pause() public onlyOwner whenNotPaused {
     paused = true;
-    Pause();
+    emit Pause();
   }
 
   /**
    * @dev called by the owner to unpause, returns to normal state
    */
-  function unpause() onlyOwner whenPaused public {
+  function unpause() public onlyOwner whenPaused {
     paused = false;
-    Unpause();
+    emit Unpause();
   }
 }

contracts/lifecycle/TokenDestructible.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "../ownership/Ownable.sol";
 import "../token/ERC20/ERC20Basic.sol";
@@ -12,20 +12,20 @@ import "../token/ERC20/ERC20Basic.sol";
  */
 contract TokenDestructible is Ownable {
 
-  function TokenDestructible() public payable { }
+  constructor() public payable { }
 
   /**
    * @notice Terminate contract and refund to owner
-   * @param tokens List of addresses of ERC20 or ERC20Basic token contracts to
+   * @param _tokens List of addresses of ERC20 or ERC20Basic token contracts to
    refund.
    * @notice The called token contracts could try to re-enter this contract. Only
    supply token contracts you trust.
    */
-  function destroy(address[] tokens) onlyOwner public {
+  function destroy(address[] _tokens) public onlyOwner {
 
     // Transfer tokens to owner
-    for (uint256 i = 0; i < tokens.length; i++) {
-      ERC20Basic token = ERC20Basic(tokens[i]);
+    for (uint256 i = 0; i < _tokens.length; i++) {
+      ERC20Basic token = ERC20Basic(_tokens[i]);
       uint256 balance = token.balanceOf(this);
       token.transfer(owner, balance);
     }

contracts/math/Math.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 
 /**
@@ -6,19 +6,19 @@ pragma solidity ^0.4.18;
  * @dev Assorted math operations
  */
 library Math {
-  function max64(uint64 a, uint64 b) internal pure returns (uint64) {
-    return a >= b ? a : b;
+  function max64(uint64 _a, uint64 _b) internal pure returns (uint64) {
+    return _a >= _b ? _a : _b;
   }
 
-  function min64(uint64 a, uint64 b) internal pure returns (uint64) {
-    return a < b ? a : b;
+  function min64(uint64 _a, uint64 _b) internal pure returns (uint64) {
+    return _a < _b ? _a : _b;
   }
 
-  function max256(uint256 a, uint256 b) internal pure returns (uint256) {
-    return a >= b ? a : b;
+  function max256(uint256 _a, uint256 _b) internal pure returns (uint256) {
+    return _a >= _b ? _a : _b;
   }
 
-  function min256(uint256 a, uint256 b) internal pure returns (uint256) {
-    return a < b ? a : b;
+  function min256(uint256 _a, uint256 _b) internal pure returns (uint256) {
+    return _a < _b ? _a : _b;
   }
 }

contracts/math/SafeMath.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 
 /**
@@ -10,39 +10,43 @@ library SafeMath {
   /**
   * @dev Multiplies two numbers, throws on overflow.
   */
-  function mul(uint256 a, uint256 b) internal pure returns (uint256) {
-    if (a == 0) {
+  function mul(uint256 _a, uint256 _b) internal pure returns (uint256 c) {
+    // Gas optimization: this is cheaper than asserting '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;
-    assert(c / a == b);
+
+    c = _a * _b;
+    assert(c / _a == _b);
     return c;
   }
 
   /**
   * @dev Integer division of two numbers, truncating the quotient.
   */
-  function div(uint256 a, uint256 b) internal pure returns (uint256) {
-    // assert(b > 0); // Solidity automatically throws when dividing by 0
-    uint256 c = a / b;
-    // assert(a == b * c + a % b); // There is no case in which this doesn't hold
-    return c;
+  function div(uint256 _a, uint256 _b) internal pure returns (uint256) {
+    // assert(_b > 0); // Solidity automatically throws when dividing by 0
+    // uint256 c = _a / _b;
+    // assert(_a == _b * c + _a % _b); // There is no case in which this doesn't hold
+    return _a / _b;
   }
 
   /**
-  * @dev Substracts two numbers, throws on overflow (i.e. if subtrahend is greater than minuend).
+  * @dev Subtracts two numbers, throws on overflow (i.e. if subtrahend is greater than minuend).
   */
-  function sub(uint256 a, uint256 b) internal pure returns (uint256) {
-    assert(b <= a);
-    return a - b;
+  function sub(uint256 _a, uint256 _b) internal pure returns (uint256) {
+    assert(_b <= _a);
+    return _a - _b;
   }
 
   /**
   * @dev Adds two numbers, throws on overflow.
   */
-  function add(uint256 a, uint256 b) internal pure returns (uint256) {
-    uint256 c = a + b;
-    assert(c >= a);
+  function add(uint256 _a, uint256 _b) internal pure returns (uint256 c) {
+    c = _a + _b;
+    assert(c >= _a);
     return c;
   }
 }

contracts/mocks/AllowanceCrowdsaleImpl.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "../token/ERC20/ERC20.sol";
 import "../crowdsale/emission/AllowanceCrowdsale.sol";
@@ -6,12 +6,12 @@ import "../crowdsale/emission/AllowanceCrowdsale.sol";
 
