v1.11.0-rc.1

* Added basic Escrow

* PullPayment now uses an Escrow, removing all trust from the contract

* Abstracted the Escrow tests to a behaviour

* Added ConditionalEscrow

* Added RefundableEscrow.

* RefundableCrowdsale now uses a RefundEscrow, removed RefundVault.

* Renaming after code review.

* Added log test helper.

* Now allowing empty deposits and withdrawals.

* Style fixes.

* Minor review comments.

* Add Deposited and Withdrawn events, removed Refunded

* The base Escrow is now Ownable, users of it (owners) must provide methods to access it.

.gitignore

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

.soliumrc.json

@@ -5,7 +5,8 @@
     "quotes": ["error", "double"],
     "no-empty-blocks": "off",
     "indentation": ["error", 2],
-    "arg-overflow": ["warning", 3],
+    "max-len": ["warning", 79],
+    "no-constant": ["error"],
     "security/enforce-explicit-visibility": ["error"],
     "security/no-block-members": ["warning"],
     "security/no-inline-assembly": ["warning"]

CONTRIBUTING.md

@@ -20,13 +20,13 @@ As a contributor, you are expected to fork this repository, work on your own for
 
 ```
 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 `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

README.md

@@ -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
@@ -21,7 +25,20 @@ 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 openzeppelin-solidity
@@ -39,6 +56,15 @@ 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 {
+  ...
+}
+```
 
 ## 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.

contracts/AddressUtils.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 
 /**
@@ -9,7 +9,7 @@ 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.
+   * 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
    */
@@ -21,7 +21,8 @@ library AddressUtils {
     // for more details about how this works.
     // TODO Check this again before the Serenity release, because all addresses will be
     // contracts then.
-    assembly { size := extcodesize(addr) }  // solium-disable-line security/no-inline-assembly
+    // solium-disable-next-line security/no-inline-assembly
+    assembly { size := extcodesize(addr) }
     return size > 0;
   }
 

contracts/Bounty.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 
 import "./payment/PullPayment.sol";
@@ -35,15 +35,15 @@ contract Bounty is PullPayment, Destructible {
   }
 
   /**
-   * @dev Sends the contract funds to the researcher that proved the contract is broken.
+   * @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);
+    require(researcher != address(0));
     // Check Target contract invariants
     require(!target.checkInvariant());
-    asyncSend(researcher, address(this).balance);
+    asyncTransfer(researcher, address(this).balance);
     claimed = true;
   }
 

contracts/DayLimit.sol

@@ -1,75 +0,0 @@
-pragma solidity ^0.4.21;
-
-
-/**
- * @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) {
-    // solium-disable-next-line security/no-block-members
-    return block.timestamp / 1 days;
-  }
-
-  /**
-   * @dev Simple modifier for daily limit.
-   */
-  modifier limitedDaily(uint256 _value) {
-    require(underLimit(_value));
-    _;
-  }
-}

contracts/ECRecovery.sol

@@ -1,14 +1,11 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 
 /**
  * @title Eliptic 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 {
@@ -59,7 +56,7 @@ library ECRecovery {
   /**
    * toEthSignedMessageHash
    * @dev prefix a bytes32 value with "\x19Ethereum Signed Message:"
-   * @dev and hash the result
+   * and hash the result
    */
   function toEthSignedMessageHash(bytes32 hash)
     internal
@@ -69,8 +66,7 @@ library ECRecovery {
     // 32 is the length in bytes of hash,
     // enforced by the type signature above
     return keccak256(
-      "\x19Ethereum Signed Message:\n32",
-      hash
+      abi.encodePacked("\x19Ethereum Signed Message:\n32", hash)
     );
   }
 }

contracts/LimitBalance.sol

@@ -1,11 +1,11 @@
-pragma solidity ^0.4.21;
+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;
   }
 

contracts/MerkleProof.sol

@@ -1,10 +1,10 @@
-pragma solidity ^0.4.21;
+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 {
   /*
@@ -14,7 +14,15 @@ library MerkleProof {
    * @param _root Merkle root
    * @param _leaf Leaf of Merkle tree
    */
-  function verifyProof(bytes32[] _proof, bytes32 _root, bytes32 _leaf) internal pure returns (bool) {
+  function verifyProof(
+    bytes32[] _proof,
+    bytes32 _root,
+    bytes32 _leaf
+  )
+    internal
+    pure
+    returns (bool)
+  {
     bytes32 computedHash = _leaf;
 
     for (uint256 i = 0; i < _proof.length; i++) {
@@ -22,10 +30,10 @@ library MerkleProof {
 
       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

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 
 /**

contracts/access/SignatureBouncer.sol

@@ -1,30 +1,41 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "../ownership/Ownable.sol";
 import "../ownership/rbac/RBAC.sol";
 import "../ECRecovery.sol";
 
+
 /**
  * @title SignatureBouncer
- * @author PhABC and Shrugs
+ * @author PhABC, Shrugs and aflesher
  * @dev Bouncer allows users to submit a signature as a permission to do an action.
- * @dev If the signature is from one of the authorized bouncer addresses, the signature
- * @dev is valid. The owner of the contract adds/removes bouncers.
- * @dev Bouncer addresses can be individual servers signing grants or different
- * @dev users within a decentralized club that have permission to invite other members.
- * @dev
- * @dev This technique is useful for whitelists and airdrops; instead of putting all
- * @dev valid addresses on-chain, simply sign a grant of the form
- * @dev keccak256(`:contractAddress` + `:granteeAddress`) using a valid bouncer address.
- * @dev Then restrict access to your crowdsale/whitelist/airdrop using the
- * @dev `onlyValidSignature` modifier (or implement your own using isValidSignature).
- * @dev
