diff --git a/packages/vvisp-contracts/libs/BytesLib.sol b/packages/vvisp-contracts/libs/BytesLib.sol
index 9d268b7..fe36f67 100644
--- a/packages/vvisp-contracts/libs/BytesLib.sol
+++ b/packages/vvisp-contracts/libs/BytesLib.sol
@@ -1,11 +1,19 @@
-pragma solidity ^0.4.24;
+pragma solidity >=0.5.0 <0.6.0;
 
 
 /**
 * @dev https://github.com/GNSPS/solidity-bytes-utils/blob/master/contracts/BytesLib.sol
 */
 library BytesLib {
-    function slice(bytes _bytes, uint _start, uint _length) internal  pure returns (bytes) {
+    function slice(
+        bytes memory _bytes,
+        uint _start,
+        uint _length
+    )
+        internal
+        pure
+        returns (bytes memory)
+    {
         require(_bytes.length >= (_start + _length));
 
         bytes memory tempBytes;
@@ -13,30 +21,30 @@ library BytesLib {
         assembly {
             switch iszero(_length)
             case 0 {
-            // Get a location of some free memory and store it in tempBytes as
-            // Solidity does for memory variables.
+                // Get a location of some free memory and store it in tempBytes as
+                // Solidity does for memory variables.
                 tempBytes := mload(0x40)
 
-            // The first word of the slice result is potentially a partial
-            // word read from the original array. To read it, we calculate
-            // the length of that partial word and start copying that many
-            // bytes into the array. The first word we copy will start with
-            // data we don't care about, but the last `lengthmod` bytes will
-            // land at the beginning of the contents of the new array. When
-            // we're done copying, we overwrite the full first word with
-            // the actual length of the slice.
+                // The first word of the slice result is potentially a partial
+                // word read from the original array. To read it, we calculate
+                // the length of that partial word and start copying that many
+                // bytes into the array. The first word we copy will start with
+                // data we don't care about, but the last `lengthmod` bytes will
+                // land at the beginning of the contents of the new array. When
+                // we're done copying, we overwrite the full first word with
+                // the actual length of the slice.
                 let lengthmod := and(_length, 31)
 
-            // The multiplication in the next line is necessary
-            // because when slicing multiples of 32 bytes (lengthmod == 0)
-            // the following copy loop was copying the origin's length
-            // and then ending prematurely not copying everything it should.
+                // The multiplication in the next line is necessary
+                // because when slicing multiples of 32 bytes (lengthmod == 0)
+                // the following copy loop was copying the origin's length
+                // and then ending prematurely not copying everything it should.
                 let mc := add(add(tempBytes, lengthmod), mul(0x20, iszero(lengthmod)))
                 let end := add(mc, _length)
 
                 for {
-                // The multiplication in the next line has the same exact purpose
-                // as the one above.
+                    // The multiplication in the next line has the same exact purpose
+                    // as the one above.
                     let cc := add(add(add(_bytes, lengthmod), mul(0x20, iszero(lengthmod))), _start)
                 } lt(mc, end) {
                     mc := add(mc, 0x20)
@@ -47,8 +55,8 @@ library BytesLib {
 
                 mstore(tempBytes, _length)
 
-            //update free-memory pointer
-            //allocating the array padded to 32 bytes like the compiler does now
+                //update free-memory pointer
+                //allocating the array padded to 32 bytes like the compiler does now
                 mstore(0x40, and(add(mc, 31), not(31)))
             }
             //if we want a zero-length slice let's just return a zero-length array
diff --git a/packages/vvisp-contracts/upgradeable/Proxy.sol b/packages/vvisp-contracts/upgradeable/Proxy.sol
index 86bbbc2..9efe9d8 100644
--- a/packages/vvisp-contracts/upgradeable/Proxy.sol
+++ b/packages/vvisp-contracts/upgradeable/Proxy.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.24;
+pragma solidity >=0.5.0 <0.6.0;
 