 contract AllowanceCrowdsaleImpl is AllowanceCrowdsale {
 
-  function AllowanceCrowdsaleImpl (
+  constructor (
     uint256 _rate,
     address _wallet,
     ERC20 _token,
     address _tokenWallet
-  ) 
+  )
     public
     Crowdsale(_rate, _wallet, _token)
     AllowanceCrowdsale(_tokenWallet)

contracts/mocks/AutoIncrementingImpl.sol

@@ -0,0 +1,21 @@
+pragma solidity ^0.4.24;
+
+import "../AutoIncrementing.sol";
+
+
+contract AutoIncrementingImpl {
+  using AutoIncrementing for AutoIncrementing.Counter;
+
+  uint256 public theId;
+
+  // use whatever key you want to track your counters
+  mapping(string => AutoIncrementing.Counter) private counters;
+
+  function doThing(string _key)
+    public
+    returns (uint256)
+  {
+    theId = counters[_key].nextId();
+    return theId;
+  }
+}

contracts/mocks/BasicTokenMock.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 
 import "../token/ERC20/BasicToken.sol";
@@ -7,9 +7,9 @@ import "../token/ERC20/BasicToken.sol";
 // mock class using BasicToken
 contract BasicTokenMock is BasicToken {
 
-  function BasicTokenMock(address initialAccount, uint256 initialBalance) public {
-    balances[initialAccount] = initialBalance;
-    totalSupply_ = initialBalance;
+  constructor(address _initialAccount, uint256 _initialBalance) public {
+    balances[_initialAccount] = _initialBalance;
+    totalSupply_ = _initialBalance;
   }
 
 }

contracts/mocks/BouncerMock.sol

@@ -0,0 +1,66 @@
+pragma solidity ^0.4.24;
+
+import "../access/SignatureBouncer.sol";
+
+
+contract SignatureBouncerMock is SignatureBouncer {
+  function checkValidSignature(address _address, bytes _sig)
+    public
+    view
+    returns (bool)
+  {
+    return isValidSignature(_address, _sig);
+  }
+
+  function onlyWithValidSignature(bytes _sig)
+    public
+    onlyValidSignature(_sig)
+    view
+  {
+
+  }
+
+  function checkValidSignatureAndMethod(address _address, bytes _sig)
+    public
+    view
+    returns (bool)
+  {
+    return isValidSignatureAndMethod(_address, _sig);
+  }
+
+  function onlyWithValidSignatureAndMethod(bytes _sig)
+    public
+    onlyValidSignatureAndMethod(_sig)
+    view
+  {
+
+  }
+
+  function checkValidSignatureAndData(
+    address _address,
+    bytes,
+    uint,
+    bytes _sig
+  )
+    public
+    view
+    returns (bool)
+  {
+    return isValidSignatureAndData(_address, _sig);
+  }
+
+  function onlyWithValidSignatureAndData(uint, bytes _sig)
+    public
+    onlyValidSignatureAndData(_sig)
+    view
+  {
+
+  }
+
+  function theWrongMethod(bytes)
+    public
+    pure
+  {
+
+  }
+}

contracts/mocks/BurnableTokenMock.sol

@@ -1,13 +1,13 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "../token/ERC20/BurnableToken.sol";
 
 
 contract BurnableTokenMock is BurnableToken {
 
-  function BurnableTokenMock(address initialAccount, uint initialBalance) public {
-    balances[initialAccount] = initialBalance;
-    totalSupply_ = initialBalance;
+  constructor(address _initialAccount, uint _initialBalance) public {
+    balances[_initialAccount] = _initialBalance;
+    totalSupply_ = _initialBalance;
   }
 
 }

contracts/mocks/CappedCrowdsaleImpl.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "../token/ERC20/ERC20.sol";
 import "../crowdsale/validation/CappedCrowdsale.sol";
@@ -6,12 +6,12 @@ import "../crowdsale/validation/CappedCrowdsale.sol";
 
 contract CappedCrowdsaleImpl is CappedCrowdsale {
 
-  function CappedCrowdsaleImpl (
+  constructor (
     uint256 _rate,
     address _wallet,
     ERC20 _token,
     uint256 _cap
-  ) 
+  )
     public
     Crowdsale(_rate, _wallet, _token)
     CappedCrowdsale(_cap)

contracts/mocks/ConditionalEscrowMock.sol

@@ -0,0 +1,18 @@
+pragma solidity ^0.4.24;
+
+
+import "../payment/ConditionalEscrow.sol";
+
+
+// mock class using ConditionalEscrow
+contract ConditionalEscrowMock is ConditionalEscrow {
+  mapping(address => bool) public allowed;
+
+  function setAllowed(address _payee, bool _allowed) public {
+    allowed[_payee] = _allowed;
+  }
+
+  function withdrawalAllowed(address _payee) public view returns (bool) {
+    return allowed[_payee];
+  }
+}

contracts/mocks/DayLimitMock.sol

@@ -1,25 +0,0 @@
-pragma solidity ^0.4.18;
-
-import "../../contracts/DayLimit.sol";
-
-
-contract DayLimitMock is DayLimit {
-  uint256 public totalSpending;
-
-  function DayLimitMock(uint256 _value) public DayLimit(_value) {
-    totalSpending = 0;
-  }
-
-  function attemptSpend(uint256 _value) external limitedDaily(_value) {
-    totalSpending += _value;
-  }
-
-  function setDailyLimit(uint256 _newLimit) external {
-    _setDailyLimit(_newLimit);
-  }
-
-  function resetSpentToday() external {
-    _resetSpentToday();
-  }
-
-}

