diff --git a/.travis.yml b/.travis.yml
index 3d0f5d5107a..eb47674bf6a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -6,13 +6,6 @@ node_js:
   - "6"
 cache:
   yarn: true
-env:
-  -
-  - SOLIDITY_COVERAGE=true
-matrix:
-  fast_finish: true
-  allow_failures:
-    - env: SOLIDITY_COVERAGE=true
 before_script:
   - truffle version
   - yarn list
diff --git a/contracts/Bounty.sol b/contracts/Bounty.sol
index 1d00ca917da..f3b3cd0b909 100644
--- a/contracts/Bounty.sol
+++ b/contracts/Bounty.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 
 import './payment/PullPayment.sol';
diff --git a/contracts/DayLimit.sol b/contracts/DayLimit.sol
index 6efe8b6617d..9964bd536fd 100644
--- a/contracts/DayLimit.sol
+++ b/contracts/DayLimit.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 /**
  * @title DayLimit
@@ -59,7 +59,7 @@ contract DayLimit {
    * @dev Private function to determine today's index
    * @return uint256 of today's index.
    */
-  function today() private constant returns (uint256) {
+  function today() private view returns (uint256) {
     return now / 1 days;
   }
 
diff --git a/contracts/ECRecovery.sol b/contracts/ECRecovery.sol
index de32838a1fd..3876ca6e830 100644
--- a/contracts/ECRecovery.sol
+++ b/contracts/ECRecovery.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 
 /**
@@ -14,7 +14,7 @@ library ECRecovery {
    * @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 constant returns (address) {
+  function recover(bytes32 hash, bytes sig) public pure returns (address) {
     bytes32 r;
     bytes32 s;
     uint8 v;
diff --git a/contracts/LimitBalance.sol b/contracts/LimitBalance.sol
index 32ec46d1fcb..a3297418404 100644
--- a/contracts/LimitBalance.sol
+++ b/contracts/LimitBalance.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 
 /**
diff --git a/contracts/MerkleProof.sol b/contracts/MerkleProof.sol
index 1703ee4eaea..e638c8e9da6 100644
--- a/contracts/MerkleProof.sol
+++ b/contracts/MerkleProof.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 /*
  * @title MerkleProof
@@ -13,7 +13,7 @@ library MerkleProof {
    * @param _root Merkle root
    * @param _leaf Leaf of Merkle tree
    */
-  function verifyProof(bytes _proof, bytes32 _root, bytes32 _leaf) constant returns (bool) {
+  function verifyProof(bytes _proof, bytes32 _root, bytes32 _leaf) pure returns (bool) {
     // Check if proof length is a multiple of 32
     if (_proof.length % 32 != 0) return false;
 
diff --git a/contracts/ReentrancyGuard.sol b/contracts/ReentrancyGuard.sol
index fa9e7d52e5d..461c431b0dc 100644
--- a/contracts/ReentrancyGuard.sol
+++ b/contracts/ReentrancyGuard.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 /**
  * @title Helps contracts guard agains rentrancy attacks.
diff --git a/contracts/crowdsale/CappedCrowdsale.sol b/contracts/crowdsale/CappedCrowdsale.sol
index a9c54ac905a..972c1fc1bee 100644
--- a/contracts/crowdsale/CappedCrowdsale.sol
+++ b/contracts/crowdsale/CappedCrowdsale.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 import '../math/SafeMath.sol';
 import './Crowdsale.sol';
@@ -19,14 +19,14 @@ contract CappedCrowdsale is Crowdsale {
 
   // overriding Crowdsale#validPurchase to add extra cap logic
   // @return true if investors can buy at the moment
-  function validPurchase() internal constant returns (bool) {
+  function validPurchase() internal view returns (bool) {
     bool withinCap = weiRaised.add(msg.value) <= cap;
     return super.validPurchase() && withinCap;
   }
 
   // overriding Crowdsale#hasEnded to add cap logic
   // @return true if crowdsale event has ended
-  function hasEnded() public constant returns (bool) {
+  function hasEnded() public view returns (bool) {
     bool capReached = weiRaised >= cap;
     return super.hasEnded() || capReached;
   }
diff --git a/contracts/crowdsale/Crowdsale.sol b/contracts/crowdsale/Crowdsale.sol
index 26ed8df8521..27ccac3f0d9 100644
--- a/contracts/crowdsale/Crowdsale.sol
+++ b/contracts/crowdsale/Crowdsale.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 import '../token/MintableToken.sol';
 import '../math/SafeMath.sol';
@@ -91,14 +91,14 @@ contract Crowdsale {
   }
 