- * @dev See the tests Bouncer.test.js for specific usage examples.
+ * 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 length size) 32 bytes + (signature size 65 bytes padded) 96 bytes
+  uint constant SIGNATURE_SIZE = 128;
 
   /**
    * @dev requires that a valid signature of a bouncer was provided
@@ -35,6 +46,24 @@ contract SignatureBouncer is Ownable, RBAC {
     _;
   }
 
+  /**
+   * @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
    */
@@ -67,14 +96,54 @@ contract SignatureBouncer is Ownable, RBAC {
     returns (bool)
   {
     return isValidDataHash(
-      keccak256(address(this), _address),
+      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
-   * @dev and then recover the signature and check it against the bouncer role
+   * and then recover the signature and check it against the bouncer role
    * @return bool
    */
   function isValidDataHash(bytes32 hash, bytes _sig)

contracts/access/Whitelist.sol

@@ -0,0 +1,91 @@
+pragma solidity ^0.4.24;
+
+
+import "../ownership/Ownable.sol";
+import "../ownership/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)
+    onlyOwner
+    public
+  {
+    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)
+    onlyOwner
+    public
+  {
+    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)
+    onlyOwner
+    public
+  {
+    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)
+    onlyOwner
+    public
+  {
+    for (uint256 i = 0; i < _operators.length; i++) {
+      removeAddressFromWhitelist(_operators[i]);
+    }
+  }
+
+}

contracts/crowdsale/Crowdsale.sol

@@ -1,7 +1,8 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 import "../token/ERC20/ERC20.sol";
 import "../math/SafeMath.sol";
+import "../token/ERC20/SafeERC20.sol";
 
 
 /**
@@ -18,6 +19,7 @@ import "../math/SafeMath.sol";
  */
 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));
@@ -104,7 +114,12 @@ contract Crowdsale {
    * @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);
   }
@@ -114,7 +129,12 @@ 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
   }
 
@@ -123,8 +143,13 @@ 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);
   }
 
   /**
@@ -132,7 +157,12 @@ 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);
   }
 
@@ -141,7 +171,12 @@ 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
   }
 
@@ -150,7 +185,9 @@ 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);
   }
 
@@ -160,4 +197,4 @@ contract Crowdsale {
   function _forwardFunds() internal {
     wallet.transfer(msg.value);
   }
-}
+}

contracts/crowdsale/distribution/FinalizableCrowdsale.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 import "../../math/SafeMath.sol";
 import "../../ownership/Ownable.sol";

contracts/crowdsale/distribution/PostDeliveryCrowdsale.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 import "../validation/TimedCrowdsale.sol";
 import "../../token/ERC20/ERC20.sol";
@@ -30,7 +30,12 @@ contract PostDeliveryCrowdsale is TimedCrowdsale {
    * @param _beneficiary Token purchaser
    * @param _tokenAmount Amount of tokens purchased
    */
-  function _processPurchase(address _beneficiary, uint256 _tokenAmount) internal {
+  function _processPurchase(
+    address _beneficiary,
+    uint256 _tokenAmount
+  )
+    internal
+  {
     balances[_beneficiary] = balances[_beneficiary].add(_tokenAmount);
   }
 

contracts/crowdsale/distribution/RefundableCrowdsale.sol

@@ -1,16 +1,15 @@
-pragma solidity ^0.4.21;
+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;
   }
 
@@ -38,7 +37,7 @@ contract RefundableCrowdsale is FinalizableCrowdsale {
     require(isFinalized);
     require(!goalReached());
 
-    vault.refund(msg.sender);
+    escrow.withdraw(msg.sender);
   }
 
   /**
@@ -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 ^0.4.21;
-
-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;
-    emit Closed();
-    wallet.transfer(address(this).balance);
-  }
-
-  function enableRefunds() onlyOwner public {
-    require(state == State.Active);
-    state = State.Refunding;
-    emit RefundsEnabled();
-  }
-
-  /**
-   * @param investor Investor address
-   */
-  function refund(address investor) public {
-    require(state == State.Refunding);
-    uint256 depositedValue = deposited[investor];
-    deposited[investor] = 0;
-    investor.transfer(depositedValue);
-    emit Refunded(investor, depositedValue);
-  }
-}

contracts/crowdsale/emission/AllowanceCrowdsale.sol

@@ -1,24 +1,25 @@
-pragma solidity ^0.4.21;
+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";
-
-
 /**
  * @title AllowanceCrowdsale
  * @dev Extension of Crowdsale where tokens are held by a wallet, which approves an allowance to the crowdsale.
  */
 contract AllowanceCrowdsale is Crowdsale {
   using SafeMath for uint256;
+  using SafeERC20 for 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 +37,12 @@ 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 ^0.4.21;
+pragma solidity ^0.4.24;
 
 import "../Crowdsale.sol";
 import "../../token/ERC20/MintableToken.sol";
@@ -7,7 +7,7 @@ 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 {
 
@@ -16,7 +16,12 @@ contract MintedCrowdsale is Crowdsale {
    * @param _beneficiary Token purchaser
    * @param _tokenAmount Number of tokens to be minted
    */
-  function _deliverTokens(address _beneficiary, uint256 _tokenAmount) internal {
+  function _deliverTokens(
+    address _beneficiary,
+    uint256 _tokenAmount
+  )
+    internal
+  {
     require(MintableToken(token).mint(_beneficiary, _tokenAmount));
   }
 }

contracts/crowdsale/price/IncreasingPriceCrowdsale.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 import "../validation/TimedCrowdsale.sol";
 import "../../math/SafeMath.sol";
@@ -21,7 +21,7 @@ contract IncreasingPriceCrowdsale is TimedCrowdsale {
    * @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;
@@ -46,7 +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 ^0.4.21;
+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 ^0.4.21;