contracts/mocks/DestructibleMock.sol

@@ -0,0 +1,8 @@
+pragma solidity ^0.4.24;
+
+import "../lifecycle/Destructible.sol";
+
+
+contract DestructibleMock is Destructible {
+  function() public payable {}
+}

contracts/mocks/DetailedERC20Mock.sol

@@ -1,9 +1,16 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "../token/ERC20/StandardToken.sol";
 import "../token/ERC20/DetailedERC20.sol";
 
 
 contract DetailedERC20Mock is StandardToken, DetailedERC20 {
-  function DetailedERC20Mock(string _name, string _symbol, uint8 _decimals) DetailedERC20(_name, _symbol, _decimals) public {}
+  constructor(
+    string _name,
+    string _symbol,
+    uint8 _decimals
+  )
+    DetailedERC20(_name, _symbol, _decimals)
+    public
+  {}
 }

contracts/mocks/ECRecoveryMock.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 
 import "../ECRecovery.sol";
@@ -7,10 +7,19 @@ import "../ECRecovery.sol";
 contract ECRecoveryMock {
   using ECRecovery for bytes32;
 
-  address public addrRecovered;
-
-  function recover(bytes32 hash, bytes sig) public returns (address) {
-    addrRecovered = hash.recover(sig);
+  function recover(bytes32 _hash, bytes _sig)
+    public
+    pure
+    returns (address)
+  {
+    return _hash.recover(_sig);
   }
 
+  function toEthSignedMessageHash(bytes32 _hash)
+    public
+    pure
+    returns (bytes32)
+  {
+    return _hash.toEthSignedMessageHash();
+  }
 }

contracts/mocks/ERC20WithMetadataMock.sol

@@ -0,0 +1,12 @@
+pragma solidity ^0.4.21;
+
+import "../token/ERC20/StandardToken.sol";
+import "../proposals/ERC1046/TokenMetadata.sol";
+
+
+contract ERC20WithMetadataMock is StandardToken, ERC20WithMetadata {
+  constructor(string _tokenURI) public
+    ERC20WithMetadata(_tokenURI)
+  {
+  }
+}

contracts/mocks/ERC223TokenMock.sol

@@ -1,16 +1,18 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "../token/ERC20/BasicToken.sol";
 
+
 contract ERC223ContractInterface {
   function tokenFallback(address _from, uint256 _value, bytes _data) external;
 }
 
+
 contract ERC223TokenMock is BasicToken {
 
-  function ERC223TokenMock(address initialAccount, uint256 initialBalance) public {
-    balances[initialAccount] = initialBalance;
-    totalSupply_ = initialBalance;
+  constructor(address _initialAccount, uint256 _initialBalance) public {
+    balances[_initialAccount] = _initialBalance;
+    totalSupply_ = _initialBalance;
   }
 
   // ERC223 compatible transfer function (except the name)
@@ -18,11 +20,12 @@ contract ERC223TokenMock is BasicToken {
     returns (bool success)
   {
     transfer(_to, _value);
-    bool is_contract = false;
+    bool isContract = false;
+    // solium-disable-next-line security/no-inline-assembly
     assembly {
-      is_contract := not(iszero(extcodesize(_to)))
+      isContract := not(iszero(extcodesize(_to)))
     }
-    if (is_contract) {
+    if (isContract) {
       ERC223ContractInterface receiver = ERC223ContractInterface(_to);
       receiver.tokenFallback(msg.sender, _value, _data);
     }

contracts/mocks/ERC721BasicTokenMock.sol

@@ -0,0 +1,18 @@
+pragma solidity ^0.4.24;
+
+import "../token/ERC721/ERC721BasicToken.sol";
+
+
+/**
+ * @title ERC721BasicTokenMock
+ * This mock just provides a public mint and burn functions for testing purposes
+ */
+contract ERC721BasicTokenMock is ERC721BasicToken {
+  function mint(address _to, uint256 _tokenId) public {
+    super._mint(_to, _tokenId);
+  }
+
+  function burn(uint256 _tokenId) public {
+    super._burn(ownerOf(_tokenId), _tokenId);
+  }
+}

contracts/mocks/ERC721ReceiverMock.sol

@@ -0,0 +1,42 @@
+pragma solidity ^0.4.24;
+
+import "../token/ERC721/ERC721Receiver.sol";
+
+
+contract ERC721ReceiverMock is ERC721Receiver {
+  bytes4 retval;
+  bool reverts;
+
+  event Received(
+    address _operator,
+    address _from,
+    uint256 _tokenId,
+    bytes _data,
+    uint256 _gas
+  );
+
+  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;
+  }
+}

contracts/mocks/ERC721TokenMock.sol

@@ -1,19 +1,31 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "../token/ERC721/ERC721Token.sol";
 
