diff --git a/.circleci/config.yml b/.circleci/config.yml
index 6cce6f5c41..869881ada7 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -22,7 +22,7 @@ step_setup_global_packages: &step_setup_global_packages
       yarn run provision:token:contracts
 step_pull_solc_docker: &step_pull_solc_docker
     run:
-      name: "Pull solc 0.4.23 docker image"
+      name: "Pull solc docker image"
       command: docker pull ethereum/solc:0.4.23
 jobs:
   lint-and-unit-test:
diff --git a/.gitignore b/.gitignore
index 21dda6701f..bd45bdcbe0 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,8 +2,6 @@ node_modules
 parity-genesis.json
 contracts/Updated*
 contracts/IUpdated*
-contracts/Token.sol
-contracts/TokenAuthority.sol
 keys/*
 test-results.xml
 0
diff --git a/.solcover.js b/.solcover.js
index 7ea9b59cc0..cb711ba536 100644
--- a/.solcover.js
+++ b/.solcover.js
@@ -2,11 +2,10 @@ module.exports = {
     skipFiles: [
       'Migrations.sol',
       'EtherRouter.sol',
-      'gnosis',
-      'ERC20ExtendedToken.sol',
-      'PatriciaTree'
+      'PatriciaTree',
+      'ERC20ExtendedToken.sol'
     ],
-    compileCommand: '../node_modules/.bin/truffle compile',
+    compileCommand: 'yarn run provision:token:contracts:compile',
     testCommand: '../node_modules/.bin/truffle test --network coverage',
     testrpcOptions: `--port 8555 -i 1999 --acctKeys="./coverageEnv/ganache-accounts.json" --noVMErrorsOnRPCResponse --accounts 12`
 };
diff --git a/.soliumignore b/.soliumignore
index 59d7dfacc8..357f9ef2fe 100644
--- a/.soliumignore
+++ b/.soliumignore
@@ -2,9 +2,6 @@ node_modules
 helpers
 migrations
 test
-contracts/Migrations.sol
-contracts/Token.sol
-contracts/TokenAuthority.sol
-contracts/gnosis/MultiSigWallet.sol
 lib
-packages
\ No newline at end of file
+packages
+contracts/Migrations.sol
\ No newline at end of file
diff --git a/contracts/Colony.sol b/contracts/Colony.sol
index 3ed96b4ee5..eec75a4285 100755
--- a/contracts/Colony.sol
+++ b/contracts/Colony.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23 <0.5.0;
 pragma experimental ABIEncoderV2;
 
 import "./ColonyStorage.sol";
@@ -31,7 +30,7 @@ contract Colony is ColonyStorage, PatriciaTreeProofs {
 
   function setFounderRole(address _user) public stoppable auth {
     // To allow only one address to have founder role at a time, we have to remove current founder from their role
-    ColonyAuthority colonyAuthority = ColonyAuthority(authority);
+    ColonyAuthority colonyAuthority = ColonyAuthority(address(authority));
     colonyAuthority.setUserRole(msg.sender, FOUNDER_ROLE, false);
     colonyAuthority.setUserRole(_user, FOUNDER_ROLE, true);
 
@@ -39,20 +38,20 @@ contract Colony is ColonyStorage, PatriciaTreeProofs {
   }
 
   function setAdminRole(address _user) public stoppable auth {
-    ColonyAuthority(authority).setUserRole(_user, ADMIN_ROLE, true);
+    ColonyAuthority(address(authority)).setUserRole(_user, ADMIN_ROLE, true);
 
     emit ColonyAdminRoleSet(_user);
   }
 
   // Can only be called by the founder role.
   function removeAdminRole(address _user) public stoppable auth {
-    ColonyAuthority(authority).setUserRole(_user, ADMIN_ROLE, false);
+    ColonyAuthority(address(authority)).setUserRole(_user, ADMIN_ROLE, false);
 
     emit ColonyAdminRoleRemoved(_user);
   }
 
   function hasUserRole(address _user, uint8 _role) public view returns (bool) {
-    return ColonyAuthority(authority).hasUserRole(_user, _role);
+    return ColonyAuthority(address(authority)).hasUserRole(_user, _role);
   }
 
   function getColonyNetworkAddress() public view returns (address) {
@@ -69,7 +68,7 @@ contract Colony is ColonyStorage, PatriciaTreeProofs {
   }
 
   function getToken() public view returns (address) {
-    return token;
+    return address(token);
   }
 
   function initialiseColony(address _colonyNetworkAddress) public stoppable {
@@ -104,7 +103,7 @@ contract Colony is ColonyStorage, PatriciaTreeProofs {
     emit ColonyInitialised(_colonyNetworkAddress);
   }
 
-  function bootstrapColony(address[] _users, int[] _amounts) public
+  function bootstrapColony(address[] memory _users, int[] memory _amounts) public
   stoppable
   auth
   isInBootstrapPhase
@@ -132,12 +131,12 @@ contract Colony is ColonyStorage, PatriciaTreeProofs {
     // Only the colony Network can call this function
     require(msg.sender == colonyNetworkAddress, "colony-access-denied-only-network-allowed");
     // Function only valid on the Meta Colony
-    require(this == IColonyNetwork(colonyNetworkAddress).getMetaColony(), "colony-access-denied-only-meta-colony-allowed");
+    require(address(this) == IColonyNetwork(colonyNetworkAddress).getMetaColony(), "colony-access-denied-only-meta-colony-allowed");
     token.mint(_wad);
     token.transfer(colonyNetworkAddress, _wad);
   }
 
-  function registerColonyLabel(string colonyName, string orbitdb) public stoppable auth {
+  function registerColonyLabel(string memory colonyName, string memory orbitdb) public stoppable auth {
     IColonyNetwork(colonyNetworkAddress).registerColonyLabel(colonyName, orbitdb);
   }
 
@@ -184,7 +183,7 @@ contract Colony is ColonyStorage, PatriciaTreeProofs {
     initialiseDomain(newLocalSkill);
   }
 
-  function getDomain(uint256 _id) public view returns (Domain domain) {
+  function getDomain(uint256 _id) public view returns (Domain memory domain) {
     domain = domains[_id];
   }
 
@@ -192,7 +191,7 @@ contract Colony is ColonyStorage, PatriciaTreeProofs {
     return domainCount;
   }
 
-  modifier verifyKey(bytes key) {
+  modifier verifyKey(bytes memory key) {
     uint256 colonyAddress;
     uint256 skillid;
     uint256 userAddress;
@@ -209,7 +208,7 @@ contract Colony is ColonyStorage, PatriciaTreeProofs {
     _;
   }
 
-  function verifyReputationProof(bytes key, bytes value, uint branchMask, bytes32[] siblings)  // solium-disable-line security/no-assign-params
+  function verifyReputationProof(bytes memory key, bytes memory value, uint branchMask, bytes32[] memory siblings)
   public view
   stoppable
   verifyKey(key)
@@ -228,9 +227,9 @@ contract Colony is ColonyStorage, PatriciaTreeProofs {
     require(_newVersion > currentVersion, "colony-version-must-be-newer");
     // Requested version has to be registered
     address newResolver = IColonyNetwork(colonyNetworkAddress).getColonyVersionResolver(_newVersion);
-    require(newResolver != 0x0, "colony-version-must-be-registered");
-    EtherRouter e = EtherRouter(address(this));
-    e.setResolver(newResolver);
+    require(newResolver != address(0x0), "colony-version-must-be-registered");
+    EtherRouter currentColony = EtherRouter(address(this));
+    currentColony.setResolver(newResolver);
 
     emit ColonyUpgraded(currentVersion, _newVersion);
   }
diff --git a/contracts/ColonyAuthority.sol b/contracts/ColonyAuthority.sol
index aa8033a70c..803d916c49 100644
--- a/contracts/ColonyAuthority.sol
+++ b/contracts/ColonyAuthority.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 
 import "./CommonAuthority.sol";
 
@@ -70,12 +69,12 @@ contract ColonyAuthority is CommonAuthority {
     setFounderRoleCapability(colony, "setAdminRole(address)");
   }
 
-  function setFounderRoleCapability(address colony, bytes sig) private {
+  function setFounderRoleCapability(address colony, bytes memory sig) private {
     bytes4 functionSig = bytes4(keccak256(sig));
     setRoleCapability(founderRole, colony, functionSig, true);
   }
 
-  function setAdminRoleCapability(address colony, bytes sig) private {
+  function setAdminRoleCapability(address colony, bytes memory sig) private {
     bytes4 functionSig = bytes4(keccak256(sig));
     setRoleCapability(adminRole, colony, functionSig, true);
   }
diff --git a/contracts/ColonyDataTypes.sol b/contracts/ColonyDataTypes.sol
index 2f31b65862..481138c480 100755
--- a/contracts/ColonyDataTypes.sol
+++ b/contracts/ColonyDataTypes.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 
 
 contract ColonyDataTypes {
diff --git a/contracts/ColonyFunding.sol b/contracts/ColonyFunding.sol
index 5226511c01..2cde7515e9 100755
--- a/contracts/ColonyFunding.sol
+++ b/contracts/ColonyFunding.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23 <0.5.0;
 pragma experimental "ABIEncoderV2";
 
 import "./ColonyStorage.sol";
@@ -52,8 +51,15 @@ contract ColonyFunding is ColonyStorage, PatriciaTreeProofs {
   {
     Task storage task = tasks[_id];
 
-    require(task.roles[EVALUATOR].user == task.roles[MANAGER].user || task.roles[EVALUATOR].user == 0x0, "colony-funding-evaluator-already-set");
-    require(task.roles[WORKER].user == task.roles[MANAGER].user || task.roles[WORKER].user == 0x0, "colony-funding-worker-already-set");
+    require(
+      task.roles[EVALUATOR].user == task.roles[MANAGER].user ||
+      task.roles[EVALUATOR].user == address(0x0),
+      "colony-funding-evaluator-already-set");
+
+    require(
+      task.roles[WORKER].user == task.roles[MANAGER].user ||
+      task.roles[WORKER].user == address(0x0),
+      "colony-funding-worker-already-set");
 
     this.setTaskManagerPayout(_id, _token, _managerAmount);
     this.setTaskEvaluatorPayout(_id, _token, _evaluatorAmount);
@@ -95,10 +101,9 @@ contract ColonyFunding is ColonyStorage, PatriciaTreeProofs {
     uint fee = calculateNetworkFeeForPayout(payout);
     uint remainder = sub(payout, fee);
 
-    if (_token == 0x0) {
+    if (_token == address(0x0)) {
       // Payout ether
-      address user = task.roles[_role].user;
-      user.transfer(remainder);
+      msg.sender.transfer(remainder);
       // Fee goes directly to Meta Colony
       IColonyNetwork colonyNetworkContract = IColonyNetwork(colonyNetworkAddress);
       address metaColonyAddress = colonyNetworkContract.getMetaColony();
@@ -169,13 +174,13 @@ contract ColonyFunding is ColonyStorage, PatriciaTreeProofs {
     uint toClaim;
     uint feeToPay;
     uint remainder;
-    if (_token == 0x0) {
+    if (_token == address(0x0)) {
       // It's ether
       toClaim = sub(sub(address(this).balance, nonRewardPotsTotal[_token]), pots[0].balance[_token]);
     } else {
       // Assume it's an ERC 20 token.
       ERC20Extended targetToken = ERC20Extended(_token);
-      toClaim = sub(sub(targetToken.balanceOf(this), nonRewardPotsTotal[_token]), pots[0].balance[_token]);
+      toClaim = sub(sub(targetToken.balanceOf(address(this)), nonRewardPotsTotal[_token]), pots[0].balance[_token]);
     }
 
     feeToPay = toClaim / getRewardInverse();
@@ -191,7 +196,9 @@ contract ColonyFunding is ColonyStorage, PatriciaTreeProofs {
     return nonRewardPotsTotal[_token];
   }
 
-  function startNextRewardPayout(address _token, bytes key, bytes value, uint256 branchMask, bytes32[] siblings) public auth stoppable {
+  function startNextRewardPayout(address _token, bytes memory key, bytes memory value, uint256 branchMask, bytes32[] memory siblings)
+  public auth stoppable 
+  {
     ITokenLocking tokenLocking = ITokenLocking(IColonyNetwork(colonyNetworkAddress).getTokenLocking());
     uint256 totalLockCount = tokenLocking.lockToken(address(token));
 
@@ -204,7 +211,7 @@ contract ColonyFunding is ColonyStorage, PatriciaTreeProofs {
     uint256 colonyWideReputation = checkReputation(
       rootHash,
       domains[1].skillId,
-      0x0,
+      address(0x0),
       key,
       value,
       branchMask,
@@ -228,11 +235,11 @@ contract ColonyFunding is ColonyStorage, PatriciaTreeProofs {
 
   function claimRewardPayout(
     uint256 _payoutId,
-    uint256[7] _squareRoots,
-    bytes key,
-    bytes value,
+    uint256[7] memory _squareRoots,
+    bytes memory key,
+    bytes memory value,
     uint256 branchMask,
-    bytes32[] siblings
+    bytes32[] memory siblings
   ) public stoppable
   {
     uint256 userReputation = checkReputation(
@@ -271,7 +278,7 @@ contract ColonyFunding is ColonyStorage, PatriciaTreeProofs {
     emit RewardPayoutCycleEnded(_payoutId);
   }
 
-  function getRewardPayoutInfo(uint256 _payoutId) public view returns (RewardPayoutCycle rewardPayoutCycle) {
+  function getRewardPayoutInfo(uint256 _payoutId) public view returns (RewardPayoutCycle memory rewardPayoutCycle) {
     rewardPayoutCycle = rewardPayoutCycles[_payoutId];
   }
 
@@ -293,10 +300,10 @@ contract ColonyFunding is ColonyStorage, PatriciaTreeProofs {
     bytes32 rootHash,
     uint256 skillId,
     address userAddress,
-    bytes key,
-    bytes value,
+    bytes memory key,
+    bytes memory value,
     uint256 branchMask,
-    bytes32[] siblings
+    bytes32[] memory siblings
   ) internal view returns (uint256)
   {
     bytes32 impliedRoot = getImpliedRootHashKey(key, value, branchMask, siblings);
@@ -321,7 +328,7 @@ contract ColonyFunding is ColonyStorage, PatriciaTreeProofs {
     return reputationValue;
   }
 