+pragma solidity ^0.4.24;
 
 import "../../math/SafeMath.sol";
 import "../Crowdsale.sol";
@@ -29,7 +29,13 @@ 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;
     }
@@ -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 ^0.4.21;
+pragma solidity ^0.4.24;
 
 import "../../math/SafeMath.sol";
 import "../Crowdsale.sol";
@@ -28,7 +28,7 @@ contract TimedCrowdsale is Crowdsale {
    * @param _openingTime Crowdsale opening time
    * @param _closingTime Crowdsale closing time
    */
-  function TimedCrowdsale(uint256 _openingTime, uint256 _closingTime) public {
+  constructor(uint256 _openingTime, uint256 _closingTime) public {
     // solium-disable-next-line security/no-block-members
     require(_openingTime >= block.timestamp);
     require(_closingTime >= _openingTime);
@@ -51,7 +51,13 @@ contract TimedCrowdsale is Crowdsale {
    * @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 ^0.4.21;
+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
+  )
+    onlyIfWhitelisted(_beneficiary)
+    internal
+  {
     super._preValidatePurchase(_beneficiary, _weiAmount);
   }
 

contracts/examples/RBACWithAdmin.sol

@@ -1,13 +1,19 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
-import "./RBAC.sol";
+import "../ownership/rbac/RBAC.sol";
 
 
 /**
  * @title RBACWithAdmin
  * @author Matt Condon (@Shrugs)
  * @dev It's recommended that you define constants in the contract,
- * @dev like ROLE_ADMIN below, to avoid typos.
+ * 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 {
   /**
@@ -28,7 +34,7 @@ contract RBACWithAdmin is RBAC {
   /**
    * @dev constructor. Sets msg.sender as admin by default
    */
-  function RBACWithAdmin()
+  constructor()
     public
   {
     addRole(msg.sender, ROLE_ADMIN);

contracts/examples/SampleCrowdsale.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 import "../crowdsale/validation/CappedCrowdsale.sol";
 import "../crowdsale/distribution/RefundableCrowdsale.sol";
@@ -13,7 +13,8 @@ import "../token/ERC20/MintableToken.sol";
  */
 contract SampleCrowdsaleToken is MintableToken {
 
-  string public constant name = "Sample Crowdsale Token"; // solium-disable-line uppercase
+  // solium-disable-next-line uppercase
+  string public constant name = "Sample Crowdsale Token";
   string public constant symbol = "SCT"; // solium-disable-line uppercase
   uint8 public constant decimals = 18; // solium-disable-line uppercase
 
@@ -31,9 +32,14 @@ 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(
+  constructor(
     uint256 _openingTime,
     uint256 _closingTime,
     uint256 _rate,

contracts/examples/SimpleSavingsWallet.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 import "../ownership/Heritable.sol";
 
@@ -19,7 +19,7 @@ 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.
@@ -32,7 +32,7 @@ contract SimpleSavingsWallet is Heritable {
    * @dev wallet can send funds
    */
   function sendTo(address payee, uint256 amount) public onlyOwner {
-    require(payee != 0 && payee != address(this));
+    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 ^0.4.21;
+pragma solidity ^0.4.24;
 
 
 import "../token/ERC20/StandardToken.sol";
@@ -21,10 +21,10 @@ contract SimpleToken is StandardToken {
   /**
    * @dev Constructor that gives msg.sender all of existing tokens.
    */
-  function SimpleToken() public {
+  constructor() public {
     totalSupply_ = INITIAL_SUPPLY;
     balances[msg.sender] = INITIAL_SUPPLY;
-    emit 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 +1,53 @@
+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 ^0.4.21;
+pragma solidity ^0.4.24;
 
 
 import "../ownership/Ownable.sol";
@@ -10,7 +10,7 @@ import "../ownership/Ownable.sol";
  */
 contract Destructible is Ownable {
 
-  function Destructible() public payable { }
+  constructor() public payable { }
 
   /**
    * @dev Transfers the current balance to the owner and terminates the contract.

contracts/lifecycle/Pausable.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 
 import "../ownership/Ownable.sol";

contracts/lifecycle/TokenDestructible.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 import "../ownership/Ownable.sol";
 import "../token/ERC20/ERC20Basic.sol";
@@ -12,7 +12,7 @@ import "../token/ERC20/ERC20Basic.sol";
  */
 contract TokenDestructible is Ownable {
 
-  function TokenDestructible() public payable { }
+  constructor() public payable { }
 
   /**
    * @notice Terminate contract and refund to owner

contracts/math/Math.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 
 /**

contracts/math/SafeMath.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 
 /**
@@ -11,9 +11,13 @@ library SafeMath {
   * @dev Multiplies two numbers, throws on overflow.
   */
   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;
     }
+
     c = a * b;
     assert(c / a == b);
     return c;

contracts/mocks/AllowanceCrowdsaleImpl.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+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/BasicTokenMock.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 
 import "../token/ERC20/BasicToken.sol";
@@ -7,7 +7,7 @@ import "../token/ERC20/BasicToken.sol";
 // mock class using BasicToken
 contract BasicTokenMock is BasicToken {
 
-  function BasicTokenMock(address initialAccount, uint256 initialBalance) public {
+  constructor(address initialAccount, uint256 initialBalance) public {
     balances[initialAccount] = initialBalance;
     totalSupply_ = initialBalance;
   }

contracts/mocks/BouncerMock.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "../access/SignatureBouncer.sol";
 
@@ -19,4 +19,36 @@ contract SignatureBouncerMock is SignatureBouncer {
   {
 
   }
+
+  function checkValidSignatureAndMethod(address _address, bytes _sig)
+    public
+    view
+    returns (bool)
+  {
+    return isValidSignatureAndMethod(_address, _sig);
+  }
+
+  function onlyWithValidSignatureAndMethod(bytes _sig)
+    onlyValidSignatureAndMethod(_sig)
+    public
+    view
+  {
+
+  }
+