+
 /**
  * @title ERC721TokenMock
- * This mock just provides a public mint and burn functions for testing purposes.
+ * This mock just provides a public mint and burn functions for testing purposes,
+ * and a public setter for metadata URI
  */
 contract ERC721TokenMock is ERC721Token {
-  function ERC721TokenMock() ERC721Token() public { }
+  constructor(string name, string symbol) public
+    ERC721Token(name, symbol)
+  { }
 
   function mint(address _to, uint256 _tokenId) public {
     super._mint(_to, _tokenId);
   }
 
   function burn(uint256 _tokenId) public {
-    super._burn(_tokenId);
+    super._burn(ownerOf(_tokenId), _tokenId);
+  }
+
+  function setTokenURI(uint256 _tokenId, string _uri) public {
+    super._setTokenURI(_tokenId, _uri);
+  }
+  
+  function _removeTokenFrom(address _from, uint256 _tokenId) public {
+    super.removeTokenFrom(_from, _tokenId);
   }
 }

contracts/mocks/ERC827TokenMock.sol

@@ -1,15 +0,0 @@
-pragma solidity ^0.4.13;
-
-
-import "../token/ERC827/ERC827Token.sol";
-
-
-// mock class using ERC827 Token
-contract ERC827TokenMock is ERC827Token {
-
-  function ERC827TokenMock(address initialAccount, uint256 initialBalance) public {
-    balances[initialAccount] = initialBalance;
-    totalSupply_ = initialBalance;
-  }
-
-}

contracts/mocks/FinalizableCrowdsaleImpl.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "../token/ERC20/MintableToken.sol";
 import "../crowdsale/distribution/FinalizableCrowdsale.sol";
@@ -6,13 +6,13 @@ import "../crowdsale/distribution/FinalizableCrowdsale.sol";
 
 contract FinalizableCrowdsaleImpl is FinalizableCrowdsale {
 
-  function FinalizableCrowdsaleImpl (
+  constructor (
     uint256 _openingTime,
     uint256 _closingTime,
     uint256 _rate,
     address _wallet,
     MintableToken _token
-  ) 
+  )
     public
     Crowdsale(_rate, _wallet, _token)
     TimedCrowdsale(_openingTime, _closingTime)

contracts/mocks/ForceEther.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 
 // @title Force Ether into a contract.
@@ -8,7 +8,7 @@ pragma solidity ^0.4.18;
 // @author Remco Bloemen <remco@neufund.org>
 contract ForceEther {
 
-  function ForceEther() public payable { }
+  constructor() public payable { }
 
   function destroyAndSend(address _recipient) public {
     selfdestruct(_recipient);

contracts/mocks/HasNoEtherTest.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "../../contracts/ownership/HasNoEther.sol";
 
@@ -6,7 +6,7 @@ import "../../contracts/ownership/HasNoEther.sol";
 contract HasNoEtherTest is HasNoEther {
 
   // Constructor with explicit payable — should still fail
-  function HasNoEtherTest() public payable {
+  constructor() public payable {
   }
 
 }

contracts/mocks/IncreasingPriceCrowdsaleImpl.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "../crowdsale/price/IncreasingPriceCrowdsale.sol";
 import "../math/SafeMath.sol";
@@ -6,14 +6,14 @@ import "../math/SafeMath.sol";
 
 contract IncreasingPriceCrowdsaleImpl is IncreasingPriceCrowdsale {
 
-  function IncreasingPriceCrowdsaleImpl (
+  constructor (
     uint256 _openingTime,
     uint256 _closingTime,
     address _wallet,
     ERC20 _token,
     uint256 _initialRate,
     uint256 _finalRate
-  ) 
+  )
     public
     Crowdsale(_initialRate, _wallet, _token)
     TimedCrowdsale(_openingTime, _closingTime)

contracts/mocks/IndividuallyCappedCrowdsaleImpl.sol

@@ -1,16 +1,16 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "../token/ERC20/ERC20.sol";
 import "../crowdsale/validation/IndividuallyCappedCrowdsale.sol";
 
 
 contract IndividuallyCappedCrowdsaleImpl is IndividuallyCappedCrowdsale {
-  
-  function IndividuallyCappedCrowdsaleImpl (
+
+  constructor (
     uint256 _rate,
     address _wallet,
     ERC20 _token
-  ) 
+  )
     public
     Crowdsale(_rate, _wallet, _token)
   {

contracts/mocks/InsecureTargetBounty.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import {Bounty, Target} from "../../contracts/Bounty.sol";
 

contracts/mocks/LimitBalanceMock.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 
 import "../LimitBalance.sol";

contracts/mocks/MathMock.sol

@@ -0,0 +1,26 @@
+pragma solidity ^0.4.24;
+
+
+import "../../contracts/math/Math.sol";
+
+
+contract MathMock {
+  uint64 public result64;
+  uint256 public result256;
+
+  function max64(uint64 _a, uint64 _b) public {
+    result64 = Math.max64(_a, _b);
+  }
+
+  function min64(uint64 _a, uint64 _b) public {
+    result64 = Math.min64(_a, _b);
+  }
+
+  function max256(uint256 _a, uint256 _b) public {
+    result256 = Math.max256(_a, _b);
+  }
+
+  function min256(uint256 _a, uint256 _b) public {
+    result256 = Math.min256(_a, _b);
+  }
+}

contracts/mocks/MerkleProofWrapper.sol

@@ -0,0 +1,19 @@
+pragma solidity ^0.4.24;
+
+import { MerkleProof } from "../MerkleProof.sol";
+
+
+contract MerkleProofWrapper {
+
+  function verifyProof(
+    bytes32[] _proof,
+    bytes32 _root,
+    bytes32 _leaf
+  )
+    public
+    pure
+    returns (bool)
+  {
+    return MerkleProof.verifyProof(_proof, _root, _leaf);
+  }
+}

contracts/mocks/MessageHelper.sol

@@ -1,11 +1,37 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.24;
+
 
 contract MessageHelper {
 
   event Show(bytes32 b32, uint256 number, string text);
+  event Buy(bytes32 b32, uint256 number, string text, uint256 value);
 