-  function calculateRewardForUser(uint256 payoutId, uint256[7] squareRoots, uint256 userReputation) internal returns (address, uint256) {
+  function calculateRewardForUser(uint256 payoutId, uint256[7] memory squareRoots, uint256 userReputation) internal returns (address, uint256) {
     RewardPayoutCycle memory payout = rewardPayoutCycles[payoutId];
     // Checking if payout is active
     require(block.timestamp - payout.blockTimestamp <= 60 days, "colony-reward-payout-not-active");
diff --git a/contracts/ColonyNetwork.sol b/contracts/ColonyNetwork.sol
index 07d565a6de..ce1ac36bdf 100644
--- a/contracts/ColonyNetwork.sol
+++ b/contracts/ColonyNetwork.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23 <0.5.0;
 pragma experimental "ABIEncoderV2";
 
 import "./ColonyAuthority.sol";
@@ -71,7 +70,7 @@ contract ColonyNetwork is ColonyNetworkStorage {
     return colonyVersionResolver[_version];
   }
 
-  function getSkill(uint256 _skillId) public view returns (Skill skill) {
+  function getSkill(uint256 _skillId) public view returns (Skill memory skill) {
     skill = skills[_skillId];
   }
 
@@ -96,7 +95,7 @@ contract ColonyNetwork is ColonyNetworkStorage {
   auth
   {
     // Token locking address can't be changed
-    require(tokenLocking == 0x0, "colony-invalid-token-locking-address");
+    require(tokenLocking == address(0x0), "colony-invalid-token-locking-address");
     tokenLocking = _tokenLocking;
 
     emit TokenLockingAddressSet(_tokenLocking);
@@ -123,7 +122,7 @@ contract ColonyNetwork is ColonyNetworkStorage {
   stoppable
   auth
   {
-    require(metaColony == 0, "colony-meta-colony-exists-already");
+    require(metaColony == address(0x0), "colony-meta-colony-exists-already");
     // Add the root global skill
     skillCount += 1;
     Skill memory rootGlobalSkill;
@@ -145,34 +144,33 @@ contract ColonyNetwork is ColonyNetworkStorage {
   {
     require(currentColonyVersion > 0, "colony-network-not-initialised-cannot-create-colony");
     EtherRouter etherRouter = new EtherRouter();
+    IColony colony = IColony(address(etherRouter));
     address resolverForLatestColonyVersion = colonyVersionResolver[currentColonyVersion];
     etherRouter.setResolver(resolverForLatestColonyVersion);
-
-    IColony colony = IColony(etherRouter);
     colony.setToken(_tokenAddress);
 
     // Creating new instance of colony's authority
-    ColonyAuthority authority = new ColonyAuthority(colony);
+    ColonyAuthority authority = new ColonyAuthority(address(colony));
 
     DSAuth dsauth = DSAuth(etherRouter);
     dsauth.setAuthority(authority);
 
-    authority.setOwner(etherRouter);
+    authority.setOwner(address(etherRouter));
     colony.setFounderRole(msg.sender);
 
     // Colony will not have owner
-    dsauth.setOwner(0x0);
+    dsauth.setOwner(address(0x0));
 
     // Initialise the root (domain) local skill with defaults by just incrementing the skillCount
     skillCount += 1;
     colonyCount += 1;
-    colonies[colonyCount] = colony;
-    _isColony[colony] = true;
+    colonies[colonyCount] = address(colony);
+    _isColony[address(colony)] = true;
 
-    colony.initialiseColony(this);
-    emit ColonyAdded(colonyCount, etherRouter, _tokenAddress);
+    colony.initialiseColony(address(this));
+    emit ColonyAdded(colonyCount, address(etherRouter), _tokenAddress);
 
-    return etherRouter;
+    return address(etherRouter);
   }
 
   function addColonyVersion(uint _version, address _resolver) public
diff --git a/contracts/ColonyNetworkAuction.sol b/contracts/ColonyNetworkAuction.sol
index 9af719dba6..985e6ee75a 100644
--- a/contracts/ColonyNetworkAuction.sol
+++ b/contracts/ColonyNetworkAuction.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23 <0.5.0;
 
 import "./ColonyNetworkStorage.sol";
 
@@ -24,15 +23,15 @@ import "./ColonyNetworkStorage.sol";
 contract ColonyNetworkAuction is ColonyNetworkStorage {
 
   function startTokenAuction(address _token) public stoppable {
-    require(_token != 0x0, "colony-auction-invalid-token");
+    require(_token != address(0x0), "colony-auction-invalid-token");
 
     uint lastAuctionTimestamp = recentAuctions[_token];
     require(lastAuctionTimestamp == 0 || now - lastAuctionTimestamp >= 30 days, "colony-auction-start-too-soon");
 
     address clny = IMetaColony(metaColony).getToken();
-    require(clny != 0x0, "colony-auction-invalid-clny-token");
+    require(clny != address(0x0), "colony-auction-invalid-clny-token");
 
-    uint availableTokens = ERC20Extended(_token).balanceOf(this);
+    uint availableTokens = ERC20Extended(_token).balanceOf(address(this));
 
     if (_token==clny) {
       // We don't auction CLNY. We just burn it instead.
@@ -42,7 +41,7 @@ contract ColonyNetworkAuction is ColonyNetworkStorage {
     }
 
     DutchAuction auction = new DutchAuction(clny, _token, metaColony);
-    ERC20Extended(_token).transfer(auction, availableTokens);
+    ERC20Extended(_token).transfer(address(auction), availableTokens);
     auction.start();
     recentAuctions[_token] = now;
     emit AuctionCreated(address(auction), _token, availableTokens);
@@ -122,7 +121,7 @@ contract DutchAuction is DSMath {
   function start() public
   auctionNotStarted
   {
-    quantity = token.balanceOf(this);
+    quantity = token.balanceOf(address(this));
     assert(quantity > 0);
 
     // Set the minimum price as such that it doesn't cause the finalPrice to be 0
@@ -174,7 +173,7 @@ contract DutchAuction is DSMath {
       bidCount += 1;
     }
 
-    clnyToken.transferFrom(msg.sender, this, amount);
+    clnyToken.transferFrom(msg.sender, address(this), amount);
     bids[msg.sender] = add(bids[msg.sender], amount);
     receivedTotal = add(receivedTotal, amount);
 
@@ -219,11 +218,11 @@ contract DutchAuction is DSMath {
   allBidsClaimed
   {
     // Transfer token remainder to the network
-    uint auctionTokenBalance = token.balanceOf(this);
+    uint auctionTokenBalance = token.balanceOf(address(this));
     token.transfer(colonyNetwork, auctionTokenBalance);
     // Check this contract balances in the working tokens is 0 before we kill it
-    assert(clnyToken.balanceOf(this) == 0);
-    assert(token.balanceOf(this) == 0);
+    assert(clnyToken.balanceOf(address(this)) == 0);
+    assert(token.balanceOf(address(this)) == 0);
     selfdestruct(colonyNetwork);
   }
 }
diff --git a/contracts/ColonyNetworkAuthority.sol b/contracts/ColonyNetworkAuthority.sol
index d1a66014f8..4488acc894 100644
--- a/contracts/ColonyNetworkAuthority.sol
+++ b/contracts/ColonyNetworkAuthority.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 
 import "./CommonAuthority.sol";
 
diff --git a/contracts/ColonyNetworkDataTypes.sol b/contracts/ColonyNetworkDataTypes.sol
index e843c75d7a..a893d7d621 100755
--- a/contracts/ColonyNetworkDataTypes.sol
+++ b/contracts/ColonyNetworkDataTypes.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 
 
 contract ColonyNetworkDataTypes {
diff --git a/contracts/ColonyNetworkENS.sol b/contracts/ColonyNetworkENS.sol
index 269674ae8b..c5bbddacc0 100644
--- a/contracts/ColonyNetworkENS.sol
+++ b/contracts/ColonyNetworkENS.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 
 import "./ens/ENS.sol";
 import "./ColonyNetworkStorage.sol";
@@ -30,9 +29,9 @@ contract ColonyNetworkENS is ColonyNetworkStorage {
   bytes32 constant USER_HASH = keccak256("user");
   bytes32 constant COLONY_HASH = keccak256("colony");
 
-  modifier unowned(bytes32 node, string domainName) {
+  modifier unowned(bytes32 node, string memory domainName) {
     address currentOwner = ENS(ens).owner(keccak256(abi.encodePacked(node, keccak256(abi.encodePacked(domainName)))));
-    require(currentOwner == 0, "colony-label-already-owned");
+    require(currentOwner == address(0x0), "colony-label-already-owned");
     _;
   }
 
@@ -49,11 +48,11 @@ contract ColonyNetworkENS is ColonyNetworkStorage {
     rootNode = _rootNode;
     userNode = keccak256(abi.encodePacked(rootNode, USER_HASH));
     colonyNode = keccak256(abi.encodePacked(rootNode, COLONY_HASH));
-    ENS(ens).setSubnodeOwner(rootNode, USER_HASH, this);
-    ENS(ens).setSubnodeOwner(rootNode, COLONY_HASH, this);
+    ENS(ens).setSubnodeOwner(rootNode, USER_HASH, address(this));
+    ENS(ens).setSubnodeOwner(rootNode, COLONY_HASH, address(this));
   }
 
-  function registerUserLabel(string username, string orbitdb)
+  function registerUserLabel(string memory username, string memory orbitdb)
   public
   stoppable
   // NB there is no way to call this as a colony yet - this is just future proofing us once there is
@@ -63,16 +62,16 @@ contract ColonyNetworkENS is ColonyNetworkStorage {
     require(bytes(username).length > 0, "colony-user-label-invalid");
     require(bytes(userLabels[msg.sender]).length == 0, "colony-user-label-already-owned");
     bytes32 subnode = keccak256(abi.encodePacked(username));
-    ENS(ens).setSubnodeOwner(userNode, subnode, this);
+    ENS(ens).setSubnodeOwner(userNode, subnode, address(this));
     bytes32 node = keccak256(abi.encodePacked(userNode, subnode));
-    ENS(ens).setResolver(node, this);
+    ENS(ens).setResolver(node, address(this));
     records[node].addr = msg.sender;
     records[node].orbitdb = orbitdb;
     userLabels[msg.sender] = username;
     emit UserLabelRegistered(msg.sender, subnode);
   }
 
-  function registerColonyLabel(string colonyName, string orbitdb)
+  function registerColonyLabel(string memory colonyName, string memory orbitdb)
   public
   calledByColony
   unowned(colonyNode, colonyName)
@@ -82,20 +81,20 @@ contract ColonyNetworkENS is ColonyNetworkStorage {
     require(bytes(colonyLabels[msg.sender]).length == 0, "colony-already-labeled");
     bytes32 subnode = keccak256(abi.encodePacked(colonyName));
 
-    ENS(ens).setSubnodeOwner(colonyNode, subnode, this);
+    ENS(ens).setSubnodeOwner(colonyNode, subnode, address(this));
     bytes32 node = keccak256(abi.encodePacked(colonyNode, subnode));
-    ENS(ens).setResolver(node, this);
+    ENS(ens).setResolver(node, address(this));
     records[node].addr = msg.sender;
     records[node].orbitdb = orbitdb;
     colonyLabels[msg.sender] = colonyName;
     emit ColonyLabelRegistered(msg.sender, subnode);
   }
 
-  function getProfileDBAddress(bytes32 node) public view returns (string) {
+  function getProfileDBAddress(bytes32 node) public view returns (string memory orbitDB) {
     return records[node].orbitdb;
   }
 
-  function lookupRegisteredENSDomain(address addr) public view returns(string) {
+  function lookupRegisteredENSDomain(address addr) public view returns(string memory domain) {
     if (bytes(userLabels[addr]).length != 0) {
       return string(abi.encodePacked(userLabels[addr], ".user.joincolony.eth"));
     } else if (bytes(colonyLabels[addr]).length != 0) {
diff --git a/contracts/ColonyNetworkMining.sol b/contracts/ColonyNetworkMining.sol
index 8694a56c95..25ad9222e3 100644
--- a/contracts/ColonyNetworkMining.sol
+++ b/contracts/ColonyNetworkMining.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 pragma experimental "ABIEncoderV2";
 
 import "./ColonyNetworkStorage.sol";
@@ -58,7 +57,7 @@ contract ColonyNetworkMining is ColonyNetworkStorage {
   }
 
   function getReplacementReputationUpdateLogEntry(address _reputationMiningCycle, uint256 _id) public view returns
-    (ReputationLogEntry reputationLogEntry)
+    (ReputationLogEntry memory reputationLogEntry)
     {
     reputationLogEntry = replacementReputationUpdateLog[_reputationMiningCycle][_id];
   }
@@ -67,14 +66,14 @@ contract ColonyNetworkMining is ColonyNetworkStorage {
     return replacementReputationUpdateLogsExist[_reputationMiningCycle];
   }
 
-  function setReputationRootHash(bytes32 newHash, uint256 newNNodes, address[] stakers, uint256 reward) public
+  function setReputationRootHash(bytes32 newHash, uint256 newNNodes, address[] memory stakers, uint256 reward) public
   stoppable
   onlyReputationMiningCycle
   {
     reputationRootHash = newHash;
     reputationRootHashNNodes = newNNodes;
     // Reward stakers
-    activeReputationMiningCycle = 0x0;
+    activeReputationMiningCycle = address(0x0);
     startNextCycle();
     rewardStakers(stakers, reward);
 
@@ -82,12 +81,13 @@ contract ColonyNetworkMining is ColonyNetworkStorage {
   }
 
   function initialiseReputationMining() public stoppable {
-    require(inactiveReputationMiningCycle == 0x0, "colony-reputation-mining-already-initialised");
+    require(inactiveReputationMiningCycle == address(0x0), "colony-reputation-mining-already-initialised");
     address clnyToken = IMetaColony(metaColony).getToken();
-    require(clnyToken != 0x0, "colony-reputation-mining-clny-token-invalid-address");
+    require(clnyToken != address(0x0), "colony-reputation-mining-clny-token-invalid-address");
 
-    inactiveReputationMiningCycle = new EtherRouter();
-    EtherRouter(inactiveReputationMiningCycle).setResolver(miningCycleResolver);
+    EtherRouter e = new EtherRouter();
+    e.setResolver(miningCycleResolver);
+    inactiveReputationMiningCycle = address(e);
     IReputationMiningCycle(inactiveReputationMiningCycle).initialise(tokenLocking, clnyToken);
 
     emit ReputationMiningInitialised(inactiveReputationMiningCycle);
@@ -95,15 +95,16 @@ contract ColonyNetworkMining is ColonyNetworkStorage {
 
   function startNextCycle() public stoppable {
     address clnyToken = IMetaColony(metaColony).getToken();
-    require(clnyToken != 0x0, "colony-reputation-mining-clny-token-invalid-address");
-    require(activeReputationMiningCycle == 0x0, "colony-reputation-mining-still-active");
-    require(inactiveReputationMiningCycle != 0x0, "colony-reputation-mining-not-initialised");
+    require(clnyToken != address(0x0), "colony-reputation-mining-clny-token-invalid-address");
+    require(activeReputationMiningCycle == address(0x0), "colony-reputation-mining-still-active");
+    require(inactiveReputationMiningCycle != address(0x0), "colony-reputation-mining-not-initialised");
     // Inactive now becomes active
     activeReputationMiningCycle = inactiveReputationMiningCycle;
     IReputationMiningCycle(activeReputationMiningCycle).resetWindow();
 