+  function checkValidSignatureAndData(address _address, bytes _bytes, uint _val, bytes _sig)
+    public
+    view
+    returns (bool)
+  {
+    return isValidSignatureAndData(_address, _sig);
+  }
+
+  function onlyWithValidSignatureAndData(uint _val, bytes _sig)
+    onlyValidSignatureAndData(_sig)
+    public
+    view
+  {
+
+  }
 }

contracts/mocks/BurnableTokenMock.sol

@@ -1,11 +1,11 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 import "../token/ERC20/BurnableToken.sol";
 
 
 contract BurnableTokenMock is BurnableToken {
 
-  function BurnableTokenMock(address initialAccount, uint initialBalance) public {
+  constructor(address initialAccount, uint initialBalance) public {
     balances[initialAccount] = initialBalance;
     totalSupply_ = initialBalance;
   }

contracts/mocks/CappedCrowdsaleImpl.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+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 ^0.4.21;
-
-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/DetailedERC20Mock.sol

@@ -1,9 +1,16 @@
-pragma solidity ^0.4.21;
+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 ^0.4.21;
+pragma solidity ^0.4.24;
 
 
 import "../ECRecovery.sol";

contracts/mocks/ERC20WithMetadataMock.sol

@@ -0,0 +1,13 @@
+pragma solidity ^0.4.21;
+
+import "../token/ERC20/StandardToken.sol";
+import "../proposals/ERC1046/TokenMetadata.sol";
+
+
+contract ERC20WithMetadataMock is StandardToken, ERC20WithMetadata {
+  function ERC20WithMetadataMock(string _tokenURI)
+    ERC20WithMetadata(_tokenURI)
+    public
+  {
+  }
+}

contracts/mocks/ERC223TokenMock.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 import "../token/ERC20/BasicToken.sol";
 
@@ -10,7 +10,7 @@ contract ERC223ContractInterface {
 
 contract ERC223TokenMock is BasicToken {
 
-  function ERC223TokenMock(address initialAccount, uint256 initialBalance) public {
+  constructor(address initialAccount, uint256 initialBalance) public {
     balances[initialAccount] = initialBalance;
     totalSupply_ = initialBalance;
   }

contracts/mocks/ERC721BasicTokenMock.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 import "../token/ERC721/ERC721BasicToken.sol";
 

contracts/mocks/ERC721ReceiverMock.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 import "../token/ERC721/ERC721Receiver.sol";
 
@@ -7,15 +7,22 @@ contract ERC721ReceiverMock is ERC721Receiver {
   bytes4 retval;
   bool reverts;
 
-  event Received(address _address, uint256 _tokenId, bytes _data, uint256 _gas);
+  event Received(
+    address _operator,
+    address _from,
+    uint256 _tokenId,
+    bytes _data,
+    uint256 _gas
+  );
 
-  function ERC721ReceiverMock(bytes4 _retval, bool _reverts) public {
+  constructor(bytes4 _retval, bool _reverts) public {
     retval = _retval;
     reverts = _reverts;
   }
 
   function onERC721Received(
-    address _address,
+    address _operator,
+    address _from,
     uint256 _tokenId,
     bytes _data
   )
@@ -24,7 +31,8 @@ contract ERC721ReceiverMock is ERC721Receiver {
   {
     require(!reverts);
     emit Received(
-      _address,
+      _operator,
+      _from,
       _tokenId,
       _data,
       gasleft() // msg.gas was deprecated in solidityv0.4.21

contracts/mocks/ERC721TokenMock.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 import "../token/ERC721/ERC721Token.sol";
 
@@ -9,7 +9,7 @@ import "../token/ERC721/ERC721Token.sol";
  * and a public setter for metadata URI
  */
 contract ERC721TokenMock is ERC721Token {
-  function ERC721TokenMock(string name, string symbol) public
+  constructor(string name, string symbol) public
     ERC721Token(name, symbol)
   { }
 

contracts/mocks/ERC827TokenMock.sol

@@ -1,15 +0,0 @@
-pragma solidity ^0.4.21;
-
-
-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 ^0.4.21;
+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 ^0.4.21;
+pragma solidity ^0.4.24;
 
 
 // @title Force Ether into a contract.
@@ -8,7 +8,7 @@ pragma solidity ^0.4.21;
 // @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 ^0.4.21;
+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 ^0.4.21;
+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 ^0.4.21;
+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 ^0.4.21;
+pragma solidity ^0.4.24;
 
 import {Bounty, Target} from "../../contracts/Bounty.sol";
 

contracts/mocks/LimitBalanceMock.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 
 import "../LimitBalance.sol";

contracts/mocks/MathMock.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 
 import "../../contracts/math/Math.sol";

contracts/mocks/MerkleProofWrapper.sol

@@ -1,11 +1,19 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 import { MerkleProof } from "../MerkleProof.sol";
 
 
 contract MerkleProofWrapper {
 
-  function verifyProof(bytes32[] _proof, bytes32 _root, bytes32 _leaf) public pure returns (bool) {
+  function verifyProof(
+    bytes32[] _proof,
+    bytes32 _root,
+    bytes32 _leaf
+  )
+    public
+    pure
+    returns (bool)
+  {
     return MerkleProof.verifyProof(_proof, _root, _leaf);
   }
 }

contracts/mocks/MessageHelper.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 
 contract MessageHelper {
@@ -6,12 +6,27 @@ 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) {
+  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) {
+  function buyMessage(
+    bytes32 message,
+    uint256 number,
+    string text
+  )
+    public
+    payable
+    returns (bool)
+  {
     emit Buy(
       message,
       number,

contracts/mocks/MintedCrowdsaleImpl.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+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 ^0.4.21;
+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 ^0.4.21;
+pragma solidity ^0.4.24;
 
 import "../token/ERC20/PausableToken.sol";
 
@@ -6,7 +6,7 @@ import "../token/ERC20/PausableToken.sol";
 // mock class using PausableToken
 contract PausableTokenMock is PausableToken {
 
-  function PausableTokenMock(address initialAccount, uint initialBalance) public {