-  function showMessage( bytes32 message, uint256 number, string text ) public returns (bool) {
-    Show(message, number, text);
+  function showMessage(
+    bytes32 _message,
+    uint256 _number,
+    string _text
+  )
+    public
+    returns (bool)
+  {
+    emit Show(_message, _number, _text);
+    return true;
+  }
+
+  function buyMessage(
+    bytes32 _message,
+    uint256 _number,
+    string _text
+  )
+    public
+    payable
+    returns (bool)
+  {
+    emit Buy(
+      _message,
+      _number,
+      _text,
+      msg.value);
     return true;
   }
 
@@ -13,8 +39,9 @@ contract MessageHelper {
     require(false);
   }
 
-  function call(address to, bytes data) public returns (bool) {
-    if (to.call(data))
+  function call(address _to, bytes _data) public returns (bool) {
+    // solium-disable-next-line security/no-low-level-calls
+    if (_to.call(_data))
       return true;
     else
       return false;

contracts/mocks/MintedCrowdsaleImpl.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "../token/ERC20/MintableToken.sol";
 import "../crowdsale/emission/MintedCrowdsale.sol";
@@ -6,11 +6,11 @@ import "../crowdsale/emission/MintedCrowdsale.sol";
 
 contract MintedCrowdsaleImpl is MintedCrowdsale {
 
-  function MintedCrowdsaleImpl (
+  constructor (
     uint256 _rate,
     address _wallet,
     MintableToken _token
-  ) 
+  )
     public
     Crowdsale(_rate, _wallet, _token)
   {

contracts/mocks/PausableMock.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 
 import "../lifecycle/Pausable.sol";
@@ -9,7 +9,7 @@ contract PausableMock is Pausable {
   bool public drasticMeasureTaken;
   uint256 public count;
 
-  function PausableMock() public {
+  constructor() public {
     drasticMeasureTaken = false;
     count = 0;
   }

contracts/mocks/PausableTokenMock.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "../token/ERC20/PausableToken.sol";
 
@@ -6,8 +6,8 @@ import "../token/ERC20/PausableToken.sol";
 // mock class using PausableToken
 contract PausableTokenMock is PausableToken {
 
-  function PausableTokenMock(address initialAccount, uint initialBalance) public {
-    balances[initialAccount] = initialBalance;
+  constructor(address _initialAccount, uint _initialBalance) public {
+    balances[_initialAccount] = _initialBalance;
   }
 
 }

contracts/mocks/PostDeliveryCrowdsaleImpl.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "../token/ERC20/ERC20.sol";
 import "../crowdsale/distribution/PostDeliveryCrowdsale.sol";
@@ -6,13 +6,13 @@ import "../crowdsale/distribution/PostDeliveryCrowdsale.sol";
 
 contract PostDeliveryCrowdsaleImpl is PostDeliveryCrowdsale {
 
-  function PostDeliveryCrowdsaleImpl (
+  constructor (
     uint256 _openingTime,
     uint256 _closingTime,
     uint256 _rate,
     address _wallet,
     ERC20 _token
-  ) 
+  )
     public
     TimedCrowdsale(_openingTime, _closingTime)
     Crowdsale(_rate, _wallet, _token)

contracts/mocks/PullPaymentMock.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 
 import "../payment/PullPayment.sol";
@@ -7,11 +7,11 @@ import "../payment/PullPayment.sol";
 // mock class using PullPayment
 contract PullPaymentMock is PullPayment {
 
-  function PullPaymentMock() public payable { }
+  constructor() public payable { }
 
-  // test helper function to call asyncSend
-  function callSend(address dest, uint256 amount) public {
-    asyncSend(dest, amount);
+  // test helper function to call asyncTransfer
+  function callTransfer(address _dest, uint256 _amount) public {
+    asyncTransfer(_dest, _amount);
   }
 
 }

contracts/mocks/RBACCappedTokenMock.sol

@@ -0,0 +1,12 @@
+pragma solidity ^0.4.24;
+
+import "../token/ERC20/RBACMintableToken.sol";
+import "../token/ERC20/CappedToken.sol";
+
+
+contract RBACCappedTokenMock is CappedToken, RBACMintableToken {
+  constructor(uint256 _cap)
+    CappedToken(_cap)
+    public
+  {}
+}

contracts/mocks/RBACMock.sol

@@ -1,9 +1,9 @@
-pragma solidity ^0.4.8;
+pragma solidity ^0.4.24;
 
-import "../ownership/rbac/RBAC.sol";
+import "../examples/RBACWithAdmin.sol";
 
 
-contract RBACMock is RBAC {
+contract RBACMock is RBACWithAdmin {
 
   string constant ROLE_ADVISOR = "advisor";
 