-    inactiveReputationMiningCycle = new EtherRouter();
-    EtherRouter(inactiveReputationMiningCycle).setResolver(miningCycleResolver);
+    EtherRouter e = new EtherRouter();
+    e.setResolver(miningCycleResolver);
+    inactiveReputationMiningCycle = address(e);
     IReputationMiningCycle(inactiveReputationMiningCycle).initialise(tokenLocking, clnyToken);
     emit ReputationMiningCycleComplete(reputationRootHash, reputationRootHashNNodes);
   }
@@ -134,7 +135,7 @@ contract ColonyNetworkMining is ColonyNetworkStorage {
     return wmul(stakeTerm, submissionTerm);
   }
 
-  function rewardStakers(address[] stakers, uint256 reward) internal {
+  function rewardStakers(address[] memory stakers, uint256 reward) internal {
     // Internal unlike punish, because it's only ever called from setReputationRootHash
 
     // Passing an array so that we don't incur the EtherRouter overhead for each staker if we looped over
diff --git a/contracts/ColonyNetworkStorage.sol b/contracts/ColonyNetworkStorage.sol
index e377fde742..75764c0ed2 100644
--- a/contracts/ColonyNetworkStorage.sol
+++ b/contracts/ColonyNetworkStorage.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23 <0.5.0;
 
 import "../lib/dappsys/math.sol";
 import "./ERC20Extended.sol";
diff --git a/contracts/ColonyStorage.sol b/contracts/ColonyStorage.sol
index 2d4497ccd9..42117b7b57 100755
--- a/contracts/ColonyStorage.sol
+++ b/contracts/ColonyStorage.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 
 import "../lib/dappsys/math.sol";
 import "./ERC20Extended.sol";
@@ -141,7 +140,7 @@ contract ColonyStorage is CommonStorage, ColonyDataTypes, DSMath {
   }
 
   modifier isAdmin(address _user) {
-    require(ColonyAuthority(authority).hasUserRole(_user, ADMIN_ROLE), "colony-not-admin");
+    require(ColonyAuthority(address(authority)).hasUserRole(_user, ADMIN_ROLE), "colony-not-admin");
     _;
   }
 
diff --git a/contracts/ColonyTask.sol b/contracts/ColonyTask.sol
index 580a64c25c..000ddcd5f8 100755
--- a/contracts/ColonyTask.sol
+++ b/contracts/ColonyTask.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 pragma experimental "ABIEncoderV2";
 
 import "./ColonyStorage.sol";
@@ -128,12 +127,12 @@ contract ColonyTask is ColonyStorage {
   }
 
   function executeTaskChange(
-    uint8[] _sigV,
-    bytes32[] _sigR,
-    bytes32[] _sigS,
-    uint8[] _mode,
+    uint8[] memory _sigV,
+    bytes32[] memory _sigR,
+    bytes32[] memory _sigS,
+    uint8[] memory _mode,
     uint256 _value,
-    bytes _data) public stoppable
+    bytes memory _data) public stoppable
   {
     require(_value == 0, "colony-task-change-non-zero-value");
     require(_sigR.length == _sigS.length && _sigR.length == _sigV.length, "colony-task-change-signatures-count-do-not-match");
@@ -187,12 +186,12 @@ contract ColonyTask is ColonyStorage {
   }
 
   function executeTaskRoleAssignment(
-    uint8[] _sigV,
-    bytes32[] _sigR,
-    bytes32[] _sigS,
-    uint8[] _mode,
+    uint8[] memory _sigV,
+    bytes32[] memory _sigR,
+    bytes32[] memory _sigS,
+    uint8[] memory _mode,
     uint256 _value,
-    bytes _data) public stoppable
+    bytes memory _data) public stoppable
   {
     require(_value == 0, "colony-task-role-assignment-non-zero-value");
     require(_sigR.length == _sigS.length && _sigR.length == _sigV.length, "colony-task-role-assignment-signatures-count-do-not-match");
@@ -296,22 +295,22 @@ contract ColonyTask is ColonyStorage {
 
   function setTaskEvaluatorRole(uint256 _id, address _user) public stoppable self {
     // Can only assign role if no one is currently assigned to it
-    require(tasks[_id].roles[EVALUATOR].user == 0x0, "colony-task-evaluator-role-already-assigned");
+    require(tasks[_id].roles[EVALUATOR].user == address(0x0), "colony-task-evaluator-role-already-assigned");
     setTaskRoleUser(_id, EVALUATOR, _user);
   }
 
   function setTaskWorkerRole(uint256 _id, address _user) public stoppable self {
     // Can only assign role if no one is currently assigned to it
-    require(tasks[_id].roles[WORKER].user == 0x0, "colony-task-worker-role-already-assigned");
+    require(tasks[_id].roles[WORKER].user == address(0x0), "colony-task-worker-role-already-assigned");
     setTaskRoleUser(_id, WORKER, _user);
   }
 
   function removeTaskEvaluatorRole(uint256 _id) public stoppable self {
-    setTaskRoleUser(_id, EVALUATOR, 0x0);
+    setTaskRoleUser(_id, EVALUATOR, address(0x0));
   }
 
   function removeTaskWorkerRole(uint256 _id) public stoppable self {
-    setTaskRoleUser(_id, WORKER, 0x0);
+    setTaskRoleUser(_id, WORKER, address(0x0));
   }
 
   function setTaskDomain(uint256 _id, uint256 _domainId) public
@@ -421,7 +420,7 @@ contract ColonyTask is ColonyStorage {
     emit TaskCanceled(_id);
   }
 
-  function getTask(uint256 _id) public view returns (bytes32, bytes32, uint8, uint256, uint256, uint256, uint256, uint256, uint256[]) {
+  function getTask(uint256 _id) public view returns (bytes32, bytes32, uint8, uint256, uint256, uint256, uint256, uint256, uint256[] memory) {
     Task storage t = tasks[_id];
     return (
       t.specificationHash,
@@ -436,7 +435,7 @@ contract ColonyTask is ColonyStorage {
     );
   }
 
-  function getTaskRole(uint256 _id, uint8 _role) public view returns (Role role) {
+  function getTaskRole(uint256 _id, uint8 _role) public view returns (Role memory role) {
     role = tasks[_id].roles[_role];
   }
 
@@ -453,7 +452,7 @@ contract ColonyTask is ColonyStorage {
       role.rating = role.rateFail ? TaskRatings.Unsatisfactory : TaskRatings.Satisfactory;
     }
 
-    uint256 payout = task.payouts[roleId][token];
+    uint256 payout = task.payouts[roleId][address(token)];
     int256 reputation = getReputation(payout, role.rating, role.rateFail);
 
     colonyNetworkContract.appendReputationUpdateLog(role.user, reputation, domains[task.domainId].skillId);
@@ -477,12 +476,12 @@ contract ColonyTask is ColonyStorage {
   }
 
   function getReviewerAddresses(
-    uint8[] _sigV,
-    bytes32[] _sigR,
-    bytes32[] _sigS,
-    uint8[] _mode,
+    uint8[] memory _sigV,
+    bytes32[] memory _sigR,
+    bytes32[] memory _sigS,
+    uint8[] memory _mode,
     bytes32 msgHash
-  ) internal pure returns (address[])
+  ) internal pure returns (address[] memory)
   {
     address[] memory reviewerAddresses = new address[](_sigR.length);
     for (uint i = 0; i < _sigR.length; i++) {
@@ -503,7 +502,7 @@ contract ColonyTask is ColonyStorage {
 
   // The address.call() syntax is no longer recommended, see:
   // https://github.com/ethereum/solidity/issues/2884
-  function executeCall(address to, uint256 value, bytes data) internal returns (bool success) {
+  function executeCall(address to, uint256 value, bytes memory data) internal returns (bool success) {
     assembly {
       success := call(gas, to, value, add(data, 0x20), mload(data), 0, 0)
       }
@@ -511,14 +510,14 @@ contract ColonyTask is ColonyStorage {
 
   // Get the function signature and task id from the transaction bytes data
   // Note: Relies on the encoded function's first parameter to be the uint256 taskId
-  function deconstructCall(bytes _data) internal pure returns (bytes4 sig, uint256 taskId) {
+  function deconstructCall(bytes memory _data) internal pure returns (bytes4 sig, uint256 taskId) {
     assembly {
       sig := mload(add(_data, 0x20))
       taskId := mload(add(_data, 0x24)) // same as calldataload(72)
     }
   }
 
-  function deconstructRoleChangeCall(bytes _data) internal pure returns (bytes4 sig, uint256 taskId, address userAddress) {
+  function deconstructRoleChangeCall(bytes memory _data) internal pure returns (bytes4 sig, uint256 taskId, address userAddress) {
     assembly {
       sig := mload(add(_data, 0x20))
       taskId := mload(add(_data, 0x24)) // same as calldataload(72)
diff --git a/contracts/CommonAuthority.sol b/contracts/CommonAuthority.sol
index 86b26a6f89..8e39b7803c 100644
--- a/contracts/CommonAuthority.sol
+++ b/contracts/CommonAuthority.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 
 import "../lib/dappsys/roles.sol";
 
@@ -31,7 +30,7 @@ contract CommonAuthority is DSRoles {
     setRecoveryRoleCapability(contractAddress, "exitRecoveryMode()");
   }
 
-  function setRecoveryRoleCapability(address contractAddress, bytes sig) private {
+  function setRecoveryRoleCapability(address contractAddress, bytes memory sig) private {
     bytes4 functionSig = bytes4(keccak256(sig));
     setRoleCapability(recoveryRole, contractAddress, functionSig, true);
   }
diff --git a/contracts/CommonStorage.sol b/contracts/CommonStorage.sol
index 98f28ad094..04496e9b97 100644
--- a/contracts/CommonStorage.sol
+++ b/contracts/CommonStorage.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 
 import "../lib/dappsys/auth.sol";
 
diff --git a/contracts/ContractEditing.sol b/contracts/ContractEditing.sol
index d8070500d7..a372c541c2 100644
--- a/contracts/ContractEditing.sol
+++ b/contracts/ContractEditing.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 
 
 contract ContractEditing {
diff --git a/contracts/ContractRecovery.sol b/contracts/ContractRecovery.sol
index ed29306662..1296bbc645 100644
--- a/contracts/ContractRecovery.sol
+++ b/contracts/ContractRecovery.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 
 import "./CommonStorage.sol";
 import "./CommonAuthority.sol";
@@ -33,7 +32,7 @@ contract ContractRecovery is CommonStorage {
     require(_slot != RESOLVER_SLOT, "colony-common-protected-variable");
 
     // NB. This isn't necessarily a colony - could be ColonyNetwork. But they both have this function, so it's okay.
-    IRecovery(this).checkNotAdditionalProtectedVariable(_slot);
+    IRecovery(address(this)).checkNotAdditionalProtectedVariable(_slot);
 
     // Protect key variables
     uint64 _recoveryRolesCount = recoveryRolesCount;
@@ -73,7 +72,7 @@ contract ContractRecovery is CommonStorage {
   function exitRecoveryMode() public recovery auth {
     uint totalAuthorized = recoveryRolesCount;
     // Don't double count the owner (if set);
-    if (owner != 0x0 && !CommonAuthority(authority).hasUserRole(owner, RECOVERY_ROLE)) { 
+    if (owner != address(0x0) && !CommonAuthority(address(authority)).hasUserRole(owner, RECOVERY_ROLE)) { 
       totalAuthorized += 1; 
     }
     uint numRequired = totalAuthorized / 2 + 1;
@@ -84,16 +83,16 @@ contract ContractRecovery is CommonStorage {
   // Can only be called by the founder role.
   function setRecoveryRole(address _user) public stoppable auth {
     require(recoveryRolesCount < ~uint64(0), "colony-maximum-num-recovery-roles");
-    if (!CommonAuthority(authority).hasUserRole(_user, RECOVERY_ROLE)) {
-      CommonAuthority(authority).setUserRole(_user, RECOVERY_ROLE, true);
+    if (!CommonAuthority(address(authority)).hasUserRole(_user, RECOVERY_ROLE)) {
+      CommonAuthority(address(authority)).setUserRole(_user, RECOVERY_ROLE, true);
       recoveryRolesCount++;
     }
   }
 
   // Can only be called by the founder role.
   function removeRecoveryRole(address _user) public stoppable auth {
-    if (CommonAuthority(authority).hasUserRole(_user, RECOVERY_ROLE)) {
-      CommonAuthority(authority).setUserRole(_user, RECOVERY_ROLE, false);
+    if (CommonAuthority(address(authority)).hasUserRole(_user, RECOVERY_ROLE)) {
+      CommonAuthority(address(authority)).setUserRole(_user, RECOVERY_ROLE, false);
       recoveryRolesCount--;
     }
   }
diff --git a/contracts/ERC20Extended.sol b/contracts/ERC20Extended.sol
index 6b7339e7ab..bc07fe1471 100644
--- a/contracts/ERC20Extended.sol
+++ b/contracts/ERC20Extended.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 
 import "../lib/dappsys/erc20.sol";
 
diff --git a/contracts/ERC20ExtendedToken.sol b/contracts/ERC20ExtendedToken.sol
index 47215b9026..da487a4681 100644
--- a/contracts/ERC20ExtendedToken.sol
+++ b/contracts/ERC20ExtendedToken.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 
 
 import "../lib/dappsys/auth.sol";
@@ -29,7 +28,7 @@ contract ERC20ExtendedToken is DSTokenBase(0), DSAuth, ERC20Extended {
   string public symbol;
   string public name;
 