   // @return true if the transaction can buy tokens
-  function validPurchase() internal constant returns (bool) {
+  function validPurchase() internal view returns (bool) {
     bool withinPeriod = now >= startTime && now <= endTime;
     bool nonZeroPurchase = msg.value != 0;
     return withinPeriod && nonZeroPurchase;
   }
 
   // @return true if crowdsale event has ended
-  function hasEnded() public constant returns (bool) {
+  function hasEnded() public view returns (bool) {
     return now > endTime;
   }
 
diff --git a/contracts/crowdsale/FinalizableCrowdsale.sol b/contracts/crowdsale/FinalizableCrowdsale.sol
index 49a291c4b61..c8501dadd1e 100644
--- a/contracts/crowdsale/FinalizableCrowdsale.sol
+++ b/contracts/crowdsale/FinalizableCrowdsale.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 import '../math/SafeMath.sol';
 import '../ownership/Ownable.sol';
diff --git a/contracts/crowdsale/RefundVault.sol b/contracts/crowdsale/RefundVault.sol
index fb721d17a4a..62d7599dd0d 100644
--- a/contracts/crowdsale/RefundVault.sol
+++ b/contracts/crowdsale/RefundVault.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 import '../math/SafeMath.sol';
 import '../ownership/Ownable.sol';
diff --git a/contracts/crowdsale/RefundableCrowdsale.sol b/contracts/crowdsale/RefundableCrowdsale.sol
index f04f643ebff..c468fcf341c 100644
--- a/contracts/crowdsale/RefundableCrowdsale.sol
+++ b/contracts/crowdsale/RefundableCrowdsale.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 
 import '../math/SafeMath.sol';
@@ -53,7 +53,7 @@ contract RefundableCrowdsale is FinalizableCrowdsale {
     super.finalization();
   }
 
-  function goalReached() public constant returns (bool) {
+  function goalReached() public view returns (bool) {
     return weiRaised >= goal;
   }
 
diff --git a/contracts/examples/SampleCrowdsale.sol b/contracts/examples/SampleCrowdsale.sol
index 0adc487b60b..a83b8856db3 100644
--- a/contracts/examples/SampleCrowdsale.sol
+++ b/contracts/examples/SampleCrowdsale.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 import "../crowdsale/CappedCrowdsale.sol";
 import "../crowdsale/RefundableCrowdsale.sol";
diff --git a/contracts/examples/SimpleToken.sol b/contracts/examples/SimpleToken.sol
index f0ad644db27..2381a7162d8 100644
--- a/contracts/examples/SimpleToken.sol
+++ b/contracts/examples/SimpleToken.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 
 import "../token/StandardToken.sol";
diff --git a/contracts/lifecycle/Destructible.sol b/contracts/lifecycle/Destructible.sol
index 9c24474b790..e1b3174bcc3 100644
--- a/contracts/lifecycle/Destructible.sol
+++ b/contracts/lifecycle/Destructible.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 
 import "../ownership/Ownable.sol";
diff --git a/contracts/lifecycle/Migrations.sol b/contracts/lifecycle/Migrations.sol
index f389cca9977..59d1f0bf3e5 100644
--- a/contracts/lifecycle/Migrations.sol
+++ b/contracts/lifecycle/Migrations.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 
 import '../ownership/Ownable.sol';
diff --git a/contracts/lifecycle/Pausable.sol b/contracts/lifecycle/Pausable.sol
index 9c3cc307baa..d7341ead020 100644
--- a/contracts/lifecycle/Pausable.sol
+++ b/contracts/lifecycle/Pausable.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 
 import "../ownership/Ownable.sol";
diff --git a/contracts/lifecycle/TokenDestructible.sol b/contracts/lifecycle/TokenDestructible.sol
index e29d69b63a2..1c3324feac2 100644
--- a/contracts/lifecycle/TokenDestructible.sol
+++ b/contracts/lifecycle/TokenDestructible.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 
 import "../ownership/Ownable.sol";
diff --git a/contracts/math/Math.sol b/contracts/math/Math.sol
index 3d016c0acd5..5d09ee6ff31 100644
--- a/contracts/math/Math.sol
+++ b/contracts/math/Math.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 /**
  * @title Math
@@ -6,19 +6,19 @@ pragma solidity ^0.4.11;
  */
 
 library Math {
-  function max64(uint64 a, uint64 b) internal constant returns (uint64) {
+  function max64(uint64 a, uint64 b) internal pure returns (uint64) {
     return a >= b ? a : b;
   }
 