+  constructor(address initialAccount, uint initialBalance) public {
     balances[initialAccount] = initialBalance;
   }
 

contracts/mocks/PostDeliveryCrowdsaleImpl.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+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 ^0.4.21;
+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 +1,13 @@
+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

@@ -1,6 +1,6 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
-import "../ownership/rbac/RBACWithAdmin.sol";
+import "../examples/RBACWithAdmin.sol";
 
 
 contract RBACMock is RBACWithAdmin {
@@ -16,7 +16,7 @@ contract RBACMock is RBACWithAdmin {
     _;
   }
 
-  function RBACMock(address[] _advisors)
+  constructor(address[] _advisors)
     public
   {
     addRole(msg.sender, ROLE_ADVISOR);

contracts/mocks/ReentrancyAttack.sol

@@ -1,11 +1,11 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 
 contract ReentrancyAttack {
 
   function callSender(bytes4 data) public {
     // solium-disable-next-line security/no-low-level-calls
-    require(msg.sender.call(data));
+    require(msg.sender.call(abi.encodeWithSelector(data)));
   }
 
 }

contracts/mocks/ReentrancyMock.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+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;
   }
 
@@ -24,11 +24,10 @@ contract ReentrancyMock is ReentrancyGuard {
   }
 
   function countThisRecursive(uint256 n) public nonReentrant {
-    bytes4 func = bytes4(keccak256("countThisRecursive(uint256)"));
     if (n > 0) {
       count();
       // solium-disable-next-line security/no-low-level-calls
-      bool result = address(this).call(func, n - 1);
+      bool result = address(this).call(abi.encodeWithSignature("countThisRecursive(uint256)", n - 1));
       require(result == true);
     }
   }

contracts/mocks/RefundableCrowdsaleImpl.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 import "../token/ERC20/MintableToken.sol";
 import "../crowdsale/distribution/RefundableCrowdsale.sol";
@@ -6,7 +6,7 @@ import "../crowdsale/distribution/RefundableCrowdsale.sol";
 
 contract RefundableCrowdsaleImpl is RefundableCrowdsale {
 
-  function RefundableCrowdsaleImpl (
+  constructor (
     uint256 _openingTime,
     uint256 _closingTime,
     uint256 _rate,

contracts/mocks/SafeERC20Helper.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+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

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 
 import "../math/SafeMath.sol";

contracts/mocks/SecureTargetBounty.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 import {Bounty, Target} from "../../contracts/Bounty.sol";
 

contracts/mocks/StandardBurnableTokenMock.sol

@@ -1,11 +1,11 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.4.24;
 
 import "../token/ERC20/StandardBurnableToken.sol";
 
 
 contract StandardBurnableTokenMock is StandardBurnableToken {
 
-  function StandardBurnableTokenMock(address initialAccount, uint initialBalance) public {
+  constructor(address initialAccount, uint initialBalance) public {
     balances[initialAccount] = initialBalance;
     totalSupply_ = initialBalance;
   }

contracts/mocks/StandardTokenMock.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 import "../token/ERC20/StandardToken.sol";
 
@@ -6,7 +6,7 @@ import "../token/ERC20/StandardToken.sol";
 // mock class using StandardToken
 contract StandardTokenMock is StandardToken {
 
-  function StandardTokenMock(address initialAccount, uint256 initialBalance) public {
+  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

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 import "../token/ERC20/ERC20.sol";
 import "../crowdsale/validation/TimedCrowdsale.sol";
@@ -6,7 +6,7 @@ import "../crowdsale/validation/TimedCrowdsale.sol";
 
 contract TimedCrowdsaleImpl is TimedCrowdsale {
 
-  function TimedCrowdsaleImpl (
+  constructor (
     uint256 _openingTime,
     uint256 _closingTime,
     uint256 _rate,

contracts/mocks/WhitelistMock.sol

@@ -1,12 +1,11 @@
-pragma solidity ^0.4.21;
-
-import "../ownership/Whitelist.sol";
+pragma solidity ^0.4.24;
 
+import "../access/Whitelist.sol";
 
 contract WhitelistMock is Whitelist {
 
   function onlyWhitelistedCanDoThis()
-    onlyWhitelisted
+    onlyIfWhitelisted(msg.sender)
     view
     external
   {

contracts/mocks/WhitelistedCrowdsaleImpl.sol

@@ -1,19 +1,19 @@
-pragma solidity ^0.4.21;
+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 ^0.4.21;
+pragma solidity ^0.4.24;
 
 import "./Ownable.sol";
 import "../token/ERC20/ERC20Basic.sol";

contracts/ownership/Claimable.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 
 import "./Ownable.sol";

contracts/ownership/Contactable.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 import "./Ownable.sol";
 

contracts/ownership/DelayedClaimable.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 import "./Claimable.sol";
 

contracts/ownership/HasNoContracts.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 import "./Ownable.sol";
 

contracts/ownership/HasNoEther.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 import "./Ownable.sol";
 
@@ -17,12 +17,12 @@ 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);
   }
 
@@ -36,7 +36,6 @@ contract HasNoEther is Ownable {
    * @dev Transfer all Ether held by the contract to the owner.
    */
   function reclaimEther() external onlyOwner {
-    // solium-disable-next-line security/no-send
-    assert(owner.send(address(this).balance));
+    owner.transfer(address(this).balance);
   }
 }

contracts/ownership/HasNoTokens.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 import "./CanReclaimToken.sol";
 

contracts/ownership/Heritable.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 
 import "./Ownable.sol";
@@ -21,8 +21,15 @@ contract Heritable is Ownable {
 
   event HeirChanged(address indexed owner, address indexed newHeir);
   event OwnerHeartbeated(address indexed owner);
-  event OwnerProclaimedDead(address indexed owner, address indexed heir, uint256 timeOfDeath);