-  constructor(string _name, string _symbol, uint8 _decimals) public {
+  constructor(string memory _name, string memory _symbol, uint8 _decimals) public {
     name = _name;
     symbol = _symbol;
     decimals = _decimals;
@@ -42,7 +41,7 @@ contract ERC20ExtendedToken is DSTokenBase(0), DSAuth, ERC20Extended {
     _supply = add(_supply, wad);
 
     emit Mint(msg.sender, wad);
-    emit Transfer(0x0, msg.sender, wad);
+    emit Transfer(address(0x0), msg.sender, wad);
   }
 
   function burn(uint wad) public {
diff --git a/contracts/EtherRouter.sol b/contracts/EtherRouter.sol
index ff7ad78a33..495225cdc2 100644
--- a/contracts/EtherRouter.sol
+++ b/contracts/EtherRouter.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 
 import "./Resolver.sol";
 import "../lib/dappsys/auth.sol";
@@ -26,7 +25,7 @@ contract EtherRouter is DSAuth {
   Resolver public resolver;
 
   function() external payable {
-    if (msg.sig == 0x0) {
+    if (msg.sig == 0) {
       return;
     }
     // Contracts that want to receive Ether with a plain "send" have to implement
diff --git a/contracts/IColony.sol b/contracts/IColony.sol
index 24f0a0f2c7..8d3b84ad0a 100644
--- a/contracts/IColony.sol
+++ b/contracts/IColony.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 pragma experimental ABIEncoderV2;
 
 import "./IRecovery.sol";
@@ -31,7 +30,7 @@ contract IColony is ColonyDataTypes, IRecovery {
   /// @return colonyAuthority The `ColonyAuthority` contract address
   function authority() public view returns (address colonyAuthority);
 
-  /// @notice Get the colony `owner` address. This should be 0x0 at all times
+  /// @notice Get the colony `owner` address. This should be address(0x0) at all times
   /// @dev Used for testing.
   /// @return colonyOwner Address of the colony owner
   function owner() public view returns (address colonyOwner);
@@ -95,7 +94,7 @@ contract IColony is ColonyDataTypes, IRecovery {
   /// @dev Only allowed to be called when `taskCount` is 0 by authorized addresses
   /// @param _users Array of address to bootstrap with reputation
   /// @param _amount Amount of reputation/tokens for every address
-  function bootstrapColony(address[] _users, int[] _amount) public;
+  function bootstrapColony(address[] memory _users, int[] memory _amount) public;
 
   /// @notice Mint `_wad` amount of colony tokens. Secured function to authorised members
   /// @param _wad Amount to mint
@@ -104,7 +103,7 @@ contract IColony is ColonyDataTypes, IRecovery {
   /// @notice Register colony's ENS label
   /// @param colonyName The label to register.
   /// @param orbitdb The path of the orbitDB database associated with the colony name
-  function registerColonyLabel(string colonyName, string orbitdb) public;
+  function registerColonyLabel(string memory colonyName, string memory orbitdb) public;
 
   /// @notice Add a colony domain, and its respective local skill under skill with id `_parentSkillId`
   /// New funding pot is created and associated with the domain here
@@ -115,7 +114,7 @@ contract IColony is ColonyDataTypes, IRecovery {
   /// @notice Get a domain by id
   /// @param _id Id of the domain which details to get
   /// @return domain The domain
-  function getDomain(uint256 _id) public view returns (Domain domain);
+  function getDomain(uint256 _id) public view returns (Domain memory domain);
 
   /// @notice Get the non-mapping properties of a pot by id
   /// @param _id Id of the pot which details to get
@@ -139,7 +138,8 @@ contract IColony is ColonyDataTypes, IRecovery {
   /// While public, likely only to be used by the Colony contracts, as it checks that the user is proving their own
   /// reputation in the current colony. The `verifyProof` function can be used to verify any proof, though this function
   /// is not currently exposed on the Colony's EtherRouter.
-  function verifyReputationProof(bytes key, bytes value, uint256 branchMask, bytes32[] siblings) public view returns (bool isValid);
+  function verifyReputationProof(bytes memory key, bytes memory value, uint256 branchMask, bytes32[] memory siblings)
+    public view returns (bool isValid);
 
   // Implemented in ColonyTask.sol
   /// @notice Make a new task in the colony. Secured function to authorised members
@@ -170,12 +170,12 @@ contract IColony is ColonyDataTypes, IRecovery {
   /// Currently we only accept 0 value transactions but this is kept as a future option
   /// @param _data The transaction data
   function executeTaskChange(
-    uint8[] _sigV,
-    bytes32[] _sigR,
-    bytes32[] _sigS,
-    uint8[] _mode,
+    uint8[] memory _sigV,
+    bytes32[] memory _sigR,
+    bytes32[] memory _sigS,
+    uint8[] memory _mode,
     uint256 _value,
-    bytes _data
+    bytes memory _data
     ) public;
 
   /// @notice Executes a task role update transaction `_data` which is approved and signed by two of addresses
@@ -189,12 +189,12 @@ contract IColony is ColonyDataTypes, IRecovery {
   /// Currently we only accept 0 value transactions but this is kept as a future option
   /// @param _data The transaction data
   function executeTaskRoleAssignment(
-    uint8[] _sigV,
-    bytes32[] _sigR,
-    bytes32[] _sigS,
-    uint8[] _mode,
+    uint8[] memory _sigV,
+    bytes32[] memory _sigR,
+    bytes32[] memory _sigS,
+    uint8[] memory _mode,
     uint256 _value,
-    bytes _data
+    bytes memory _data
     ) public;
 
   /// @notice Submit a hashed secret of the rating for work in task `_id` which was performed by user with task role id `_role`
@@ -346,14 +346,14 @@ contract IColony is ColonyDataTypes, IRecovery {
     uint256 potId,
     uint256 completionTimestamp,
     uint256 domainId,
-    uint256[] skillIds
+    uint256[] memory skillIds
     );
 
   /// @notice Get the `Role` properties back for role `_role` in task `_id`
   /// @param _id Id of the task
   /// @param _role Id of the role, as defined in `ColonyStorage` `MANAGER`, `EVALUATOR` and `WORKER` constants
   /// @return role The Role
-  function getTaskRole(uint256 _id, uint8 _role) public view returns (Role role);
+  function getTaskRole(uint256 _id, uint8 _role) public view returns (Role memory role);
 
   /// @notice Set the reward inverse to pay out from revenue. e.g. if the fee is 1% (or 0.01), set 100
   /// @param _rewardInverse The inverse of the reward
@@ -418,7 +418,7 @@ contract IColony is ColonyDataTypes, IRecovery {
   /// @param value Reputation value
   /// @param branchMask The branchmask of the proof
   /// @param siblings The siblings of the proof
-  function startNextRewardPayout(address _token, bytes key, bytes value, uint256 branchMask, bytes32[] siblings) public;
+  function startNextRewardPayout(address _token, bytes memory key, bytes memory value, uint256 branchMask, bytes32[] memory siblings) public;
 
   /// @notice Claim the reward payout at `_payoutId`. User needs to provide their reputation and colony-wide reputation
   /// which will be proven via Merkle proof inside this function.
@@ -439,14 +439,13 @@ contract IColony is ColonyDataTypes, IRecovery {
   /// @param siblings The siblings of the proof
   function claimRewardPayout(
     uint256 _payoutId,
-    uint256[7] _squareRoots,
-    bytes key,
-    bytes value,
+    uint256[7] memory _squareRoots,
+    bytes memory key,
+    bytes memory value,
     uint256 branchMask,
-    bytes32[] siblings
+    bytes32[] memory siblings
     ) public;
 
-
   /// @notice Get useful information about specific reward payout
   /// @param _payoutId Id of the reward payout
   /// @return RewardPayoutCycle, containing propertes:
@@ -456,7 +455,7 @@ contract IColony is ColonyDataTypes, IRecovery {
   ///  amount Total amount of tokens taken aside for reward payout
   ///  tokenAddress Token address
   ///  blockTimestamp Block number at the time of creation
-  function getRewardPayoutInfo(uint256 _payoutId) public view returns ( RewardPayoutCycle rewardPayoutCycle );
+  function getRewardPayoutInfo(uint256 _payoutId) public view returns (RewardPayoutCycle memory rewardPayoutCycle );
 
   /// @notice Finalises the reward payout. Allows creation of next reward payouts for token that has been used in `_payoutId`
   /// Can only be called when reward payout cycle is finished i.e when 60 days have passed from its creation
diff --git a/contracts/IColonyNetwork.sol b/contracts/IColonyNetwork.sol
index 16c057dc5a..b7ef34646d 100644
--- a/contracts/IColonyNetwork.sol
+++ b/contracts/IColonyNetwork.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23 <0.5.0;
 pragma experimental "ABIEncoderV2";
 
 import "./IRecovery.sol";
@@ -62,7 +61,7 @@ contract IColonyNetwork is ColonyNetworkDataTypes, IRecovery {
   /// @return (address, int256, uint256, address, uint256, uint256) An object with the details of the log entry (if it exists)
   /// @dev colonyAddress will always be set if the replacement exists
   function getReplacementReputationUpdateLogEntry(address _reputationMiningCycle, uint256 _id) public view returns
-    (ReputationLogEntry reputationLogEntry);
+    (ReputationLogEntry memory reputationLogEntry);
 
   /// @notice Get whether any replacement log entries have been set for the supplied reputation mining cycle.
   /// @notice Used by the client to avoid doubling the number of RPC calls when syncing from scratch.
@@ -71,7 +70,7 @@ contract IColonyNetwork is ColonyNetworkDataTypes, IRecovery {
 
   /// @notice Get the Meta Colony address
   /// @return colonyAddress The Meta colony address, if no colony was found, returns 0x0
-  function getMetaColony() public view returns (address colonyAddress);
+  function getMetaColony() public view returns (address);
 
   /// @notice Get the number of colonies in the network
   /// @return count The colony count
@@ -96,7 +95,7 @@ contract IColonyNetwork is ColonyNetworkDataTypes, IRecovery {
   /// @return nParents uint256 `skill.nParents` i.e. the number of parent skills of skill with id `_skillId`
   /// @return nChildren uint256 `skill.nChildren` i.e. the number of child skills of skill with id `_skillId`
   /// @return isGlobalSkill true if specified skill is a global skill, otherwise false
-  function getSkill(uint256 _skillId) public view returns (Skill skill);
+  function getSkill(uint256 _skillId) public view returns (Skill memory skill);
 
   /// @notice Get whether the skill with id _skillId is public or not.
   /// @return isGlobalSkill bool 
@@ -142,7 +141,7 @@ contract IColonyNetwork is ColonyNetworkDataTypes, IRecovery {
   /// Additionally token can optionally support `mint` as defined in `ERC20Extended`
   /// Support for `mint` in mandatory only for the Meta Colony Token
   /// @return colonyAddress Address of the newly created colony
-  function createColony(address _tokenAddress) public returns (address colonyAddress);
+  function createColony(address _tokenAddress) public returns (address);
 
   /// @notice Adds a new Colony contract version and the address of associated `_resolver` contract. Secured function to authorised members
   /// Allowed to be called by the Meta Colony only
@@ -199,7 +198,7 @@ contract IColonyNetwork is ColonyNetworkDataTypes, IRecovery {
   /// @param newNNodes The updated nodes count value
   /// @param stakers Array of users who submitted or backed the hash, being accepted here as the new reputation root hash
   /// @param reward Amount of CLNY to be distributed as reward to miners
-  function setReputationRootHash(bytes32 newHash, uint256 newNNodes, address[] stakers, uint256 reward) public;
+  function setReputationRootHash(bytes32 newHash, uint256 newNNodes, address[] memory stakers, uint256 reward) public;
 
   /// @notice Starts a new Reputation Mining cycle. Explicitly called only the first time,
   /// subsequently called from within `setReputationRootHash`
@@ -229,22 +228,22 @@ contract IColonyNetwork is ColonyNetworkDataTypes, IRecovery {
   /// @notice Register a "user.joincolony.eth" label.
   /// @param username The label to register
   /// @param orbitdb The path of the orbitDB database associated with the user profile
-  function registerUserLabel(string username, string orbitdb) public;
+  function registerUserLabel(string memory username, string memory orbitdb) public;
 
   /// @notice Register a "colony.joincolony.eth" label. Can only be called by a Colony.
   /// @param colonyName The label to register.
   /// @param orbitdb The path of the orbitDB database associated with the colony name
-  function registerColonyLabel(string colonyName, string orbitdb) public;
+  function registerColonyLabel(string memory colonyName, string memory orbitdb) public;
 
   /// @notice Retrieve the orbitdb address corresponding to a registered account
   /// @param node The Namehash of the account being queried.
   /// @return orbitDB A string containing the address of the orbit database
-  function getProfileDBAddress(bytes32 node) public view returns (string orbitDB);
+  function getProfileDBAddress(bytes32 node) public view returns (string memory orbitDB);
 
   /// @notice Reverse lookup a username from an address.
   /// @param addr The address we wish to find the corresponding ENS domain for (if any)
   /// @return domain A string containing the colony-based ENS name corresponding to addr
-  function lookupRegisteredENSDomain(address addr) public view returns(string domain);
+  function lookupRegisteredENSDomain(address addr) public view returns(string memory domain);
 
   /// @notice Returns the address the supplied node resolves do, if we are the resolver
   /// @param node The namehash of the ENS address being requested
diff --git a/contracts/IMetaColony.sol b/contracts/IMetaColony.sol
index 6b95230915..c96ed1b82c 100644
--- a/contracts/IMetaColony.sol
+++ b/contracts/IMetaColony.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 pragma experimental "ABIEncoderV2";
 
 import "./IColony.sol";
diff --git a/contracts/IRecovery.sol b/contracts/IRecovery.sol
index 16fed99c1e..a4d7f98681 100644
--- a/contracts/IRecovery.sol
+++ b/contracts/IRecovery.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 pragma experimental "ABIEncoderV2";
 
 
diff --git a/contracts/IReputationMiningCycle.sol b/contracts/IReputationMiningCycle.sol
index 0426de5a35..5ecbb7097b 100644
--- a/contracts/IReputationMiningCycle.sol
+++ b/contracts/IReputationMiningCycle.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 pragma experimental "ABIEncoderV2";
 
 import "./ReputationMiningCycleDataTypes.sol";
@@ -28,12 +27,12 @@ contract IReputationMiningCycle is ReputationMiningCycleDataTypes {
   /// @param _round The dispute round to query
   /// @param _index The index in the dispute round to query
   /// @return The elements of the Submission struct for the submission requested. See ReputationMiningCycleDataTypes for the full description
-  function getDisputeRounds(uint256 _round, uint256 _index) public view returns (Submission submission);
+  function getDisputeRounds(uint256 _round, uint256 _index) public view returns (Submission memory submission);
 