-  function min64(uint64 a, uint64 b) internal constant returns (uint64) {
+  function min64(uint64 a, uint64 b) internal pure returns (uint64) {
     return a < b ? a : b;
   }
 
-  function max256(uint256 a, uint256 b) internal constant returns (uint256) {
+  function max256(uint256 a, uint256 b) internal pure returns (uint256) {
     return a >= b ? a : b;
   }
 
-  function min256(uint256 a, uint256 b) internal constant returns (uint256) {
+  function min256(uint256 a, uint256 b) internal pure returns (uint256) {
     return a < b ? a : b;
   }
 }
diff --git a/contracts/math/SafeMath.sol b/contracts/math/SafeMath.sol
index 05ad6ee171e..234daf65656 100644
--- a/contracts/math/SafeMath.sol
+++ b/contracts/math/SafeMath.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 
 /**
@@ -6,7 +6,7 @@ pragma solidity ^0.4.11;
  * @dev Math operations with safety checks that throw on error
  */
 library SafeMath {
-  function mul(uint256 a, uint256 b) internal constant returns (uint256) {
+  function mul(uint256 a, uint256 b) internal pure returns (uint256) {
     if (a == 0) {
       return 0;
     }
@@ -15,19 +15,19 @@ library SafeMath {
     return c;
   }
 
-  function div(uint256 a, uint256 b) internal constant returns (uint256) {
+  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 sub(uint256 a, uint256 b) internal constant returns (uint256) {
+  function sub(uint256 a, uint256 b) internal pure returns (uint256) {
     assert(b <= a);
     return a - b;
   }
 
-  function add(uint256 a, uint256 b) internal constant returns (uint256) {
+  function add(uint256 a, uint256 b) internal pure returns (uint256) {
     uint256 c = a + b;
     assert(c >= a);
     return c;
diff --git a/contracts/ownership/CanReclaimToken.sol b/contracts/ownership/CanReclaimToken.sol
index d26212df97c..d948393ac38 100644
--- a/contracts/ownership/CanReclaimToken.sol
+++ b/contracts/ownership/CanReclaimToken.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 import "./Ownable.sol";
 import "../token/ERC20Basic.sol";
diff --git a/contracts/ownership/Claimable.sol b/contracts/ownership/Claimable.sol
index 299f2c8aacd..556a353cfdd 100644
--- a/contracts/ownership/Claimable.sol
+++ b/contracts/ownership/Claimable.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 
 import './Ownable.sol';
diff --git a/contracts/ownership/Contactable.sol b/contracts/ownership/Contactable.sol
index ed0c50dcd0f..2b6898f615d 100644
--- a/contracts/ownership/Contactable.sol
+++ b/contracts/ownership/Contactable.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 import './Ownable.sol';
 
diff --git a/contracts/ownership/DelayedClaimable.sol b/contracts/ownership/DelayedClaimable.sol
index 0384b436b38..0091fa68e80 100644
--- a/contracts/ownership/DelayedClaimable.sol
+++ b/contracts/ownership/DelayedClaimable.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 
 import './Claimable.sol';
diff --git a/contracts/ownership/HasNoContracts.sol b/contracts/ownership/HasNoContracts.sol
index 19b363d46db..1b7387530b7 100644
--- a/contracts/ownership/HasNoContracts.sol
+++ b/contracts/ownership/HasNoContracts.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 import "./Ownable.sol";
 
diff --git a/contracts/ownership/HasNoEther.sol b/contracts/ownership/HasNoEther.sol
index 63b4ef65c73..3f83096772b 100644
--- a/contracts/ownership/HasNoEther.sol
+++ b/contracts/ownership/HasNoEther.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 import "./Ownable.sol";
 
diff --git a/contracts/ownership/HasNoTokens.sol b/contracts/ownership/HasNoTokens.sol
index 3f91ad24a0e..cce530bf623 100644
--- a/contracts/ownership/HasNoTokens.sol
+++ b/contracts/ownership/HasNoTokens.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 import "./CanReclaimToken.sol";
 