@@ -16,7 +16,7 @@ contract RBACMock is RBAC {
     _;
   }
 
-  function RBACMock(address[] _advisors)
+  constructor(address[] _advisors)
     public
   {
     addRole(msg.sender, ROLE_ADVISOR);
@@ -27,37 +27,37 @@ contract RBACMock is RBAC {
   }
 
   function onlyAdminsCanDoThis()
+    external
     onlyAdmin
     view
-    external
   {
   }
 
   function onlyAdvisorsCanDoThis()
+    external
     onlyRole(ROLE_ADVISOR)
     view
-    external
   {
   }
 
   function eitherAdminOrAdvisorCanDoThis()
+    external
     onlyAdminOrAdvisor
     view
-    external
   {
   }
 
   function nobodyCanDoThis()
+    external
     onlyRole("unknown")
     view
-    external
   {
   }
 
   // admins can remove advisor's role
   function removeAdvisor(address _addr)
-    onlyAdmin
     public
+    onlyAdmin
   {
     // revert if the user isn't an advisor
     //  (perhaps you want to soft-fail here instead?)

contracts/mocks/ReentrancyAttack.sol

@@ -1,10 +1,11 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 
 contract ReentrancyAttack {
 
-  function callSender(bytes4 data) public {
-    require(msg.sender.call(data));
+  function callSender(bytes4 _data) public {
+    // solium-disable-next-line security/no-low-level-calls
+    require(msg.sender.call(abi.encodeWithSelector(_data)));
   }
 
 }

contracts/mocks/ReentrancyMock.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "../ReentrancyGuard.sol";
 import "./ReentrancyAttack.sol";
@@ -8,7 +8,7 @@ contract ReentrancyMock is ReentrancyGuard {
 
   uint256 public counter;
 
-  function ReentrancyMock() public {
+  constructor() public {
     counter = 0;
   }
 
@@ -16,26 +16,26 @@ contract ReentrancyMock is ReentrancyGuard {
     count();
   }
 
-  function countLocalRecursive(uint256 n) public nonReentrant {
-    if (n > 0) {
+  function countLocalRecursive(uint256 _n) public nonReentrant {
+    if (_n > 0) {
       count();
-      countLocalRecursive(n - 1);
+      countLocalRecursive(_n - 1);
     }
   }
 
-  function countThisRecursive(uint256 n) public nonReentrant {
-    bytes4 func = bytes4(keccak256("countThisRecursive(uint256)"));
-    if (n > 0) {
+  function countThisRecursive(uint256 _n) public nonReentrant {
+    if (_n > 0) {
       count();
-      bool result = this.call(func, n - 1);
+      // solium-disable-next-line security/no-low-level-calls
+      bool result = address(this).call(abi.encodeWithSignature("countThisRecursive(uint256)", _n - 1));
       require(result == true);
     }
   }
 
-  function countAndCall(ReentrancyAttack attacker) public nonReentrant {
+  function countAndCall(ReentrancyAttack _attacker) public nonReentrant {
     count();
     bytes4 func = bytes4(keccak256("callback()"));
-    attacker.callSender(func);
+    _attacker.callSender(func);
   }
 
   function count() private {

contracts/mocks/RefundableCrowdsaleImpl.sol

@@ -1,18 +1,19 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "../token/ERC20/MintableToken.sol";
 import "../crowdsale/distribution/RefundableCrowdsale.sol";
 
+
 contract RefundableCrowdsaleImpl is RefundableCrowdsale {
 
-  function RefundableCrowdsaleImpl (
+  constructor (
     uint256 _openingTime,
     uint256 _closingTime,
     uint256 _rate,
     address _wallet,
     MintableToken _token,
     uint256 _goal
-  ) 
+  )
     public
     Crowdsale(_rate, _wallet, _token)
     TimedCrowdsale(_openingTime, _closingTime)

contracts/mocks/SafeERC20Helper.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "../token/ERC20/ERC20.sol";
 import "../token/ERC20/SafeERC20.sol";
@@ -21,11 +21,11 @@ contract ERC20FailingMock is ERC20 {
     return false;
   }
 
-  function balanceOf(address) public constant returns (uint256) {
+  function balanceOf(address) public view returns (uint256) {
     return 0;
   }
 
-  function allowance(address, address) public constant returns (uint256) {
+  function allowance(address, address) public view returns (uint256) {
     return 0;
   }
 }
@@ -35,7 +35,7 @@ contract ERC20SucceedingMock is ERC20 {
   function totalSupply() public view returns (uint256) {
     return 0;
   }
-  
+
   function transfer(address, uint256) public returns (bool) {
     return true;
   }
@@ -48,11 +48,11 @@ contract ERC20SucceedingMock is ERC20 {
     return true;
   }
 
-  function balanceOf(address) public constant returns (uint256) {
+  function balanceOf(address) public view returns (uint256) {
     return 0;
   }
 
-  function allowance(address, address) public constant returns (uint256) {
+  function allowance(address, address) public view returns (uint256) {
     return 0;
   }
 }
@@ -64,32 +64,32 @@ contract SafeERC20Helper {
   ERC20 failing;
   ERC20 succeeding;
 