   /// @notice The getter for the hashSubmissions mapping, which keeps track of submissions by user.
   /// @param _user Address of the user
   /// @return submission the Submission struct for the submission requested. See ReputationMiningCycleDataTypes.sol for the full description
-  function getReputationHashSubmissions(address _user) public view returns (Submission submission);
+  function getReputationHashSubmissions(address _user) public view returns (Submission memory submission);
 
   /// @notice Get the hash for the corresponding entry.
   /// @param submitter The address that submitted the hash
@@ -70,8 +69,12 @@ contract IReputationMiningCycle is ReputationMiningCycleDataTypes {
   /// @param jhIntermediateValue The contents of the Justification Tree at the key given by `targetNode` (see function description). The value of `targetNode` is computed locally to establish what to submit to this function.
   /// @param branchMask The branchMask of the Merkle proof that `jhIntermediateValue` is the value at key `targetNode`
   /// @param siblings The siblings of the Merkle proof that `jhIntermediateValue` is the value at key `targetNode`
-  function respondToBinarySearchForChallenge(uint256 round, uint256 idx, bytes jhIntermediateValue, uint branchMask, bytes32[] siblings) public;
-
+  function respondToBinarySearchForChallenge(
+    uint256 round,
+    uint256 idx,
+    bytes memory jhIntermediateValue,
+    uint branchMask,
+    bytes32[] memory siblings) public;
 
   /// @notice Confirm the result of a binary search - depending on how exactly the binary search finished, the saved binary search intermediate state might be incorrect.
   /// @notice This function ensures that the intermediate hashes saved are correct.
@@ -80,7 +83,12 @@ contract IReputationMiningCycle is ReputationMiningCycleDataTypes {
   /// @param jhIntermediateValue The contents of the Justification Tree at the key given by `targetNode` (see function description). The value of `targetNode` is computed locally to establish what to submit to this function.
   /// @param branchMask The branchMask of the Merkle proof that `jhIntermediateValue` is the value at key `targetNode`
   /// @param siblings The siblings of the Merkle proof that `jhIntermediateValue` is the value at key `targetNode`
-  function confirmBinarySearchResult(uint256 round, uint256 idx, bytes jhIntermediateValue, uint256 branchMask, bytes32[] siblings) public;
+  function confirmBinarySearchResult(
+    uint256 round,
+    uint256 idx,
+    bytes memory jhIntermediateValue,
+    uint256 branchMask,
+    bytes32[] memory siblings) public;
 
   /// @notice Respond to challenge, to establish which (if either) of the two submissions facing off are correct.
   /// @param u A `uint256[10]` array. The elements of this array, in order are:
@@ -108,16 +116,16 @@ contract IReputationMiningCycle is ReputationMiningCycleDataTypes {
   /// @dev If you know that the disagreement doesn't involve a new reputation being added, the arguments corresponding to the previous new reputation can be zeroed, as they will not be used. You must be sure
   /// that this is the case, however, otherwise you risk being found incorrect. Zeroed arguments will result in a cheaper call to this function.
   function respondToChallenge(
-    uint256[11] u, //An array of 10 UINT Params, ordered as given above.
-    bytes _reputationKey,
-    bytes32[] reputationSiblings,
-    bytes agreeStateReputationValue,
-    bytes32[] agreeStateSiblings,
-    bytes disagreeStateReputationValue,
-    bytes32[] disagreeStateSiblings,
-    bytes previousNewReputationKey,
-    bytes previousNewReputationValue,
-    bytes32[] previousNewReputationSiblings) public;
+    uint256[11] memory u, //An array of 10 UINT Params, ordered as given above.
+    bytes memory _reputationKey,
+    bytes32[] memory reputationSiblings,
+    bytes memory agreeStateReputationValue,
+    bytes32[] memory agreeStateSiblings,
+    bytes memory disagreeStateReputationValue,
+    bytes32[] memory disagreeStateSiblings,
+    bytes memory previousNewReputationKey,
+    bytes memory previousNewReputationValue,
+    bytes32[] memory previousNewReputationSiblings) public;
 
   /// @notice Verify the Justification Root Hash (JRH) for a submitted reputation hash is plausible
   /// @param round The round that the hash is currently in.
@@ -134,9 +142,9 @@ contract IReputationMiningCycle is ReputationMiningCycleDataTypes {
     uint256 round,
     uint256 index,
     uint branchMask1,
-    bytes32[] siblings1,
+    bytes32[] memory siblings1,
     uint branchMask2,
-    bytes32[] siblings2) public;
+    bytes32[] memory siblings2) public;
 
   /// @notice Add a new entry to the reputation update log
   /// @param _user The address of the user having their reputation changed by this log entry
@@ -161,7 +169,7 @@ contract IReputationMiningCycle is ReputationMiningCycleDataTypes {
   /// @notice Get the `ReputationLogEntry` at index `_id`
   /// @param _id The reputation log members array index of the entry to get
   /// @return reputationUpdateLogEntry The Reputation Update Log Entry
-  function getReputationUpdateLogEntry(uint256 _id) public view returns (ReputationLogEntry reputationUpdateLogEntry);
+  function getReputationUpdateLogEntry(uint256 _id) public view returns (ReputationLogEntry memory reputationUpdateLogEntry);
 
   /// @notice Start the reputation log with the rewards for the stakers who backed the accepted new reputation root hash.
   /// @param stakers The array of stakers addresses to receive the reward.
@@ -172,8 +180,8 @@ contract IReputationMiningCycle is ReputationMiningCycleDataTypes {
   /// @dev Note that the same address might be present multiple times in `stakers` - this is acceptable, and indicates the
   /// same address backed the same hash multiple times with different entries.
   function rewardStakersWithReputation(
-    address[] stakers,
-    uint256[] weights,
+    address[] memory stakers,
+    uint256[] memory weights,
     address metaColonyAddress,
     uint256 reward,
     uint256 miningSkillId
diff --git a/contracts/ITokenLocking.sol b/contracts/ITokenLocking.sol
index c8b680404e..84e7cec7b2 100644
--- a/contracts/ITokenLocking.sol
+++ b/contracts/ITokenLocking.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 pragma experimental "ABIEncoderV2";
 
 import "./TokenLockingDataTypes.sol";
@@ -64,7 +63,7 @@ contract ITokenLocking is TokenLockingDataTypes {
   /// @param _stakers Array of the addresses of stakers to punish
   /// @param _beneficiary Address of beneficiary to receive forfeited stake
   /// @param _amount Amount of stake to slash
-  function punishStakers(address[] _stakers, address _beneficiary, uint256 _amount) public;
+  function punishStakers(address[] memory _stakers, address _beneficiary, uint256 _amount) public;
 
   /// @notice Get global lock count for a specific token
   /// @param _token Address of the token
@@ -78,5 +77,5 @@ contract ITokenLocking is TokenLockingDataTypes {
   ///   lockCount User's token lock count
   ///   amount User's deposited amount
   ///   timestamp Timestamp of deposit
-  function getUserLock(address _token, address _user) public view returns (Lock lock);
+  function getUserLock(address _token, address _user) public view returns (Lock memory lock);
 }
diff --git a/contracts/Migrations.sol b/contracts/Migrations.sol
index 574ad421a6..43961a8c90 100644
--- a/contracts/Migrations.sol
+++ b/contracts/Migrations.sol
@@ -1,5 +1,4 @@
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 
 
 contract Migrations {
diff --git a/contracts/PatriciaTree/Bits.sol b/contracts/PatriciaTree/Bits.sol
index 07fbde0185..14606e8bbd 100644
--- a/contracts/PatriciaTree/Bits.sol
+++ b/contracts/PatriciaTree/Bits.sol
@@ -1,5 +1,4 @@
-pragma solidity ^0.4.16;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 pragma experimental "ABIEncoderV2";
 
 
diff --git a/contracts/PatriciaTree/Data.sol b/contracts/PatriciaTree/Data.sol
index f2bf7f77cd..df87830763 100644
--- a/contracts/PatriciaTree/Data.sol
+++ b/contracts/PatriciaTree/Data.sol
@@ -1,5 +1,4 @@
-pragma solidity ^0.4.16;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 pragma experimental "ABIEncoderV2";
 
 import {Bits} from "./Bits.sol";
@@ -65,7 +64,7 @@ library Data {
     return keccak256(abi.encodePacked(self.node, self.label.length, self.label.data));
   }
 
-  function insert(Tree storage self, bytes32 key, bytes value) internal {
+  function insert(Tree storage self, bytes32 key, bytes memory value) internal {
     Label memory k = Label(key, 256);
     bytes32 valueHash = keccak256(value);
     Edge memory e;
@@ -81,7 +80,7 @@ library Data {
   }
 
   // Private functions
-  function insertAtEdge(Tree storage self, Edge e, Label key, bytes32 value) private returns (Edge) {
+  function insertAtEdge(Tree storage self, Edge memory e, Label memory key, bytes32 value) private returns (Edge memory) {
     assert(key.length >= e.label.length);
     Label memory prefix;
     Label memory suffix;
diff --git a/contracts/PatriciaTree/IPatriciaTree.sol b/contracts/PatriciaTree/IPatriciaTree.sol
index 0dff384e71..5a43191178 100644
--- a/contracts/PatriciaTree/IPatriciaTree.sol
+++ b/contracts/PatriciaTree/IPatriciaTree.sol
@@ -1,5 +1,4 @@
-pragma solidity ^0.4.16;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 pragma experimental "ABIEncoderV2";
 
 import {Data} from "./Data.sol";
@@ -11,15 +10,16 @@ import "./IPatriciaTreeBase.sol";
 contract IPatriciaTree is IPatriciaTreeBase {
 
   /// @notice Insert the `key`/`value`in the appropriate place in the tree
-  function insert(bytes key, bytes value) public;
+  function insert(bytes memory key, bytes memory value) public;
 
   /// @notice Returns the Merkle-proof for the given `key`
   /// @return branchMask Bitmask with high bits at the positions in the `key` where we have branch nodes (bit in key denotes direction)
   /// @return _siblings Hashes of sibling edges
-  function getProof(bytes key) public view returns (uint branchMask, bytes32[] _siblings);
+  function getProof(bytes memory key) public view returns (uint branchMask, bytes32[] memory _siblings);
 
   /// @notice Calculates and returns a root hash for the `key`, `value`, `branchMask` and `siblings`
   /// @return rootHash The calculated hash
-  function getImpliedRoot(bytes key, bytes value, uint256 branchMask, bytes32[] siblings) public pure returns (bytes32 rootHash);
+  function getImpliedRoot(bytes memory key, bytes memory value, uint256 branchMask, bytes32[] memory siblings) 
+    public pure returns (bytes32 rootHash);
 
 }
diff --git a/contracts/PatriciaTree/IPatriciaTreeBase.sol b/contracts/PatriciaTree/IPatriciaTreeBase.sol
index 460c030443..96ca30da7f 100644
--- a/contracts/PatriciaTree/IPatriciaTreeBase.sol
+++ b/contracts/PatriciaTree/IPatriciaTreeBase.sol
@@ -1,5 +1,4 @@
-pragma solidity ^0.4.16;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 pragma experimental "ABIEncoderV2";
 
 import {Data} from "./Data.sol";
@@ -16,10 +15,10 @@ contract IPatriciaTreeBase {
 
   /// @notice Get the root edge
   /// @return e The root `Data.Edge`
-  function getRootEdge() public view returns (Data.Edge e);
+  function getRootEdge() public view returns (Data.Edge memory e);
 
   /// @notice Get the node with the given key
   /// @param hash The `keccak256` hash of the actual key
   /// @return n `Data.Node` for key `hash`
-  function getNode(bytes32 hash) public view returns (Data.Node n);
+  function getNode(bytes32 hash) public view returns (Data.Node memory n);
 }
diff --git a/contracts/PatriciaTree/IPatriciaTreeNoHash.sol b/contracts/PatriciaTree/IPatriciaTreeNoHash.sol
index 1215920f93..894a7b8338 100644
--- a/contracts/PatriciaTree/IPatriciaTreeNoHash.sol
+++ b/contracts/PatriciaTree/IPatriciaTreeNoHash.sol
@@ -1,5 +1,4 @@
-pragma solidity ^0.4.16;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 pragma experimental "ABIEncoderV2";
 
 import {Data} from "./Data.sol";
@@ -11,15 +10,15 @@ import "./IPatriciaTreeBase.sol";
 contract IPatriciaTreeNoHash is IPatriciaTreeBase {
 
   /// @notice Insert the `key`/`value`in the appropriate place in the tree
-  function insert(bytes32 key, bytes value) public;
+  function insert(bytes32 key, bytes memory value) public;
 
   /// @notice Returns the Merkle-proof for the given `key`
   /// @return branchMask Bitmask with high bits at the positions in the `key` where we have branch nodes (bit in key denotes direction)
   /// @return _siblings Hashes of sibling edges
-  function getProof(bytes32 key) public view returns (uint branchMask, bytes32[] _siblings);
+  function getProof(bytes32 key) public view returns (uint branchMask, bytes32[] memory _siblings);
 
   /// @notice Calculates and returns a root hash for the `key`, `value`, `branchMask` and `siblings`
   /// @return rootHash The calculated hash
-  function getImpliedRoot(bytes32 key, bytes value, uint256 branchMask, bytes32[] siblings) public pure returns (bytes32 rootHash);
+  function getImpliedRoot(bytes32 key, bytes memory value, uint256 branchMask, bytes32[] memory siblings) public pure returns (bytes32 rootHash);
 
 }
diff --git a/contracts/PatriciaTree/PatriciaTree.sol b/contracts/PatriciaTree/PatriciaTree.sol
index 8a63a435f5..fe3a177d73 100644
--- a/contracts/PatriciaTree/PatriciaTree.sol
+++ b/contracts/PatriciaTree/PatriciaTree.sol
@@ -1,5 +1,4 @@
-pragma solidity ^0.4.16;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 pragma experimental "ABIEncoderV2";
 
 import "./PatriciaTreeBase.sol";
@@ -10,15 +9,15 @@ import "./IPatriciaTree.sol";
 /// @notice More info at: https://github.com/chriseth/patricia-trie
 contract PatriciaTree is IPatriciaTree, PatriciaTreeBase {
 
-  function insert(bytes key, bytes value) public {
+  function insert(bytes memory key, bytes memory value) public {
     tree.insert(keccak256(key), value);
   }
 
-  function getProof(bytes key) public view returns (uint branchMask, bytes32[] _siblings) {
+  function getProof(bytes memory key) public view returns (uint branchMask, bytes32[] memory _siblings) {
     return getProofFunctionality(keccak256(key));
   }
 