diff --git a/contracts/ownership/NoOwner.sol b/contracts/ownership/NoOwner.sol
index c0ef7f4dcb6..160d5b57de2 100644
--- a/contracts/ownership/NoOwner.sol
+++ b/contracts/ownership/NoOwner.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 import "./HasNoEther.sol";
 import "./HasNoTokens.sol";
diff --git a/contracts/ownership/Ownable.sol b/contracts/ownership/Ownable.sol
index 9e2c2f884b7..67ac79ff1bd 100644
--- a/contracts/ownership/Ownable.sol
+++ b/contracts/ownership/Ownable.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 
 /**
diff --git a/contracts/payment/PullPayment.sol b/contracts/payment/PullPayment.sol
index 4a0924fa739..5e7cbf740b1 100644
--- a/contracts/payment/PullPayment.sol
+++ b/contracts/payment/PullPayment.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 
 import '../math/SafeMath.sol';
diff --git a/contracts/payment/SplitPayment.sol b/contracts/payment/SplitPayment.sol
index c32ecba39f4..78538e3ec52 100644
--- a/contracts/payment/SplitPayment.sol
+++ b/contracts/payment/SplitPayment.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 import '../math/SafeMath.sol';
 
diff --git a/contracts/token/BasicToken.sol b/contracts/token/BasicToken.sol
index a45157f81f8..0bd7603fbec 100644
--- a/contracts/token/BasicToken.sol
+++ b/contracts/token/BasicToken.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 
 import './ERC20Basic.sol';
@@ -35,7 +35,7 @@ contract BasicToken is ERC20Basic {
   * @param _owner The address to query the the balance of.
   * @return An uint256 representing the amount owned by the passed address.
   */
-  function balanceOf(address _owner) public constant returns (uint256 balance) {
+  function balanceOf(address _owner) public view returns (uint256 balance) {
     return balances[_owner];
   }
 
diff --git a/contracts/token/BurnableToken.sol b/contracts/token/BurnableToken.sol
index c155bd1883a..2ff3b1fabcb 100644
--- a/contracts/token/BurnableToken.sol
+++ b/contracts/token/BurnableToken.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.13;
+pragma solidity ^0.4.18;
 
 import './StandardToken.sol';
 
diff --git a/contracts/token/DetailedERC20.sol b/contracts/token/DetailedERC20.sol
index c61cde2e975..a08236305e6 100644
--- a/contracts/token/DetailedERC20.sol
+++ b/contracts/token/DetailedERC20.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 import './ERC20.sol';
 
diff --git a/contracts/token/ERC20.sol b/contracts/token/ERC20.sol
index ca36d737b9a..28ffc01658a 100644
--- a/contracts/token/ERC20.sol
+++ b/contracts/token/ERC20.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 
 import './ERC20Basic.sol';
@@ -9,7 +9,7 @@ import './ERC20Basic.sol';
  * @dev see https://github.com/ethereum/EIPs/issues/20
  */
 contract ERC20 is ERC20Basic {
-  function allowance(address owner, address spender) public constant returns (uint256);
+  function allowance(address owner, address spender) public view returns (uint256);
   function transferFrom(address from, address to, uint256 value) public returns (bool);
   function approve(address spender, uint256 value) public returns (bool);
   event Approval(address indexed owner, address indexed spender, uint256 value);
diff --git a/contracts/token/ERC20Basic.sol b/contracts/token/ERC20Basic.sol
index 76e0704bae4..c972edac66f 100644
--- a/contracts/token/ERC20Basic.sol
+++ b/contracts/token/ERC20Basic.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 
 /**
@@ -8,7 +8,7 @@ pragma solidity ^0.4.11;
  */
 contract ERC20Basic {
   uint256 public totalSupply;
-  function balanceOf(address who) public constant returns (uint256);
+  function balanceOf(address who) public view returns (uint256);
   function transfer(address to, uint256 value) public returns (bool);
   event Transfer(address indexed from, address indexed to, uint256 value);
 }
diff --git a/contracts/token/MintableToken.sol b/contracts/token/MintableToken.sol
index ba2454e93ae..53f577d46c3 100644
--- a/contracts/token/MintableToken.sol
+++ b/contracts/token/MintableToken.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 
 import './StandardToken.sol';
diff --git a/contracts/token/PausableToken.sol b/contracts/token/PausableToken.sol
index 428fb990b53..0af9971c0ff 100644
--- a/contracts/token/PausableToken.sol
+++ b/contracts/token/PausableToken.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 import './StandardToken.sol';
 import '../lifecycle/Pausable.sol';
diff --git a/contracts/token/SafeERC20.sol b/contracts/token/SafeERC20.sol
index cffa8b9f874..64d10039145 100644
--- a/contracts/token/SafeERC20.sol
+++ b/contracts/token/SafeERC20.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 import './ERC20Basic.sol';
 import './ERC20.sol';
diff --git a/contracts/token/StandardToken.sol b/contracts/token/StandardToken.sol
index 3d648937d1c..343d36e1fe1 100644
--- a/contracts/token/StandardToken.sol
+++ b/contracts/token/StandardToken.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 
 import './BasicToken.sol';
@@ -57,7 +57,7 @@ contract StandardToken is ERC20, BasicToken {
    * @param _spender address The address which will spend the funds.
    * @return A uint256 specifying the amount of tokens still available for the spender.
    */
-  function allowance(address _owner, address _spender) public constant returns (uint256) {
+  function allowance(address _owner, address _spender) public view returns (uint256) {
     return allowed[_owner][_spender];
   }
 