-  event HeirOwnershipClaimed(address indexed previousOwner, address indexed newOwner);
+  event OwnerProclaimedDead(
+    address indexed owner,
+    address indexed heir,
+    uint256 timeOfDeath
+  );
+  event HeirOwnershipClaimed(
+    address indexed previousOwner,
+    address indexed newOwner
+  );
 
 
   /**
@@ -39,7 +46,7 @@ contract Heritable is Ownable {
    * @param _heartbeatTimeout time available for the owner to notify they are alive,
    * before the heir can take ownership.
    */
-  function Heritable(uint256 _heartbeatTimeout) public {
+  constructor(uint256 _heartbeatTimeout) public {
     setHeartbeatTimeout(_heartbeatTimeout);
   }
 
@@ -71,7 +78,7 @@ contract Heritable is Ownable {
    */
   function removeHeir() public onlyOwner {
     heartbeat();
-    heir_ = 0;
+    heir_ = address(0);
   }
 
   /**
@@ -106,7 +113,9 @@ contract Heritable is Ownable {
     timeOfDeath_ = 0;
   }
 
-  function setHeartbeatTimeout(uint256 newHeartbeatTimeout) internal onlyOwner {
+  function setHeartbeatTimeout(uint256 newHeartbeatTimeout)
+    internal onlyOwner
+  {
     require(ownerLives());
     heartbeatTimeout_ = newHeartbeatTimeout;
   }

contracts/ownership/NoOwner.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 import "./HasNoEther.sol";
 import "./HasNoTokens.sol";

contracts/ownership/Ownable.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 
 /**
@@ -10,14 +10,18 @@ contract Ownable {
   address public owner;
 
 
-  event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
+  event OwnershipRenounced(address indexed previousOwner);
+  event OwnershipTransferred(
+    address indexed previousOwner,
+    address indexed newOwner
+  );
 
 
   /**
    * @dev The Ownable constructor sets the original `owner` of the contract to the sender
    * account.
    */
-  function Ownable() public {
+  constructor() public {
     owner = msg.sender;
   }
 
@@ -30,13 +34,31 @@ contract Ownable {
   }
 
   /**
-   * @dev Allows the current owner to transfer control of the contract to a newOwner.
-   * @param newOwner The address to transfer ownership to.
+   * @dev Allows the current owner to relinquish control of the contract.
+   * @notice Renouncing to ownership will leave the contract without an owner.
+   * It will not be possible to call the functions with the `onlyOwner`
+   * modifier anymore.
    */
-  function transferOwnership(address newOwner) public onlyOwner {
-    require(newOwner != address(0));
-    emit OwnershipTransferred(owner, newOwner);
-    owner = newOwner;
+  function renounceOwnership() public onlyOwner {
+    emit OwnershipRenounced(owner);
+    owner = address(0);
   }
 
+  /**
+   * @dev Allows the current owner to transfer control of the contract to a newOwner.
+   * @param _newOwner The address to transfer ownership to.
+   */
+  function transferOwnership(address _newOwner) public onlyOwner {
+    _transferOwnership(_newOwner);
+  }
+
+  /**
+   * @dev Transfers control of the contract to a newOwner.
+   * @param _newOwner The address to transfer ownership to.
+   */
+  function _transferOwnership(address _newOwner) internal {
+    require(_newOwner != address(0));
+    emit OwnershipTransferred(owner, _newOwner);
+    owner = _newOwner;
+  }
 }

contracts/ownership/Superuser.sol

@@ -0,0 +1,62 @@
+pragma solidity ^0.4.24;
+
+
+import "./Ownable.sol";
+import "./rbac/RBAC.sol";
+
+
+/**
+ * @title Superuser
+ * @dev The Superuser contract defines a single superuser who can transfer the ownership 
+ * of a contract to a new address, even if he is not the owner. 
+ * A superuser can transfer his role to a new address. 
+ */
+contract Superuser is Ownable, RBAC {
+  string public constant ROLE_SUPERUSER = "superuser";
+
+  constructor () public {
+    addRole(msg.sender, ROLE_SUPERUSER);
+  }
+
+  /**
+   * @dev Throws if called by any account that's not a superuser.
+   */
+  modifier onlySuperuser() {
+    checkRole(msg.sender, ROLE_SUPERUSER);
+    _;
+  }
+
+  modifier onlyOwnerOrSuperuser() {
+    require(msg.sender == owner || isSuperuser(msg.sender));
+    _;
+  }
+
+  /**
+   * @dev getter to determine if address has superuser role
+   */
+  function isSuperuser(address _addr)
+    public
+    view
+    returns (bool)
+  {
+    return hasRole(_addr, ROLE_SUPERUSER);
+  }
+
+  /**
+   * @dev Allows the current superuser to transfer his role to a newSuperuser.
+   * @param _newSuperuser The address to transfer ownership to.
+   */
+  function transferSuperuser(address _newSuperuser) public onlySuperuser {
+    require(_newSuperuser != address(0));
+    removeRole(msg.sender, ROLE_SUPERUSER);
+    addRole(_newSuperuser, ROLE_SUPERUSER);
+  }
+
+  /**
+   * @dev Allows the current superuser or owner to transfer control of the contract to a newOwner.
+   * @param _newOwner The address to transfer ownership to.
+   */
+  function transferOwnership(address _newOwner) public onlyOwnerOrSuperuser {
+    _transferOwnership(_newOwner);
+  }
+}

contracts/ownership/Whitelist.sol

@@ -1,81 +0,0 @@
-pragma solidity ^0.4.21;
-
-
-import "./Ownable.sol";
-
-
-/**
- * @title Whitelist
- * @dev The Whitelist contract has a whitelist of addresses, and provides basic authorization control functions.
- * @dev This simplifies the implementation of "user permissions".
- */
-contract Whitelist is Ownable {
-  mapping(address => bool) public whitelist;
-
-  event WhitelistedAddressAdded(address addr);
-  event WhitelistedAddressRemoved(address addr);
-
-  /**
-   * @dev Throws if called by any account that's not whitelisted.
-   */
-  modifier onlyWhitelisted() {
-    require(whitelist[msg.sender]);
-    _;
-  }
-
-  /**
-   * @dev add an address to the whitelist
-   * @param addr address
-   * @return true if the address was added to the whitelist, false if the address was already in the whitelist
-   */
-  function addAddressToWhitelist(address addr) onlyOwner public returns(bool success) {