-  function getImpliedRoot(bytes key, bytes value, uint branchMask, bytes32[] siblings) public
+  function getImpliedRoot(bytes memory key, bytes memory value, uint branchMask, bytes32[] memory siblings) public
   pure returns (bytes32)
   {
     return getImpliedRootHashKey(key, value, branchMask, siblings);
diff --git a/contracts/PatriciaTree/PatriciaTreeBase.sol b/contracts/PatriciaTree/PatriciaTreeBase.sol
index 543048d04c..fc57e26737 100644
--- a/contracts/PatriciaTree/PatriciaTreeBase.sol
+++ b/contracts/PatriciaTree/PatriciaTreeBase.sol
@@ -1,5 +1,4 @@
-pragma solidity ^0.4.16;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 pragma experimental "ABIEncoderV2";
 
 import {Data} from "./Data.sol";
@@ -22,15 +21,15 @@ contract PatriciaTreeBase is PatriciaTreeProofs {
     return tree.root;
   }
 
-  function getRootEdge() public view returns (Data.Edge e) {
+  function getRootEdge() public view returns (Data.Edge memory e) {
     e = tree.rootEdge;
   }
 
-  function getNode(bytes32 hash) public view returns (Data.Node n) {
+  function getNode(bytes32 hash) public view returns (Data.Node memory n) {
     n = tree.nodes[hash];
   }
 
-  function getProofFunctionality(bytes32 key) internal view returns (uint branchMask, bytes32[] _siblings) {
+  function getProofFunctionality(bytes32 key) internal view returns (uint branchMask, bytes32[] memory _siblings) {
     require(tree.root != 0, "colony-patricia-tree-zero-tree-root");
     Data.Label memory k = Data.Label(key, 256);
     Data.Edge memory e = tree.rootEdge;
diff --git a/contracts/PatriciaTree/PatriciaTreeNoHash.sol b/contracts/PatriciaTree/PatriciaTreeNoHash.sol
index 0188b0ed33..efde968bfa 100644
--- a/contracts/PatriciaTree/PatriciaTreeNoHash.sol
+++ b/contracts/PatriciaTree/PatriciaTreeNoHash.sol
@@ -1,5 +1,4 @@
-pragma solidity ^0.4.16;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 pragma experimental "ABIEncoderV2";
 
 import "./PatriciaTreeBase.sol";
@@ -10,15 +9,15 @@ import "./IPatriciaTreeNoHash.sol";
 /// @notice More info at: https://github.com/chriseth/patricia-trie
 contract PatriciaTreeNoHash is IPatriciaTreeNoHash, PatriciaTreeBase {
 
-  function insert(bytes32 key, bytes value) public {
+  function insert(bytes32 key, bytes memory value) public {
     tree.insert(key, value);
   }
 
-  function getProof(bytes32 key) public view returns (uint branchMask, bytes32[] _siblings) {
+  function getProof(bytes32 key) public view returns (uint branchMask, bytes32[] memory _siblings) {
     return getProofFunctionality(key);
   }
 
-  function getImpliedRoot(bytes32 key, bytes value, uint branchMask, bytes32[] siblings) public
+  function getImpliedRoot(bytes32 key, bytes memory value, uint branchMask, bytes32[] memory siblings) public
   pure returns (bytes32)
   {
     return getImpliedRootNoHashKey(key, value, branchMask, siblings);
diff --git a/contracts/PatriciaTree/PatriciaTreeProofs.sol b/contracts/PatriciaTree/PatriciaTreeProofs.sol
index e25fea8737..41af6ad14f 100644
--- a/contracts/PatriciaTree/PatriciaTreeProofs.sol
+++ b/contracts/PatriciaTree/PatriciaTreeProofs.sol
@@ -1,5 +1,4 @@
-pragma solidity ^0.4.16;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 pragma experimental "ABIEncoderV2";
 
 import {Data} from "./Data.sol";
@@ -13,7 +12,7 @@ contract PatriciaTreeProofs {
   using Data for Data.Edge;
   using Data for Data.Label;
 
-  function getImpliedRootHashKey(bytes key, bytes value, uint256 branchMask, bytes32[] siblings) internal
+  function getImpliedRootHashKey(bytes memory key, bytes memory value, uint256 branchMask, bytes32[] memory siblings) internal
   pure returns (bytes32)
   {
     bytes32 hash;
@@ -21,7 +20,7 @@ contract PatriciaTreeProofs {
     return hash;
   }
 
-  function getImpliedRootNoHashKey(bytes32 key, bytes value, uint256 branchMask, bytes32[] siblings) internal
+  function getImpliedRootNoHashKey(bytes32 key, bytes memory value, uint256 branchMask, bytes32[] memory siblings) internal
   pure returns (bytes32)
   {
     bytes32 hash;
@@ -29,15 +28,15 @@ contract PatriciaTreeProofs {
     return hash;
   }
 
-  function getFinalPairAndImpliedRootNoHash(bytes32 key, bytes value, uint256 branchMask, bytes32[] siblings) internal
-  pure returns (bytes32, bytes32[2])
+  function getFinalPairAndImpliedRootNoHash(bytes32 key, bytes memory value, uint256 branchMask, bytes32[] memory siblings) internal
+  pure returns (bytes32, bytes32[2] memory)
   {
     return getImpliedRootFunctionality(key, keccak256(value), branchMask, siblings);
   }
 
   // solium-disable-next-line security/no-assign-params
-  function getImpliedRootFunctionality(bytes32 keyHash, bytes32 valueHash, uint256 branchMask, bytes32[] siblings) private
-  pure returns (bytes32, bytes32[2])
+  function getImpliedRootFunctionality(bytes32 keyHash, bytes32 valueHash, uint256 branchMask, bytes32[] memory siblings) private
+  pure returns (bytes32, bytes32[2] memory)
   {
     Data.Label memory k = Data.Label(keyHash, 256);
     Data.Edge memory e;
@@ -57,8 +56,8 @@ contract PatriciaTreeProofs {
     if (branchMask == 0) {
       e.label = k;
     } else {
-      uint bitSet = branchMask.lowestBitSet();
-      (k, e.label) = k.splitAt(255 - bitSet);
+      uint lowestBitSet = branchMask.lowestBitSet();
+      (k, e.label) = k.splitAt(255 - lowestBitSet);
       (, e.label) = e.label.chopFirstBit();
     }
     return (e.edgeHash(), edgeHashes);
diff --git a/contracts/ReputationMiningCycle.sol b/contracts/ReputationMiningCycle.sol
index 73c9547530..8f9f7fd8b0 100644
--- a/contracts/ReputationMiningCycle.sol
+++ b/contracts/ReputationMiningCycle.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 pragma experimental "ABIEncoderV2";
 
 import "../lib/dappsys/math.sol";
@@ -104,7 +103,7 @@ contract ReputationMiningCycle is ReputationMiningCycleStorage, PatriciaTreeProo
   /// @dev This will only be called once, by ColonyNetwork, in the same transaction that deploys this contract
   function initialise(address _tokenLockingAddress, address _clnyTokenAddress) public {
     // Prevent this being called multiple times
-    require(colonyNetworkAddress == 0, "colony-reputation-mining-cycle-already-initialised");
+    require(colonyNetworkAddress == address(0x0), "colony-reputation-mining-cycle-already-initialised");
     colonyNetworkAddress = msg.sender;
     tokenLockingAddress = _tokenLockingAddress;
     clnyTokenAddress = _clnyTokenAddress;
@@ -297,9 +296,9 @@ contract ReputationMiningCycle is ReputationMiningCycleStorage, PatriciaTreeProo
   function respondToBinarySearchForChallenge(
     uint256 round,
     uint256 idx,
-    bytes jhIntermediateValue,
+    bytes memory jhIntermediateValue,
     uint256 branchMask,
-    bytes32[] siblings
+    bytes32[] memory siblings
   ) public
   {
     require(disputeRounds[round][idx].lowerBound != disputeRounds[round][idx].upperBound, "colony-reputation-mining-challenge-not-active");
@@ -329,9 +328,9 @@ contract ReputationMiningCycle is ReputationMiningCycleStorage, PatriciaTreeProo
   function confirmBinarySearchResult(
     uint256 round,
     uint256 idx,
-    bytes jhIntermediateValue,
+    bytes memory jhIntermediateValue,
     uint256 branchMask,
-    bytes32[] siblings
+    bytes32[] memory siblings
   ) public
   {
     require(disputeRounds[round][idx].jrhNNodes != 0, "colony-reputation-jrh-hash-not-verified");
@@ -364,9 +363,9 @@ contract ReputationMiningCycle is ReputationMiningCycleStorage, PatriciaTreeProo
     uint256 round,
     uint256 index,
     uint256 branchMask1,
-    bytes32[] siblings1,
+    bytes32[] memory siblings1,
     uint256 branchMask2,
-    bytes32[] siblings2
+    bytes32[] memory siblings2
   ) public
   {
     // Require we've not submitted already.
@@ -434,21 +433,21 @@ contract ReputationMiningCycle is ReputationMiningCycleStorage, PatriciaTreeProo
     return reputationUpdateLog.length;
   }
 
-  function getReputationUpdateLogEntry(uint256 _id) public view returns (ReputationLogEntry) {
+  function getReputationUpdateLogEntry(uint256 _id) public view returns (ReputationLogEntry memory) {
     return reputationUpdateLog[_id];
   }
 
-  function getReputationHashSubmissions(address _user) public view returns (Submission) {
+  function getReputationHashSubmissions(address _user) public view returns (Submission memory) {
     return reputationHashSubmissions[_user];
   }
 
-  function getDisputeRounds(uint256 _round, uint256 _index) public view returns (Submission) {
+  function getDisputeRounds(uint256 _round, uint256 _index) public view returns (Submission memory) {
     return disputeRounds[_round][_index];
   }
 
   function rewardStakersWithReputation(
-    address[] stakers,
-    uint256[] weights,
+    address[] memory stakers,
+    uint256[] memory weights,
     address metaColonyAddress,
     uint256 reward,
     uint256 miningSkillId
@@ -480,16 +479,16 @@ contract ReputationMiningCycle is ReputationMiningCycleStorage, PatriciaTreeProo
   // Internal functions
   /////////////////////////
 
-  function submissionWindowClosed() internal view returns(bool) {
+  function submissionWindowClosed() internal view returns (bool) {
     return now - reputationMiningWindowOpenTimestamp >= MINING_WINDOW_SIZE;
   }
 
   function processBinaryChallengeSearchResponse(
     uint256 round,
     uint256 idx,
-    bytes jhIntermediateValue,
+    bytes memory jhIntermediateValue,
     uint256 targetNode,
-    bytes32[2] lastSiblings
+    bytes32[2] memory lastSiblings
   ) internal
   {
     disputeRounds[round][idx].lastResponseTimestamp = now;
@@ -515,39 +514,6 @@ contract ReputationMiningCycle is ReputationMiningCycleStorage, PatriciaTreeProo
     }
   }
 
-  function nextPowerOfTwoInclusive(uint256 v) pure private returns (uint) { // solium-disable-line security/no-assign-params
-    // Returns the next power of two, or v if v is already a power of two.
-    // Doesn't work for zero.
-    v--;
-    v |= v >> 1;
-    v |= v >> 2;
-    v |= v >> 4;
-    v |= v >> 8;
-    v |= v >> 16;
-    v |= v >> 32;
-    v |= v >> 64;
-    v |= v >> 128;
-    v++;
-    return v;
-  }
-
-  function expectedProofLength(uint256 nNodes, uint256 node) pure private returns (uint256) { // solium-disable-line security/no-assign-params
-    nNodes -= 1;
-    uint256 nextPowerOfTwo = nextPowerOfTwoInclusive(nNodes + 1);
-    uint256 layers = 0;
-    while (nNodes != 0 && (node+1 > nextPowerOfTwo / 2)) {
-      nNodes -= nextPowerOfTwo/2;
-      node -= nextPowerOfTwo/2;
-      layers += 1;
-      nextPowerOfTwo = nextPowerOfTwoInclusive(nNodes + 1);
-    }
-    while (nextPowerOfTwo > 1) {
-      layers += 1;
-      nextPowerOfTwo >>= 1;
-    }
-    return layers;
-  }
-
   function processBinaryChallengeSearchStep(uint256 round, uint256 idx, uint256 targetNode) internal {
     uint256 opponentIdx = (idx % 2 == 1 ? idx-1 : idx + 1);
     uint256 searchWidth = (disputeRounds[round][idx].upperBound - disputeRounds[round][idx].lowerBound) + 1;
@@ -589,7 +555,7 @@ contract ReputationMiningCycle is ReputationMiningCycleStorage, PatriciaTreeProo
     disputeRounds[round][opponentIdx].lastResponseTimestamp = now;
   }
 
-  function checkJRHProof1(bytes32 jrh, uint256 branchMask1, bytes32[] siblings1, uint256 reputationRootHashNNodes) internal view {
+  function checkJRHProof1(bytes32 jrh, uint256 branchMask1, bytes32[] memory siblings1, uint256 reputationRootHashNNodes) internal view {
     // Proof 1 needs to prove that they started with the current reputation root hash
     bytes32 reputationRootHash = IColonyNetwork(colonyNetworkAddress).getReputationRootHash();
     bytes memory jhLeafValue = new bytes(64);
@@ -605,7 +571,7 @@ contract ReputationMiningCycle is ReputationMiningCycleStorage, PatriciaTreeProo
     uint256 round,
     uint256 index,
     uint256 branchMask2,
-    bytes32[] siblings2,
+    bytes32[] memory siblings2,
     uint256 reputationRootHashNNodes
   ) internal
   {
@@ -652,4 +618,36 @@ contract ReputationMiningCycle is ReputationMiningCycleStorage, PatriciaTreeProo
     startMemberOfPair(roundNumber, nInRound-2);
   }
 