diff --git a/contracts/token/TokenTimelock.sol b/contracts/token/TokenTimelock.sol
index f4255fbbf0b..557fc6ed6b2 100644
--- a/contracts/token/TokenTimelock.sol
+++ b/contracts/token/TokenTimelock.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 
 import './ERC20Basic.sol';
diff --git a/contracts/token/TokenVesting.sol b/contracts/token/TokenVesting.sol
index 7fb33b89678..14373d15b26 100644
--- a/contracts/token/TokenVesting.sol
+++ b/contracts/token/TokenVesting.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 import './ERC20Basic.sol';
 import './SafeERC20.sol';
@@ -91,7 +91,7 @@ contract TokenVesting is Ownable {
    * @dev Calculates the amount that has already vested but hasn't been released yet.
    * @param token ERC20 token which is being vested
    */
-  function releasableAmount(ERC20Basic token) public constant returns (uint256) {
+  function releasableAmount(ERC20Basic token) public view returns (uint256) {
     return vestedAmount(token).sub(released[token]);
   }
 
@@ -99,7 +99,7 @@ contract TokenVesting is Ownable {
    * @dev Calculates the amount that has already vested.
    * @param token ERC20 token which is being vested
    */
-  function vestedAmount(ERC20Basic token) public constant returns (uint256) {
+  function vestedAmount(ERC20Basic token) public view returns (uint256) {
     uint256 currentBalance = token.balanceOf(this);
     uint256 totalBalance = currentBalance.add(released[token]);
 