-  function SafeERC20Helper() public {
+  constructor() public {
     failing = new ERC20FailingMock();
     succeeding = new ERC20SucceedingMock();
   }
 
   function doFailingTransfer() public {
-    failing.safeTransfer(0, 0);
+    failing.safeTransfer(address(0), 0);
   }
 
   function doFailingTransferFrom() public {
-    failing.safeTransferFrom(0, 0, 0);
+    failing.safeTransferFrom(address(0), address(0), 0);
   }
 
   function doFailingApprove() public {
-    failing.safeApprove(0, 0);
+    failing.safeApprove(address(0), 0);
   }
 
   function doSucceedingTransfer() public {
-    succeeding.safeTransfer(0, 0);
+    succeeding.safeTransfer(address(0), 0);
   }
 
   function doSucceedingTransferFrom() public {
-    succeeding.safeTransferFrom(0, 0, 0);
+    succeeding.safeTransferFrom(address(0), address(0), 0);
   }
 
   function doSucceedingApprove() public {
-    succeeding.safeApprove(0, 0);
+    succeeding.safeApprove(address(0), 0);
   }
 }

contracts/mocks/SafeMathMock.sol

@@ -1,21 +1,24 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 
 import "../math/SafeMath.sol";
 
 
 contract SafeMathMock {
-  uint256 public result;
 
-  function multiply(uint256 a, uint256 b) public {
-    result = SafeMath.mul(a, b);
+  function mul(uint256 _a, uint256 _b) public pure returns (uint256) {
+    return SafeMath.mul(_a, _b);
   }
 
-  function subtract(uint256 a, uint256 b) public {
-    result = SafeMath.sub(a, b);
+  function div(uint256 _a, uint256 _b) public pure returns (uint256) {
+    return SafeMath.div(_a, _b);
   }
 
-  function add(uint256 a, uint256 b) public {
-    result = SafeMath.add(a, b);
+  function sub(uint256 _a, uint256 _b) public pure returns (uint256) {
+    return SafeMath.sub(_a, _b);
+  }
+
+  function add(uint256 _a, uint256 _b) public pure returns (uint256) {
+    return SafeMath.add(_a, _b);
   }
 }

contracts/mocks/SecureTargetBounty.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import {Bounty, Target} from "../../contracts/Bounty.sol";
 

contracts/mocks/StandardBurnableTokenMock.sol

@@ -0,0 +1,13 @@
+pragma solidity ^0.4.24;
+
+import "../token/ERC20/StandardBurnableToken.sol";
+
+
+contract StandardBurnableTokenMock is StandardBurnableToken {
+
+  constructor(address _initialAccount, uint _initialBalance) public {
+    balances[_initialAccount] = _initialBalance;
+    totalSupply_ = _initialBalance;
+  }
+
+}

contracts/mocks/StandardTokenMock.sol

@@ -1,13 +1,14 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "../token/ERC20/StandardToken.sol";
 
+
 // mock class using StandardToken
 contract StandardTokenMock is StandardToken {
 
-  function StandardTokenMock(address initialAccount, uint256 initialBalance) public {
-    balances[initialAccount] = initialBalance;
-    totalSupply_ = initialBalance;
+  constructor(address _initialAccount, uint256 _initialBalance) public {
+    balances[_initialAccount] = _initialBalance;
+    totalSupply_ = _initialBalance;
   }
 
 }

contracts/mocks/SupportsInterfaceWithLookupMock.sol

@@ -0,0 +1,12 @@
+pragma solidity ^0.4.24;
+
+import "../introspection/SupportsInterfaceWithLookup.sol";
+
+
+contract SupportsInterfaceWithLookupMock is SupportsInterfaceWithLookup {
+  function registerInterface(bytes4 _interfaceId)
+    public
+  {
+    _registerInterface(_interfaceId);
+  }
+}

contracts/mocks/TimedCrowdsaleImpl.sol

@@ -1,17 +1,18 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "../token/ERC20/ERC20.sol";
 import "../crowdsale/validation/TimedCrowdsale.sol";
 
+
 contract TimedCrowdsaleImpl is TimedCrowdsale {
 
-  function TimedCrowdsaleImpl (
+  constructor (
     uint256 _openingTime,
     uint256 _closingTime,
     uint256 _rate,
     address _wallet,
     ERC20 _token
-  ) 
+  )
     public
     Crowdsale(_rate, _wallet, _token)
     TimedCrowdsale(_openingTime, _closingTime)

contracts/mocks/WhitelistMock.sol

@@ -0,0 +1,14 @@
+pragma solidity ^0.4.24;
+
+import "../access/Whitelist.sol";
+
+
+contract WhitelistMock is Whitelist {
+
+  function onlyWhitelistedCanDoThis()
+    external
+    onlyIfWhitelisted(msg.sender)
+    view
+  {
+  }
+}

contracts/mocks/WhitelistedCrowdsaleImpl.sol

@@ -1,19 +1,19 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "../token/ERC20/ERC20.sol";
 import "../crowdsale/validation/WhitelistedCrowdsale.sol";
+import "../crowdsale/Crowdsale.sol";
 
 
-contract WhitelistedCrowdsaleImpl is WhitelistedCrowdsale {
+contract WhitelistedCrowdsaleImpl is Crowdsale, WhitelistedCrowdsale {
 
-  function WhitelistedCrowdsaleImpl (
+  constructor (
     uint256 _rate,
     address _wallet,
     ERC20 _token
-  ) 
-    public
+  )
     Crowdsale(_rate, _wallet, _token)
+    public
   {
   }
-
 }

contracts/ownership/CanReclaimToken.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "./Ownable.sol";
 import "../token/ERC20/ERC20Basic.sol";
@@ -16,11 +16,11 @@ contract CanReclaimToken is Ownable {
 