+  function nextPowerOfTwoInclusive(uint256 v) private pure returns (uint) { // solium-disable-line security/no-assign-params
+    // Returns the next power of two, or v if v is already a power of two.
+    // Doesn't work for zero.
+    v--;
+    v |= v >> 1;
+    v |= v >> 2;
+    v |= v >> 4;
+    v |= v >> 8;
+    v |= v >> 16;
+    v |= v >> 32;
+    v |= v >> 64;
+    v |= v >> 128;
+    v++;
+    return v;
+  }
+
+  function expectedProofLength(uint256 nNodes, uint256 node) private pure returns (uint256) { // solium-disable-line security/no-assign-params
+    nNodes -= 1;
+    uint256 nextPowerOfTwo = nextPowerOfTwoInclusive(nNodes + 1);
+    uint256 layers = 0;
+    while (nNodes != 0 && (node+1 > nextPowerOfTwo / 2)) {
+      nNodes -= nextPowerOfTwo/2;
+      node -= nextPowerOfTwo/2;
+      layers += 1;
+      nextPowerOfTwo = nextPowerOfTwoInclusive(nNodes + 1);
+    }
+    while (nextPowerOfTwo > 1) {
+      layers += 1;
+      nextPowerOfTwo >>= 1;
+    }
+    return layers;
+  }
 }
diff --git a/contracts/ReputationMiningCycleDataTypes.sol b/contracts/ReputationMiningCycleDataTypes.sol
index b192f8c228..d6fa01690e 100644
--- a/contracts/ReputationMiningCycleDataTypes.sol
+++ b/contracts/ReputationMiningCycleDataTypes.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 
 
 contract ReputationMiningCycleDataTypes {
diff --git a/contracts/ReputationMiningCycleRespond.sol b/contracts/ReputationMiningCycleRespond.sol
index af6d5bdfdd..5f314d2cd0 100644
--- a/contracts/ReputationMiningCycleRespond.sol
+++ b/contracts/ReputationMiningCycleRespond.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 pragma experimental "ABIEncoderV2";
 
 import "../lib/dappsys/math.sol";
@@ -67,16 +66,16 @@ contract ReputationMiningCycleRespond is ReputationMiningCycleStorage, PatriciaT
   uint constant DECAY_DENOMINATOR = 1000000000000000;
 
   function respondToChallenge(
-    uint256[11] u, //An array of 11 UINT Params, ordered as given above.
-    bytes _reputationKey,
-    bytes32[] reputationSiblings,
-    bytes agreeStateReputationValue,
-    bytes32[] agreeStateSiblings,
-    bytes disagreeStateReputationValue,
-    bytes32[] disagreeStateSiblings,
-    bytes previousNewReputationKey,
-    bytes previousNewReputationValue,
-    bytes32[] previousNewReputationSiblings
+    uint256[11] memory u, //An array of 11 UINT Params, ordered as given above.
+    bytes memory _reputationKey,
+    bytes32[] memory reputationSiblings,
+    bytes memory agreeStateReputationValue,
+    bytes32[] memory agreeStateSiblings,
+    bytes memory disagreeStateReputationValue,
+    bytes32[] memory disagreeStateSiblings,
+    bytes memory previousNewReputationKey,
+    bytes memory previousNewReputationValue,
+    bytes32[] memory previousNewReputationSiblings
   ) public
     challengeOpen(u[U_ROUND], u[U_IDX])
   {
@@ -132,7 +131,7 @@ contract ReputationMiningCycleRespond is ReputationMiningCycleStorage, PatriciaT
   // Internal functions
   /////////////////////////
 
-  function checkKey(uint256[11] u, bytes memory _reputationKey, bytes memory _reputationValue) internal {
+  function checkKey(uint256[11] memory u, bytes memory _reputationKey, bytes memory _reputationValue) internal {
     // If the state transition we're checking is less than the number of nodes in the currently accepted state, it's a decay transition
     // Otherwise, look up the corresponding entry in the reputation log.
     uint256 updateNumber = disputeRounds[u[U_ROUND]][u[U_IDX]].lowerBound - 1;
@@ -196,8 +195,8 @@ contract ReputationMiningCycleRespond is ReputationMiningCycleStorage, PatriciaT
   {
     // Work out the expected userAddress and skillId for this updateNumber in this logEntry.
     if ((updateNumber - logEntry.nPreviousUpdates + 1) <= logEntry.nUpdates / 2 ) {
-      // Then we're updating a colony-wide total, so we expect an address of 0x0
-      expectedAddress = 0x0;
+      // Then we're updating a colony-wide total, so we expect an address of address(0x0)
+      expectedAddress = address(0x0);
     } else {
       // We're updating a user-specific total
       expectedAddress = logEntry.user;
@@ -226,11 +225,11 @@ contract ReputationMiningCycleRespond is ReputationMiningCycleStorage, PatriciaT
   }
 
   function proveBeforeReputationValue(
-    uint256[11] u,
-    bytes _reputationKey,
-    bytes32[] reputationSiblings,
-    bytes agreeStateReputationValue,
-    bytes32[] agreeStateSiblings
+    uint256[11] memory u,
+    bytes memory _reputationKey,
+    bytes32[] memory reputationSiblings,
+    bytes memory agreeStateReputationValue,
+    bytes32[] memory agreeStateSiblings
   ) internal
   {
     bytes32 jrh = disputeRounds[u[U_ROUND]][u[U_IDX]].jrh;
@@ -278,11 +277,11 @@ contract ReputationMiningCycleRespond is ReputationMiningCycleStorage, PatriciaT
   }
 
   function proveAfterReputationValue(
-    uint256[11] u,
-    bytes _reputationKey,
-    bytes32[] reputationSiblings,
-    bytes disagreeStateReputationValue,
-    bytes32[] disagreeStateSiblings
+    uint256[11] memory u,
+    bytes memory _reputationKey,
+    bytes32[] memory reputationSiblings,
+    bytes memory disagreeStateReputationValue,
+    bytes32[] memory disagreeStateSiblings
   ) internal view
   {
     bytes32 jrh = disputeRounds[u[U_ROUND]][u[U_IDX]].jrh;
@@ -313,10 +312,10 @@ contract ReputationMiningCycleRespond is ReputationMiningCycleStorage, PatriciaT
   }
 
   function performReputationCalculation(
-    uint256[11] u,
-    bytes agreeStateReputationValueBytes,
-    bytes disagreeStateReputationValueBytes,
-    bytes previousNewReputationValueBytes
+    uint256[11] memory u,
+    bytes memory agreeStateReputationValueBytes,
+    bytes memory disagreeStateReputationValueBytes,
+    bytes memory previousNewReputationValueBytes
   ) internal view
   {
     // TODO: Possibility of reputation loss - child reputations do not lose the whole of logEntry.amount, but the same fraction logEntry amount is of the user's reputation in skill given by logEntry.skillId
@@ -368,11 +367,11 @@ contract ReputationMiningCycleRespond is ReputationMiningCycleStorage, PatriciaT
   }
 
   function checkPreviousReputationInState(
-    uint256[11] u,
-    bytes32[] agreeStateSiblings,
-    bytes previousNewReputationKey,
-    bytes previousNewReputationValue,
-    bytes32[] previousNewReputationSiblings
+    uint256[11] memory u,
+    bytes32[] memory agreeStateSiblings,
+    bytes memory previousNewReputationKey,
+    bytes memory previousNewReputationValue,
+    bytes32[] memory previousNewReputationSiblings
     ) internal view
   {
     // We binary searched to the first disagreement, so the last agreement is the one before
@@ -395,7 +394,7 @@ contract ReputationMiningCycleRespond is ReputationMiningCycleStorage, PatriciaT
     require(impliedRoot == disputeRounds[u[U_ROUND]][u[U_IDX]].jrh, "colony-reputation-mining-last-state-disagreement");
   }
 
-  function saveProvedReputation(uint256[11] u, bytes previousNewReputationValue) internal {
+  function saveProvedReputation(uint256[11] memory u, bytes memory previousNewReputationValue) internal {
     uint256 previousReputationUID;
     assembly {
       previousReputationUID := mload(add(previousNewReputationValue,0x40))
@@ -409,6 +408,4 @@ contract ReputationMiningCycleRespond is ReputationMiningCycleStorage, PatriciaT
     // Save the index for tiebreak scenarios later.
     disputeRounds[u[U_ROUND]][u[U_IDX]].provedPreviousReputationUID = previousReputationUID;
   }
-
-
 }
diff --git a/contracts/ReputationMiningCycleStorage.sol b/contracts/ReputationMiningCycleStorage.sol
index a692ce10de..0a75d21b1a 100644
--- a/contracts/ReputationMiningCycleStorage.sol
+++ b/contracts/ReputationMiningCycleStorage.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23 <0.5.0;
 
 import "../lib/dappsys/auth.sol";
 import "./ReputationMiningCycleDataTypes.sol";
diff --git a/contracts/Resolver.sol b/contracts/Resolver.sol
index 3d40268f32..efab9c5a4a 100644
--- a/contracts/Resolver.sol
+++ b/contracts/Resolver.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 
 import "../lib/dappsys/auth.sol";
 
@@ -24,7 +23,7 @@ import "../lib/dappsys/auth.sol";
 contract Resolver is DSAuth {
   mapping (bytes4 => address) public pointers;
 
-  function register(string signature, address destination) public
+  function register(string memory signature, address destination) public
   auth
   {
     pointers[stringToSig(signature)] = destination;
@@ -34,7 +33,7 @@ contract Resolver is DSAuth {
     return pointers[sig];
   }
 
-  function stringToSig(string signature) public pure returns(bytes4) {
+  function stringToSig(string memory signature) public pure returns(bytes4) {
     return bytes4(keccak256(abi.encodePacked(signature)));
   }
 }
diff --git a/contracts/SafeMath.sol b/contracts/SafeMath.sol
index b565af526d..6fc6163131 100644
--- a/contracts/SafeMath.sol
+++ b/contracts/SafeMath.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 
 
 library SafeMath {
diff --git a/contracts/TokenLocking.sol b/contracts/TokenLocking.sol
index 7629a28d95..bca5664577 100644
--- a/contracts/TokenLocking.sol
+++ b/contracts/TokenLocking.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 pragma experimental "ABIEncoderV2";
 
 import "./ERC20Extended.sol";
@@ -131,7 +130,7 @@ contract TokenLocking is TokenLockingStorage, DSMath {
     emit UserTokenWithdrawn(_token, msg.sender, _amount);
   }
 
-  function punishStakers(address[] _stakers, address _beneficiary, uint256 _amount) public onlyReputationMiningCycle {
+  function punishStakers(address[] memory _stakers, address _beneficiary, uint256 _amount) public onlyReputationMiningCycle {
     address clnyToken = IMetaColony(IColonyNetwork(colonyNetwork).getMetaColony()).getToken();
     uint256 lostStake;
     // Passing an array so that we don't incur the EtherRouter overhead for each staker if we looped over
@@ -150,7 +149,7 @@ contract TokenLocking is TokenLockingStorage, DSMath {
     return totalLockCount[_token];
   }
 
-  function getUserLock(address _token, address _user) public view returns (Lock lock) {
+  function getUserLock(address _token, address _user) public view returns (Lock memory lock) {
     lock = userLocks[_token][_user];
   }
 }
diff --git a/contracts/TokenLockingDataTypes.sol b/contracts/TokenLockingDataTypes.sol
index e253943077..e978d06d1b 100644
--- a/contracts/TokenLockingDataTypes.sol
+++ b/contracts/TokenLockingDataTypes.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 
 
 contract TokenLockingDataTypes {
diff --git a/contracts/TokenLockingStorage.sol b/contracts/TokenLockingStorage.sol
index 4f98e7d372..1667976a8f 100644
--- a/contracts/TokenLockingStorage.sol
+++ b/contracts/TokenLockingStorage.sol
@@ -15,8 +15,7 @@
   along with The Colony Network. If not, see <http://www.gnu.org/licenses/>.
 */
 
-pragma solidity ^0.4.23;
-pragma experimental "v0.5.0";
+pragma solidity >=0.4.23;
 pragma experimental "ABIEncoderV2";
 
 import "../lib/dappsys/auth.sol";
diff --git a/contracts/ens/ENS.sol b/contracts/ens/ENS.sol
index 83da0b3b12..aeca9b3665 100644
--- a/contracts/ens/ENS.sol
+++ b/contracts/ens/ENS.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity >=0.4.23;
 
 
 /// @title The ENS interface.
diff --git a/contracts/ens/ENSRegistry.sol b/contracts/ens/ENSRegistry.sol
index f8f6e11a50..d8ce408b34 100644
--- a/contracts/ens/ENSRegistry.sol
+++ b/contracts/ens/ENSRegistry.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity >=0.4.23;
 
 import "./ENS.sol";
 
@@ -17,7 +17,7 @@ contract ENSRegistry is ENS {
   // Permits modifications only by the owner of the specified node, or if unowned.
   modifier onlyOwner(bytes32 node) {
     address currentOwner = records[node].owner;
-    require(currentOwner == 0 || currentOwner == msg.sender, "colony-ens-non-owner-access");
+    require(currentOwner == address(0x0) || currentOwner == msg.sender, "colony-ens-non-owner-access");
     _;
   }
 