diff --git a/package-lock.json b/package-lock.json
index 52be4767733..1cd69bf4a56 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -2704,6 +2704,12 @@
         "secp256k1": "3.3.0"
       }
     },
+    "he": {
+      "version": "1.1.1",
+      "resolved": "https://registry.npmjs.org/he/-/he-1.1.1.tgz",
+      "integrity": "sha1-k0EP0hsAlzUVH4howvJx80J+I/0=",
+      "dev": true
+    },
     "hmac-drbg": {
       "version": "1.0.1",
       "resolved": "https://registry.npmjs.org/hmac-drbg/-/hmac-drbg-1.0.1.tgz",
@@ -5281,14 +5287,14 @@
       "dev": true
     },
     "truffle": {
-      "version": "3.4.8",
-      "resolved": "https://registry.npmjs.org/truffle/-/truffle-3.4.8.tgz",
-      "integrity": "sha512-UeMrofHcguSwfAa5Oy3+arWPWb5zd28stySKIanNhzByV1rcUy3WhxE5up4LBOxAPz+OsH1nQ02kqIcBZDwxIw==",
+      "version": "4.0.1",
+      "resolved": "https://registry.npmjs.org/truffle/-/truffle-4.0.1.tgz",
+      "integrity": "sha512-PybO+GMq3AvsfCWfEx4sbuaJlDL19iR8Ff20cO0TtP599N5JbMLlhwlffvVInPgFjP+F11vjSOYj3hT8fONs5A==",
       "dev": true,
       "requires": {
-        "mocha": "3.5.0",
+        "mocha": "3.5.3",
         "original-require": "1.0.1",
-        "solc": "0.4.13"
+        "solc": "0.4.18"
       },
       "dependencies": {
         "commander": {
@@ -5321,9 +5327,9 @@
           }
         },
         "mocha": {
-          "version": "3.5.0",
-          "resolved": "https://registry.npmjs.org/mocha/-/mocha-3.5.0.tgz",
-          "integrity": "sha512-pIU2PJjrPYvYRqVpjXzj76qltO9uBYI7woYAMoxbSefsa+vqAfptjoeevd6bUgwD0mPIO+hv9f7ltvsNreL2PA==",
+          "version": "3.5.3",
+          "resolved": "https://registry.npmjs.org/mocha/-/mocha-3.5.3.tgz",
+          "integrity": "sha512-/6na001MJWEtYxHOV1WLfsmR4YIynkUEhBwzsb+fk2qmQ3iqsi258l/Q2MWHJMImAcNpZ8DEdYAK72NHoIQ9Eg==",
           "dev": true,
           "requires": {
             "browser-stdout": "1.3.0",
@@ -5333,6 +5339,7 @@
             "escape-string-regexp": "1.0.5",
             "glob": "7.1.1",
             "growl": "1.9.2",
+            "he": "1.1.1",
             "json3": "3.3.2",
             "lodash.create": "3.1.1",
             "mkdirp": "0.5.1",
@@ -5340,9 +5347,9 @@
           }
         },
         "solc": {
-          "version": "0.4.13",
-          "resolved": "https://registry.npmjs.org/solc/-/solc-0.4.13.tgz",
-          "integrity": "sha1-qly9zOPmrjwZDSD1/fi8iAcC7HU=",
+          "version": "0.4.18",
+          "resolved": "https://registry.npmjs.org/solc/-/solc-0.4.18.tgz",
+          "integrity": "sha512-Kq+O3PNF9Pfq7fB+lDYAuoqRdghLmZyfngsg0h1Hj38NKAeVHeGPOGeZasn5KqdPeCzbMFvaGyTySxzGv6aXCg==",
           "dev": true,
           "requires": {
             "fs-extra": "0.30.0",
@@ -5360,28 +5367,6 @@
           "requires": {
             "has-flag": "1.0.0"
           }
-        },
-        "yargs": {
-          "version": "4.8.1",
-          "resolved": "https://registry.npmjs.org/yargs/-/yargs-4.8.1.tgz",
-          "integrity": "sha1-wMQpJMpKqmsObaFznfshZDn53cA=",
-          "dev": true,
-          "requires": {
-            "cliui": "3.2.0",
-            "decamelize": "1.2.0",
-            "get-caller-file": "1.0.2",
-            "lodash.assign": "4.2.0",
-            "os-locale": "1.4.0",
-            "read-pkg-up": "1.0.1",
-            "require-directory": "2.1.1",
-            "require-main-filename": "1.0.1",
-            "set-blocking": "2.0.0",
-            "string-width": "1.0.2",
-            "which-module": "1.0.0",
-            "window-size": "0.2.0",
-            "y18n": "3.2.1",
-            "yargs-parser": "2.4.1"
-          }
         }
       }
     },
@@ -6019,6 +6004,28 @@
       "integrity": "sha1-HBH5IY8HYImkfdUS+TxmmaaoHVI=",
       "dev": true
     },
+    "yargs": {
+      "version": "4.8.1",
+      "resolved": "https://registry.npmjs.org/yargs/-/yargs-4.8.1.tgz",
+      "integrity": "sha1-wMQpJMpKqmsObaFznfshZDn53cA=",
+      "dev": true,
+      "requires": {
+        "cliui": "3.2.0",
+        "decamelize": "1.2.0",
+        "get-caller-file": "1.0.2",
+        "lodash.assign": "4.2.0",
+        "os-locale": "1.4.0",
+        "read-pkg-up": "1.0.1",
+        "require-directory": "2.1.1",
+        "require-main-filename": "1.0.1",
+        "set-blocking": "2.0.0",
+        "string-width": "1.0.2",
+        "which-module": "1.0.0",
+        "window-size": "0.2.0",
+        "y18n": "3.2.1",
+        "yargs-parser": "2.4.1"
+      }
+    },
     "yargs-parser": {
       "version": "2.4.1",
       "resolved": "https://registry.npmjs.org/yargs-parser/-/yargs-parser-2.4.1.tgz",
diff --git a/package.json b/package.json
index f980f9cabbe..74558d8f0c5 100644
--- a/package.json
+++ b/package.json
@@ -39,7 +39,7 @@
     "ethereumjs-testrpc": "^4.1.1",
     "mocha-lcov-reporter": "^1.3.0",
     "solidity-coverage": "^0.2.2",
-    "truffle": "^3.4.6",
+    "truffle": "^4.0.0",
     "truffle-hdwallet-provider": "0.0.3"
   }
 }
diff --git a/scripts/test.sh b/scripts/test.sh
index 7893fbe4688..044a7e01e2a 100755
--- a/scripts/test.sh
+++ b/scripts/test.sh
@@ -41,7 +41,7 @@ start_testrpc() {
   if [ "$SOLIDITY_COVERAGE" = true ]; then
     node_modules/.bin/testrpc-sc --gasLimit 0xfffffffffff --port "$testrpc_port" "${accounts[@]}" > /dev/null &
   else
-    node_modules/.bin/testrpc "${accounts[@]}" > /dev/null &
+    node_modules/.bin/testrpc --gasLimit 0xfffffffffff "${accounts[@]}" > /dev/null &
   fi
 