-    if (!whitelist[addr]) {
-      whitelist[addr] = true;
-      emit WhitelistedAddressAdded(addr);
-      success = true;
-    }
-  }
-
-  /**
-   * @dev add addresses to the whitelist
-   * @param addrs 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[] addrs) onlyOwner public returns(bool success) {
-    for (uint256 i = 0; i < addrs.length; i++) {
-      if (addAddressToWhitelist(addrs[i])) {
-        success = true;
-      }
-    }
-  }
-
-  /**
-   * @dev remove an address from the whitelist
-   * @param addr 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 addr) onlyOwner public returns(bool success) {
-    if (whitelist[addr]) {
-      whitelist[addr] = false;
-      emit WhitelistedAddressRemoved(addr);
-      success = true;
-    }
-  }
-
-  /**
-   * @dev remove addresses from the whitelist
-   * @param addrs 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[] addrs) onlyOwner public returns(bool success) {
-    for (uint256 i = 0; i < addrs.length; i++) {
-      if (removeAddressFromWhitelist(addrs[i])) {
-        success = true;
-      }
-    }
-  }
-
-}

contracts/ownership/rbac/RBAC.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 import "./Roles.sol";
 
@@ -7,95 +7,95 @@ import "./Roles.sol";
  * @title RBAC (Role-Based Access Control)
  * @author Matt Condon (@Shrugs)
  * @dev Stores and provides setters and getters for roles and addresses.
- * @dev Supports unlimited numbers of roles and addresses.
- * @dev See //contracts/mocks/RBACMock.sol for an example of usage.
+ * 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.
+ * for you to write your own implementation of this interface using Enums or similar.
  * It's also recommended that you define constants in the contract, like ROLE_ADMIN below,
- *  to avoid typos.
+ * to avoid typos.
  */
 contract RBAC {
   using Roles for Roles.Role;
 
   mapping (string => Roles.Role) private roles;
 
-  event RoleAdded(address addr, string roleName);
-  event RoleRemoved(address addr, string roleName);
+  event RoleAdded(address indexed operator, string role);
+  event RoleRemoved(address indexed operator, string role);
 
   /**
    * @dev reverts if addr does not have role
-   * @param addr address
-   * @param roleName the name of the role
+   * @param _operator address
+   * @param _role the name of the role
    * // reverts
    */
-  function checkRole(address addr, string roleName)
+  function checkRole(address _operator, string _role)
     view
     public
   {
-    roles[roleName].check(addr);
+    roles[_role].check(_operator);
   }
 
   /**
    * @dev determine if addr has role
-   * @param addr address
-   * @param roleName the name of the role
+   * @param _operator address
+   * @param _role the name of the role
    * @return bool
    */
-  function hasRole(address addr, string roleName)
+  function hasRole(address _operator, string _role)
     view
     public
     returns (bool)
   {
-    return roles[roleName].has(addr);
+    return roles[_role].has(_operator);
   }
 
   /**
    * @dev add a role to an address
-   * @param addr address
-   * @param roleName the name of the role
+   * @param _operator address
+   * @param _role the name of the role
    */
-  function addRole(address addr, string roleName)
+  function addRole(address _operator, string _role)
     internal
   {
-    roles[roleName].add(addr);
-    emit RoleAdded(addr, roleName);
+    roles[_role].add(_operator);
+    emit RoleAdded(_operator, _role);
   }
 
   /**
    * @dev remove a role from an address
-   * @param addr address
-   * @param roleName the name of the role
+   * @param _operator address
+   * @param _role the name of the role
    */
-  function removeRole(address addr, string roleName)
+  function removeRole(address _operator, string _role)
     internal
   {
-    roles[roleName].remove(addr);
-    emit RoleRemoved(addr, roleName);
+    roles[_role].remove(_operator);
+    emit RoleRemoved(_operator, _role);
   }
 
   /**
    * @dev modifier to scope access to a single role (uses msg.sender as addr)
-   * @param roleName the name of the role
+   * @param _role the name of the role
    * // reverts
    */
-  modifier onlyRole(string roleName)
+  modifier onlyRole(string _role)
   {
-    checkRole(msg.sender, roleName);
+    checkRole(msg.sender, _role);
     _;
   }
 
   /**
    * @dev modifier to scope access to a set of roles (uses msg.sender as addr)
-   * @param roleNames the names of the roles to scope access to
+   * @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[] roleNames) {
+  // modifier onlyRoles(string[] _roles) {
   //     bool hasAnyRole = false;
-  //     for (uint8 i = 0; i < roleNames.length; i++) {
-  //         if (hasRole(msg.sender, roleNames[i])) {
+  //     for (uint8 i = 0; i < _roles.length; i++) {
+  //         if (hasRole(msg.sender, _roles[i])) {
   //             hasAnyRole = true;
   //             break;
   //         }

contracts/ownership/rbac/Roles.sol

@@ -1,11 +1,11 @@
-pragma solidity ^0.4.21;
+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 {

contracts/payment/ConditionalEscrow.sol

@@ -0,0 +1,22 @@
+pragma solidity ^0.4.23;
+
+import "./Escrow.sol";
+
+
+/**
+ * @title ConditionalEscrow
+ * @dev Base abstract escrow to only allow withdrawal if a condition is met.
+ */
+contract ConditionalEscrow is Escrow {
+  /**
+  * @dev Returns whether an address is allowed to withdraw their funds. To be
+  * implemented by derived contracts.
+  * @param _payee The destination address of the funds.
+  */
+  function withdrawalAllowed(address _payee) public view returns (bool);
+
+  function withdraw(address _payee) public {
+    require(withdrawalAllowed(_payee));
+    super.withdraw(_payee);
+  }
+}

contracts/payment/Escrow.sol

@@ -0,0 +1,51 @@
+pragma solidity ^0.4.23;
+
+import "../math/SafeMath.sol";
+import "../ownership/Ownable.sol";
+
+
+/**
+ * @title Escrow
+ * @dev Base escrow contract, holds funds destinated to a payee until they