   /**
    * @dev Reclaim all ERC20Basic compatible tokens
-   * @param token ERC20Basic The address of the token contract
+   * @param _token ERC20Basic The address of the token contract
    */
-  function reclaimToken(ERC20Basic token) external onlyOwner {
-    uint256 balance = token.balanceOf(this);
-    token.safeTransfer(owner, balance);
+  function reclaimToken(ERC20Basic _token) external onlyOwner {
+    uint256 balance = _token.balanceOf(this);
+    _token.safeTransfer(owner, balance);
   }
 
 }

contracts/ownership/Claimable.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 
 import "./Ownable.sol";
@@ -24,15 +24,15 @@ contract Claimable is Ownable {
    * @dev Allows the current owner to set the pendingOwner address.
    * @param newOwner The address to transfer ownership to.
    */
-  function transferOwnership(address newOwner) onlyOwner public {
+  function transferOwnership(address newOwner) public onlyOwner {
     pendingOwner = newOwner;
   }
 
   /**
    * @dev Allows the pendingOwner address to finalize the transfer.
    */
-  function claimOwnership() onlyPendingOwner public {
-    OwnershipTransferred(owner, pendingOwner);
+  function claimOwnership() public onlyPendingOwner {
+    emit OwnershipTransferred(owner, pendingOwner);
     owner = pendingOwner;
     pendingOwner = address(0);
   }

contracts/ownership/Contactable.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "./Ownable.sol";
 
@@ -14,9 +14,9 @@ contract Contactable is Ownable {
 
   /**
     * @dev Allows the owner to set a string with their contact information.
-    * @param info The contact information to attach to the contract.
+    * @param _info The contact information to attach to the contract.
     */
-  function setContactInformation(string info) onlyOwner public {
-    contactInformation = info;
+  function setContactInformation(string _info) public onlyOwner {
+    contactInformation = _info;
   }
 }

contracts/ownership/DelayedClaimable.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "./Claimable.sol";
 
@@ -19,7 +19,7 @@ contract DelayedClaimable is Claimable {
    * @param _start The earliest time ownership can be claimed.
    * @param _end The latest time ownership can be claimed.
    */
-  function setLimits(uint256 _start, uint256 _end) onlyOwner public {
+  function setLimits(uint256 _start, uint256 _end) public onlyOwner {
     require(_start <= _end);
     end = _end;
     start = _start;
@@ -29,9 +29,9 @@ contract DelayedClaimable is Claimable {
    * @dev Allows the pendingOwner address to finalize the transfer, as long as it is called within
    * the specified start and end time.
    */
-  function claimOwnership() onlyPendingOwner public {
+  function claimOwnership() public onlyPendingOwner {
     require((block.number <= end) && (block.number >= start));
-    OwnershipTransferred(owner, pendingOwner);
+    emit OwnershipTransferred(owner, pendingOwner);
     owner = pendingOwner;
     pendingOwner = address(0);
     end = 0;

contracts/ownership/HasNoContracts.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "./Ownable.sol";
 
@@ -13,10 +13,10 @@ contract HasNoContracts is Ownable {
 
   /**
    * @dev Reclaim ownership of Ownable contracts
-   * @param contractAddr The address of the Ownable to be reclaimed.
+   * @param _contractAddr The address of the Ownable to be reclaimed.
    */
-  function reclaimContract(address contractAddr) external onlyOwner {
-    Ownable contractInst = Ownable(contractAddr);
+  function reclaimContract(address _contractAddr) external onlyOwner {
+    Ownable contractInst = Ownable(_contractAddr);
     contractInst.transferOwnership(owner);
   }
 }

contracts/ownership/HasNoEther.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "./Ownable.sol";
 
@@ -7,27 +7,27 @@ import "./Ownable.sol";
  * @title Contracts that should not own Ether
  * @author Remco Bloemen <remco@2π.com>
  * @dev This tries to block incoming ether to prevent accidental loss of Ether. Should Ether end up
- * in the contract, it will allow the owner to reclaim this ether.
- * @notice Ether can still be send to this contract by:
+ * in the contract, it will allow the owner to reclaim this Ether.
+ * @notice Ether can still be sent to this contract by:
  * calling functions labeled `payable`
  * `selfdestruct(contract_address)`
  * mining directly to the contract address
-*/
+ */
 contract HasNoEther is Ownable {
 
   /**
   * @dev Constructor that rejects incoming Ether
-  * @dev The `payable` flag is added so we can access `msg.value` without compiler warning. If we
+  * The `payable` flag is added so we can access `msg.value` without compiler warning. If we
   * leave out payable, then Solidity will allow inheriting contracts to implement a payable
   * constructor. By doing it this way we prevent a payable constructor from working. Alternatively
   * we could use assembly to access msg.value.
   */
-  function HasNoEther() public payable {
+  constructor() public payable {
     require(msg.value == 0);
   }
 
   /**
-   * @dev Disallows direct send by settings a default function without the `payable` flag.
+   * @dev Disallows direct send by setting a default function without the `payable` flag.
    */
   function() external {
   }
@@ -36,6 +36,6 @@ contract HasNoEther is Ownable {
    * @dev Transfer all Ether held by the contract to the owner.
    */
   function reclaimEther() external onlyOwner {
-    assert(owner.send(this.balance));
+    owner.transfer(address(this).balance);
   }
 }