   testrpc_pid=$!
diff --git a/test/helpers/BasicTokenMock.sol b/test/helpers/BasicTokenMock.sol
index f1a0265f07b..6c3f8ef6912 100644
--- a/test/helpers/BasicTokenMock.sol
+++ b/test/helpers/BasicTokenMock.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 
 import '../../contracts/token/BasicToken.sol';
diff --git a/test/helpers/BurnableTokenMock.sol b/test/helpers/BurnableTokenMock.sol
index c82a0cac88a..ce6bb4c7cd8 100644
--- a/test/helpers/BurnableTokenMock.sol
+++ b/test/helpers/BurnableTokenMock.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.13;
+pragma solidity ^0.4.18;
 
 import '../../contracts/token/BurnableToken.sol';
 
diff --git a/test/helpers/CappedCrowdsaleImpl.sol b/test/helpers/CappedCrowdsaleImpl.sol
index 0f65471d08a..3c9692ed8ab 100644
--- a/test/helpers/CappedCrowdsaleImpl.sol
+++ b/test/helpers/CappedCrowdsaleImpl.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 
 import '../../contracts/crowdsale/CappedCrowdsale.sol';
diff --git a/test/helpers/DayLimitMock.sol b/test/helpers/DayLimitMock.sol
index 636b5394ff7..83accc7a5a8 100644
--- a/test/helpers/DayLimitMock.sol
+++ b/test/helpers/DayLimitMock.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 import "../../contracts/DayLimit.sol";
 
 contract DayLimitMock is DayLimit {
diff --git a/test/helpers/DetailedERC20Mock.sol b/test/helpers/DetailedERC20Mock.sol
index 5396ee4eff0..f1f5cbaca1f 100644
--- a/test/helpers/DetailedERC20Mock.sol
+++ b/test/helpers/DetailedERC20Mock.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 import '../../contracts/token/StandardToken.sol';
 import '../../contracts/token/DetailedERC20.sol';
diff --git a/test/helpers/ERC23TokenMock.sol b/test/helpers/ERC23TokenMock.sol
index 5773e3f5628..b06adffdc33 100644
--- a/test/helpers/ERC23TokenMock.sol
+++ b/test/helpers/ERC23TokenMock.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 
 import '../../contracts/token/BasicToken.sol';
diff --git a/test/helpers/FinalizableCrowdsaleImpl.sol b/test/helpers/FinalizableCrowdsaleImpl.sol
index 3c3279c1b14..c16ab463494 100644
--- a/test/helpers/FinalizableCrowdsaleImpl.sol
+++ b/test/helpers/FinalizableCrowdsaleImpl.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 
 import '../../contracts/crowdsale/FinalizableCrowdsale.sol';
diff --git a/test/helpers/ForceEther.sol b/test/helpers/ForceEther.sol
index 4d25ac4a201..eed268f3cb7 100644
--- a/test/helpers/ForceEther.sol
+++ b/test/helpers/ForceEther.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 // @title Force Ether into a contract.
 // @notice  even
diff --git a/test/helpers/HasNoEtherTest.sol b/test/helpers/HasNoEtherTest.sol
index 9f320c06f9b..135e07d0412 100644
--- a/test/helpers/HasNoEtherTest.sol
+++ b/test/helpers/HasNoEtherTest.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 import "../../contracts/ownership/HasNoEther.sol";
 