@@ -39,7 +39,7 @@ contract ENSRegistry is ENS {
   /// @param label The hash of the label specifying the subnode.
   /// @param owner The address of the new owner.
   function setSubnodeOwner(bytes32 node, bytes32 label, address owner) public onlyOwner(node) {
-    require(records[node].owner != 0, "unowned-node");
+    require(records[node].owner != address(0x0), "unowned-node");
     bytes32 subnode = keccak256(abi.encodePacked(node, label));
     emit NewOwner(node, label, owner);
     records[subnode].owner = owner;
diff --git a/contracts/gnosis/MultiSigWallet.sol b/contracts/gnosis/MultiSigWallet.sol
deleted file mode 100644
index 96fc10f5e3..0000000000
--- a/contracts/gnosis/MultiSigWallet.sol
+++ /dev/null
@@ -1,370 +0,0 @@
-pragma solidity ^0.4.15;
-
-
-/// @title Multisignature wallet - Allows multiple parties to agree on transactions before execution.
-/// @author Stefan George - <stefan.george@consensys.net>
-contract MultiSigWallet {
-
-    /*
-     *  Events
-     */
-    event Confirmation(address indexed sender, uint indexed transactionId);
-    event Revocation(address indexed sender, uint indexed transactionId);
-    event Submission(uint indexed transactionId);
-    event Execution(uint indexed transactionId);
-    event ExecutionFailure(uint indexed transactionId);
-    event Deposit(address indexed sender, uint value);
-    event OwnerAddition(address indexed owner);
-    event OwnerRemoval(address indexed owner);
-    event RequirementChange(uint required);
-
-    /*
-     *  Constants
-     */
-    uint constant public MAX_OWNER_COUNT = 50;
-
-    /*
-     *  Storage
-     */
-    mapping (uint => Transaction) public transactions;
-    mapping (uint => mapping (address => bool)) public confirmations;
-    mapping (address => bool) public isOwner;
-    address[] public owners;
-    uint public required;
-    uint public transactionCount;
-
-    struct Transaction {
-        address destination;
-        uint value;
-        bytes data;
-        bool executed;
-    }
-
-    /*
-     *  Modifiers
-     */
-    modifier onlyWallet() {
-        require(msg.sender == address(this));
-        _;
-    }
-
-    modifier ownerDoesNotExist(address owner) {
-        require(!isOwner[owner]);
-        _;
-    }
-
-    modifier ownerExists(address owner) {
-        require(isOwner[owner]);
-        _;
-    }
-
-    modifier transactionExists(uint transactionId) {
-        require(transactions[transactionId].destination != 0);
-        _;
-    }
-
-    modifier confirmed(uint transactionId, address owner) {
-        require(confirmations[transactionId][owner]);
-        _;
-    }
-
-    modifier notConfirmed(uint transactionId, address owner) {
-        require(!confirmations[transactionId][owner]);
-        _;
-    }
-
-    modifier notExecuted(uint transactionId) {
-        require(!transactions[transactionId].executed);
-        _;
-    }
-
-    modifier notNull(address _address) {
-        require(_address != 0);
-        _;
-    }
-
-    modifier validRequirement(uint ownerCount, uint _required) {
-        require(ownerCount <= MAX_OWNER_COUNT
-            && _required <= ownerCount
-            && _required != 0
-            && ownerCount != 0);
-        _;
-    }
-
-    /// @dev Fallback function allows to deposit ether.
-    function()
-        payable
-    {
-        if (msg.value > 0)
-            Deposit(msg.sender, msg.value);
-    }
-
-    /*
-     * Public functions
-     */
-    /// @dev Contract constructor sets initial owners and required number of confirmations.
-    /// @param _owners List of initial owners.
-    /// @param _required Number of required confirmations.
-    function MultiSigWallet(address[] _owners, uint _required)
-        public
-        validRequirement(_owners.length, _required)
-    {
-        for (uint i=0; i<_owners.length; i++) {
-            require(!isOwner[_owners[i]] && _owners[i] != 0);
-            isOwner[_owners[i]] = true;
-        }
-        owners = _owners;
-        required = _required;
-    }
-
-    /// @dev Allows to add a new owner. Transaction has to be sent by wallet.
-    /// @param owner Address of new owner.
-    function addOwner(address owner)
-        public
-        onlyWallet
-        ownerDoesNotExist(owner)
-        notNull(owner)
-        validRequirement(owners.length + 1, required)
-    {
-        isOwner[owner] = true;
-        owners.push(owner);
-        OwnerAddition(owner);
-    }
-
-    /// @dev Allows to remove an owner. Transaction has to be sent by wallet.
-    /// @param owner Address of owner.
-    function removeOwner(address owner)
-        public
-        onlyWallet
-        ownerExists(owner)
-    {
-        isOwner[owner] = false;
-        for (uint i=0; i<owners.length - 1; i++)
-            if (owners[i] == owner) {
-                owners[i] = owners[owners.length - 1];
-                break;
-            }
-        owners.length -= 1;
-        if (required > owners.length)
-            changeRequirement(owners.length);
-        OwnerRemoval(owner);
-    }
-
-    /// @dev Allows to replace an owner with a new owner. Transaction has to be sent by wallet.
-    /// @param owner Address of owner to be replaced.
-    /// @param newOwner Address of new owner.
-    function replaceOwner(address owner, address newOwner)
-        public
-        onlyWallet
-        ownerExists(owner)
-        ownerDoesNotExist(newOwner)
-    {
-        for (uint i=0; i<owners.length; i++)
-            if (owners[i] == owner) {
-                owners[i] = newOwner;
-                break;
-            }
-        isOwner[owner] = false;
-        isOwner[newOwner] = true;
-        OwnerRemoval(owner);
-        OwnerAddition(newOwner);
-    }
-
-    /// @dev Allows to change the number of required confirmations. Transaction has to be sent by wallet.
-    /// @param _required Number of required confirmations.
-    function changeRequirement(uint _required)
-        public
-        onlyWallet
-        validRequirement(owners.length, _required)
-    {
-        required = _required;
-        RequirementChange(_required);
-    }
-
-    /// @dev Allows an owner to submit and confirm a transaction.
-    /// @param destination Transaction target address.
-    /// @param value Transaction ether value.
-    /// @param data Transaction data payload.
-    /// @return Returns transaction ID.
-    function submitTransaction(address destination, uint value, bytes data)
-        public
-        returns (uint transactionId)
-    {
-        transactionId = addTransaction(destination, value, data);
-        confirmTransaction(transactionId);
-    }
-
-    /// @dev Allows an owner to confirm a transaction.
-    /// @param transactionId Transaction ID.
-    function confirmTransaction(uint transactionId)
-        public
-        ownerExists(msg.sender)
-        transactionExists(transactionId)
-        notConfirmed(transactionId, msg.sender)
-    {
-        confirmations[transactionId][msg.sender] = true;
-        Confirmation(msg.sender, transactionId);
-        executeTransaction(transactionId);
-    }
-
-    /// @dev Allows an owner to revoke a confirmation for a transaction.
-    /// @param transactionId Transaction ID.
-    function revokeConfirmation(uint transactionId)
-        public
-        ownerExists(msg.sender)
-        confirmed(transactionId, msg.sender)
-        notExecuted(transactionId)
-    {
-        confirmations[transactionId][msg.sender] = false;
-        Revocation(msg.sender, transactionId);
-    }
-
-    /// @dev Allows anyone to execute a confirmed transaction.
-    /// @param transactionId Transaction ID.
-    function executeTransaction(uint transactionId)
-        public
-        ownerExists(msg.sender)
-        confirmed(transactionId, msg.sender)
-        notExecuted(transactionId)
-    {
-        if (isConfirmed(transactionId)) {
-            Transaction storage txn = transactions[transactionId];
-            txn.executed = true;
-            if (txn.destination.call.value(txn.value)(txn.data))
-                Execution(transactionId);
-            else {
-                ExecutionFailure(transactionId);
-                txn.executed = false;
-            }
-        }
-    }
-
-    /// @dev Returns the confirmation status of a transaction.
-    /// @param transactionId Transaction ID.
-    /// @return Confirmation status.
-    function isConfirmed(uint transactionId)
-        public
-        constant
-        returns (bool)
-    {
-        uint count = 0;
-        for (uint i=0; i<owners.length; i++) {
-            if (confirmations[transactionId][owners[i]])
-                count += 1;
-            if (count == required)
-                return true;
-        }
-    }
-
-    /*
-     * Internal functions
-     */
-    /// @dev Adds a new transaction to the transaction mapping, if transaction does not exist yet.
-    /// @param destination Transaction target address.
-    /// @param value Transaction ether value.
-    /// @param data Transaction data payload.
-    /// @return Returns transaction ID.
-    function addTransaction(address destination, uint value, bytes data)
-        internal
-        notNull(destination)
-        returns (uint transactionId)
-    {
-        transactionId = transactionCount;
-        transactions[transactionId] = Transaction({
-            destination: destination,
-            value: value,
-            data: data,
-            executed: false
-        });
-        transactionCount += 1;
-        Submission(transactionId);
-    }
-
-    /*
-     * Web3 call functions
-     */
-    /// @dev Returns number of confirmations of a transaction.
-    /// @param transactionId Transaction ID.
-    /// @return Number of confirmations.
-    function getConfirmationCount(uint transactionId)
-        public
-        constant
-        returns (uint count)
-    {
-        for (uint i=0; i<owners.length; i++)
-            if (confirmations[transactionId][owners[i]])
-                count += 1;
-    }
-
-    /// @dev Returns total number of transactions after filers are applied.
-    /// @param pending Include pending transactions.
-    /// @param executed Include executed transactions.
-    /// @return Total number of transactions after filters are applied.
-    function getTransactionCount(bool pending, bool executed)
-        public
-        constant
-        returns (uint count)
-    {
-        for (uint i=0; i<transactionCount; i++)
-            if (   pending && !transactions[i].executed
-                || executed && transactions[i].executed)
-                count += 1;
-    }
-
-    /// @dev Returns list of owners.
-    /// @return List of owner addresses.
-    function getOwners()
-        public
-        constant
-        returns (address[])
-    {
-        return owners;
-    }
-
-    /// @dev Returns array with owner addresses, which confirmed transaction.
-    /// @param transactionId Transaction ID.
-    /// @return Returns array of owner addresses.
-    function getConfirmations(uint transactionId)
-        public
-        constant
-        returns (address[] _confirmations)
-    {
-        address[] memory confirmationsTemp = new address[](owners.length);
-        uint count = 0;
-        uint i;
-        for (i=0; i<owners.length; i++)
-            if (confirmations[transactionId][owners[i]]) {
-                confirmationsTemp[count] = owners[i];
-                count += 1;
-            }
-        _confirmations = new address[](count);
-        for (i=0; i<count; i++)
-            _confirmations[i] = confirmationsTemp[i];
-    }
-
-    /// @dev Returns list of transaction IDs in defined range.
-    /// @param from Index start position of transaction array.
-    /// @param to Index end position of transaction array.
-    /// @param pending Include pending transactions.
-    /// @param executed Include executed transactions.
-    /// @return Returns array of transaction IDs.
-    function getTransactionIds(uint from, uint to, bool pending, bool executed)
-        public
-        constant
-        returns (uint[] _transactionIds)
-    {
-        uint[] memory transactionIdsTemp = new uint[](transactionCount);
-        uint count = 0;
-        uint i;
-        for (i=0; i<transactionCount; i++)
-            if (   pending && !transactions[i].executed
-                || executed && transactions[i].executed)
-            {
-                transactionIdsTemp[count] = i;
-                count += 1;
-            }
-        _transactionIds = new uint[](to - from);
-        for (i=from; i<to; i++)
-            _transactionIds[i - from] = transactionIdsTemp[i];
-    }
-}
\ No newline at end of file
diff --git a/helpers/upgradable-contracts.js b/helpers/upgradable-contracts.js
index 8e1d2028d5..f011d25cb4 100644
--- a/helpers/upgradable-contracts.js
+++ b/helpers/upgradable-contracts.js
@@ -63,16 +63,6 @@ export async function setupEtherRouter(interfaceContract, deployedImplementation
   }
 }
 
-export async function setupUpgradableToken(token, resolver, etherRouter) {
-  const deployedImplementations = {};
-  deployedImplementations.Token = token.address;
-  await setupEtherRouter("ERC20Extended", deployedImplementations, resolver);
-
-  await etherRouter.setResolver(resolver.address);
-  const registeredResolver = await etherRouter.resolver();
-  assert.equal(registeredResolver, resolver.address);
-}
-
 export async function setupColonyVersionResolver(colony, colonyTask, colonyFunding, contractRecovery, resolver) {
   const deployedImplementations = {};
   deployedImplementations.Colony = colony.address;
diff --git a/lib/colonyToken b/lib/colonyToken
index 7359eedaad..b9eef2fcbd 160000
--- a/lib/colonyToken
+++ b/lib/colonyToken
@@ -1 +1 @@
-Subproject commit 7359eedaadacd55a1393c795964bd61513b2af33
+Subproject commit b9eef2fcbd1c9d4363be850dd10f8fbfe099f9a0
diff --git a/lib/dappsys b/lib/dappsys
index 5f9f179380..de9114c5fa 160000
--- a/lib/dappsys
+++ b/lib/dappsys
@@ -1 +1 @@
-Subproject commit 5f9f17938048b147b43ab51f9dbcf66d4a29264b
+Subproject commit de9114c5fa1b881bf16b1414e7ed90cd3cb2e361
diff --git a/package.json b/package.json
index 582cd06442..aa3272156e 100644
--- a/package.json
+++ b/package.json
@@ -14,6 +14,7 @@
     "clean:test:contracts": "rimraf ./contracts/*Updated*.*",
     "clean:contracts": "rimraf ./build/contracts/*",
     "provision:token:contracts": "bash ./scripts/provision-token-contracts.sh",
+    "provision:token:contracts:compile": "truffle compile && bash ./scripts/provision-token-contracts.sh",
     "start:blockchain:client": "bash ./scripts/start-blockchain-client.sh",
     "stop:blockchain:client": "bash ./scripts/stop-blockchain-client.sh",
     "test:contracts": "npm run start:blockchain:client & truffle migrate --reset --compile-all && truffle test --network development",
diff --git a/scripts/check-recovery.js b/scripts/check-recovery.js
index 601e00da4a..65e0f59cc0 100644
--- a/scripts/check-recovery.js
+++ b/scripts/check-recovery.js
@@ -77,7 +77,7 @@ walkSync("./contracts/").forEach(contractName => {
 
   // Check for that all public, non-{view,pure} functions have either stoppable or recovery modifiers.
   contract.subNodes
-    .filter(child => child.type === "FunctionDefinition")
+    .filter(child => child.type === "FunctionDefinition" && child.name !== "")
     .forEach(functionDef => {
       if (!correctRecoveryModifier(functionDef)) {
         console.log("The contract", contractName, "contains a missing stoppable/recovery modifier in function", functionDef.name, ".");
diff --git a/scripts/provision-token-contracts.sh b/scripts/provision-token-contracts.sh
index e1cc12d4f7..6f18aeaa73 100644
--- a/scripts/provision-token-contracts.sh
+++ b/scripts/provision-token-contracts.sh
@@ -3,5 +3,8 @@ DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 cd $DIR
 cd ..
 
-cp lib/colonyToken/contracts/Token.sol ./contracts/Token.sol
-cp lib/colonyToken/contracts/TokenAuthority.sol ./contracts/TokenAuthority.sol
\ No newline at end of file
+test ! -d ./build/contracts/ && mkdir -p ./build/contracts/
+
+cp lib/colonyToken/build/contracts/Token.json ./build/contracts/Token.json
+cp lib/colonyToken/build/contracts/TokenAuthority.json ./build/contracts/TokenAuthority.json
+cp lib/colonyToken/build/contracts/MultiSigWallet.json ./build/contracts/MultiSigWallet.json
\ No newline at end of file
diff --git a/test/colony-network-mining.js b/test/colony-network-mining.js
index 870c97ee45..a590803ad1 100755
--- a/test/colony-network-mining.js
+++ b/test/colony-network-mining.js
@@ -204,7 +204,7 @@ contract("ColonyNetworkMining", accounts => {
       await giveUserCLNYTokens(colonyNetwork, OTHER_ACCOUNT, 9000);
       await clny.approve(tokenLocking.address, 10000, { from: OTHER_ACCOUNT });
 
-      await checkErrorRevert(tokenLocking.deposit(clny.address, 10000, { from: OTHER_ACCOUNT }), "ds-token-insufficient-balance");
+      await checkErrorRevert(tokenLocking.deposit(clny.address, 10000, { from: OTHER_ACCOUNT }));
 
       const userBalance = await clny.balanceOf(OTHER_ACCOUNT);
       assert.equal(userBalance.toNumber(), 9000);