+ * withdraw them. The contract that uses the escrow as its payment method
+ * should be its owner, and provide public methods redirecting to the escrow's
+ * deposit and withdraw.
+ */
+contract Escrow is Ownable {
+  using SafeMath for uint256;
+
+  event Deposited(address indexed payee, uint256 weiAmount);
+  event Withdrawn(address indexed payee, uint256 weiAmount);
+
+  mapping(address => uint256) private deposits;
+
+  function depositsOf(address _payee) public view returns (uint256) {
+    return deposits[_payee];
+  }
+
+  /**
+  * @dev Stores the sent amount as credit to be withdrawn.
+  * @param _payee The destination address of the funds.
+  */
+  function deposit(address _payee) public onlyOwner payable {
+    uint256 amount = msg.value;
+    deposits[_payee] = deposits[_payee].add(amount);
+
+    emit Deposited(_payee, amount);
+  }
+
+  /**
+  * @dev Withdraw accumulated balance for a payee.
+  * @param _payee The address whose funds will be withdrawn and transferred to.
+  */
+  function withdraw(address _payee) public onlyOwner {
+    uint256 payment = deposits[_payee];
+    assert(address(this).balance >= payment);
+
+    deposits[_payee] = 0;
+
+    _payee.transfer(payment);
+
+    emit Withdrawn(_payee, payment);
+  }
+}

contracts/payment/PullPayment.sol

@@ -1,43 +1,42 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
-
-import "../math/SafeMath.sol";
+import "./Escrow.sol";
 
 
 /**
  * @title PullPayment
  * @dev Base contract supporting async send for pull payments. Inherit from this
- * contract and use asyncSend instead of send or transfer.
+ * contract and use asyncTransfer instead of send or transfer.
  */
 contract PullPayment {
-  using SafeMath for uint256;
+  Escrow private escrow;
 
-  mapping(address => uint256) public payments;
-  uint256 public totalPayments;
+  constructor() public {
+    escrow = new Escrow();
+  }
 
   /**
   * @dev Withdraw accumulated balance, called by payee.
   */
   function withdrawPayments() public {
     address payee = msg.sender;
-    uint256 payment = payments[payee];
+    escrow.withdraw(payee);
+  }
 
-    require(payment != 0);
-    require(address(this).balance >= payment);
-
-    totalPayments = totalPayments.sub(payment);
-    payments[payee] = 0;
-
-    payee.transfer(payment);
+  /**
+  * @dev Returns the credit owed to an address.
+  * @param _dest The creditor's address.
+  */
+  function payments(address _dest) public view returns (uint256) {
+    return escrow.depositsOf(_dest);
   }
 
   /**
   * @dev Called by the payer to store the sent amount as credit to be pulled.
-  * @param dest The destination address of the funds.
-  * @param amount The amount to transfer.
+  * @param _dest The destination address of the funds.
+  * @param _amount The amount to transfer.
   */
-  function asyncSend(address dest, uint256 amount) internal {
-    payments[dest] = payments[dest].add(amount);
-    totalPayments = totalPayments.add(amount);
+  function asyncTransfer(address _dest, uint256 _amount) internal {
+    escrow.deposit.value(_amount)(_dest);
   }
 }

contracts/payment/RefundEscrow.sol

@@ -0,0 +1,74 @@
+pragma solidity ^0.4.23;
+
+import "./ConditionalEscrow.sol";
+import "../ownership/Ownable.sol";
+
+
+/**
+ * @title RefundEscrow
+ * @dev Escrow that holds funds for a beneficiary, deposited from multiple parties.
+ * The contract owner may close the deposit period, and allow for either withdrawal
+ * by the beneficiary, or refunds to the depositors.
+ */
+contract RefundEscrow is Ownable, ConditionalEscrow {
+  enum State { Active, Refunding, Closed }
+
+  event Closed();
+  event RefundsEnabled();
+
+  State public state;
+  address public beneficiary;
+
+  /**
+   * @dev Constructor.
+   * @param _beneficiary The beneficiary of the deposits.
+   */
+  constructor(address _beneficiary) public {
+    require(_beneficiary != address(0));
+    beneficiary = _beneficiary;
+    state = State.Active;
+  }
+
+  /**
+   * @dev Stores funds that may later be refunded.
+   * @param _refundee The address funds will be sent to if a refund occurs.
+   */
+  function deposit(address _refundee) public payable {
+    require(state == State.Active);
+    super.deposit(_refundee);
+  }
+
+  /**
+   * @dev Allows for the beneficiary to withdraw their funds, rejecting
+   * further deposits.
+   */
+  function close() public onlyOwner {
+    require(state == State.Active);
+    state = State.Closed;
+    emit Closed();
+  }
+
+  /**
+   * @dev Allows for refunds to take place, rejecting further deposits.
+   */
+  function enableRefunds() public onlyOwner {
+    require(state == State.Active);
+    state = State.Refunding;
+    emit RefundsEnabled();
+  }
+
+  /**
+   * @dev Withdraws the beneficiary's funds.
+   */
+  function beneficiaryWithdraw() public {
+    require(state == State.Closed);
+    beneficiary.transfer(address(this).balance);
+  }
+
+  /**
+   * @dev Returns whether refundees can withdraw their deposits (be refunded).
+   */
+  function withdrawalAllowed(address _payee) public view returns (bool) {
+    return state == State.Refunding;
+  }
+}

contracts/payment/SplitPayment.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 import "../math/SafeMath.sol";
 
@@ -21,7 +21,7 @@ contract SplitPayment {
   /**
    * @dev Constructor
    */
-  function SplitPayment(address[] _payees, uint256[] _shares) public payable {
+  constructor(address[] _payees, uint256[] _shares) public payable {
     require(_payees.length == _shares.length);
 
     for (uint256 i = 0; i < _payees.length; i++) {
@@ -43,7 +43,11 @@ contract SplitPayment {
     require(shares[payee] > 0);
 
     uint256 totalReceived = address(this).balance.add(totalReleased);
-    uint256 payment = totalReceived.mul(shares[payee]).div(totalShares).sub(released[payee]);
+    uint256 payment = totalReceived.mul(
+      shares[payee]).div(
+        totalShares).sub(
+          released[payee]
+    );
 
     require(payment != 0);
     require(address(this).balance >= payment);