diff --git a/test/helpers/InsecureTargetBounty.sol b/test/helpers/InsecureTargetBounty.sol
index 3ac46a24e0a..e39b90a01e0 100644
--- a/test/helpers/InsecureTargetBounty.sol
+++ b/test/helpers/InsecureTargetBounty.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 
 import {Bounty, Target} from "../../contracts/Bounty.sol";
diff --git a/test/helpers/LimitBalanceMock.sol b/test/helpers/LimitBalanceMock.sol
index d38914ecdba..2a1b7237549 100644
--- a/test/helpers/LimitBalanceMock.sol
+++ b/test/helpers/LimitBalanceMock.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 
 import '../../contracts/LimitBalance.sol';
diff --git a/test/helpers/PausableMock.sol b/test/helpers/PausableMock.sol
index 97a5f28eac3..59a6b3dd0c0 100644
--- a/test/helpers/PausableMock.sol
+++ b/test/helpers/PausableMock.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 
 import '../../contracts/lifecycle/Pausable.sol';
diff --git a/test/helpers/PausableTokenMock.sol b/test/helpers/PausableTokenMock.sol
index 360402151b9..54e2cee144e 100644
--- a/test/helpers/PausableTokenMock.sol
+++ b/test/helpers/PausableTokenMock.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 import '../../contracts/token/PausableToken.sol';
 
diff --git a/test/helpers/PullPaymentMock.sol b/test/helpers/PullPaymentMock.sol
index 99800e9463b..93689ed8a34 100644
--- a/test/helpers/PullPaymentMock.sol
+++ b/test/helpers/PullPaymentMock.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 
 import '../../contracts/payment/PullPayment.sol';
diff --git a/test/helpers/ReentrancyAttack.sol b/test/helpers/ReentrancyAttack.sol
index 37b5cffd72e..091392b0da3 100644
--- a/test/helpers/ReentrancyAttack.sol
+++ b/test/helpers/ReentrancyAttack.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 contract ReentrancyAttack {
 
diff --git a/test/helpers/ReentrancyMock.sol b/test/helpers/ReentrancyMock.sol
index 63162fd9288..ecf45fef4bb 100644
--- a/test/helpers/ReentrancyMock.sol
+++ b/test/helpers/ReentrancyMock.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 import '../../contracts/ReentrancyGuard.sol';
 import './ReentrancyAttack.sol';
diff --git a/test/helpers/RefundableCrowdsaleImpl.sol b/test/helpers/RefundableCrowdsaleImpl.sol
index 1dccc8d256f..f11200ff1e0 100644
--- a/test/helpers/RefundableCrowdsaleImpl.sol
+++ b/test/helpers/RefundableCrowdsaleImpl.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 
 import '../../contracts/crowdsale/RefundableCrowdsale.sol';
diff --git a/test/helpers/SafeERC20Helper.sol b/test/helpers/SafeERC20Helper.sol
index 693af093444..abe73fc68a9 100644
--- a/test/helpers/SafeERC20Helper.sol
+++ b/test/helpers/SafeERC20Helper.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 import '../../contracts/token/ERC20.sol';
 import '../../contracts/token/SafeERC20.sol';
diff --git a/test/helpers/SafeMathMock.sol b/test/helpers/SafeMathMock.sol
index 5a20aefe825..0b94fb926d2 100644
--- a/test/helpers/SafeMathMock.sol
+++ b/test/helpers/SafeMathMock.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 
 import '../../contracts/math/SafeMath.sol';
diff --git a/test/helpers/SecureTargetBounty.sol b/test/helpers/SecureTargetBounty.sol
index 1f370246fc5..0d80e9c1373 100644
--- a/test/helpers/SecureTargetBounty.sol
+++ b/test/helpers/SecureTargetBounty.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 
 import {Bounty, Target} from "../../contracts/Bounty.sol";
diff --git a/test/helpers/SplitPaymentMock.sol b/test/helpers/SplitPaymentMock.sol
index 0f347a2665b..6df502a4e96 100644
--- a/test/helpers/SplitPaymentMock.sol
+++ b/test/helpers/SplitPaymentMock.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 import '../../contracts/payment/SplitPayment.sol';
 
diff --git a/test/helpers/StandardTokenMock.sol b/test/helpers/StandardTokenMock.sol
index 6425d2f9ea5..2189edce850 100644
--- a/test/helpers/StandardTokenMock.sol
+++ b/test/helpers/StandardTokenMock.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.11;
+pragma solidity ^0.4.18;
 
 
 import '../../contracts/token/StandardToken.sol';