 
 /**
@@ -11,7 +11,7 @@ contract Proxy {
     * @dev Fallback function allowing to perform a delegatecall to the given implementation.
     * This function will return whatever the implementation call returns
     */
-    function() payable public {
+    function() external payable {
         address _impl = implementation();
         require(_impl != address(0));
 
diff --git a/packages/vvisp-contracts/upgradeable/UpgradeabilityProxy.sol b/packages/vvisp-contracts/upgradeable/UpgradeabilityProxy.sol
index 4cb71a6..e7aa840 100644
--- a/packages/vvisp-contracts/upgradeable/UpgradeabilityProxy.sol
+++ b/packages/vvisp-contracts/upgradeable/UpgradeabilityProxy.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.24;
+pragma solidity >=0.5.0 <0.6.0;
 
 import "./Proxy.sol";
 
diff --git a/packages/vvisp-contracts/upgradeable/VvispLibraryRegistry.sol b/packages/vvisp-contracts/upgradeable/VvispLibraryRegistry.sol
index d62fa14..1747654 100644
--- a/packages/vvisp-contracts/upgradeable/VvispLibraryRegistry.sol
+++ b/packages/vvisp-contracts/upgradeable/VvispLibraryRegistry.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.24;
+pragma solidity >=0.5.0 <0.6.0;
 
 import "openzeppelin-solidity/contracts/ownership/Ownable.sol";
 import "openzeppelin-solidity/contracts/math/SafeMath.sol";
@@ -11,7 +11,7 @@ contract VvispLibraryRegistry is Ownable {
     using BytesLib for bytes;
 
     event ProxyCreated(address _proxy, string _name);
-    event UpgradeAll(address[] _proxies, address[] _implementations);
+    event UpgradeAll(address payable[] _proxies, address[] _implementations);
     event UpgradeToAndCallData(bytes _data, uint256 _index, uint256 _length);
     event SetNonUpgradeable(address _address, string _name, string _fileName);
     event SetFileName(address _address, string _fileName);
@@ -34,7 +34,15 @@ contract VvispLibraryRegistry is Ownable {
     mapping(address => UpgradeableSet) public upgradeableSets;
     mapping(address => NonUpgradeableSet) public nonUpgradeableSets;
 
-    function setNonUpgradeables(address[] _addresses, string _names, uint256[] _nameLength, string _fileNames, uint256[] _fileNameLength) public onlyOwner {
+    function setNonUpgradeables(
+        address[] memory _addresses,
+        string memory _names,
+        uint256[] memory _nameLength,
+        string memory _fileNames,
+        uint256[] memory _fileNameLength
+    )
+        public onlyOwner
+    {
         require(_addresses.length != 0);
         require(_addresses.length == _nameLength.length);
         require(_addresses.length == _fileNameLength.length);
@@ -56,7 +64,7 @@ contract VvispLibraryRegistry is Ownable {
         }
     }
 
-    function updateFileNames(address[] _keyAddresses, string _fileNames, uint256[] _fileNameLength) public onlyOwner {
+    function updateFileNames(address[] memory _keyAddresses, string memory _fileNames, uint256[] memory _fileNameLength) public onlyOwner {
         require(_keyAddresses.length != 0);
         require(_keyAddresses.length == _fileNameLength.length);
 
@@ -75,14 +83,21 @@ contract VvispLibraryRegistry is Ownable {
         }
     }
 
-    function createProxy(string name) public onlyOwner {
+    function createProxy(string memory name) public onlyOwner {
         VvispProxy proxy = new VvispProxy();
         upgradeableKeyAddresses.push(address(proxy));
         upgradeableSets[address(proxy)].name = name;
         emit ProxyCreated(address(proxy), name);
     }
 
-    function upgradeToAndCalls(address[] _proxies, address[] _business, bytes _data, uint256[] _length) public onlyOwner {
+    function upgradeToAndCalls(
+        address payable[] memory _proxies,
+        address[] memory _business,
+        bytes memory _data,
+        uint256[] memory _length
+    )
+        public onlyOwner
+    {
         require(_proxies.length != 0);
         require(_proxies.length == _business.length);
         require(_proxies.length == _length.length);
diff --git a/packages/vvisp-contracts/upgradeable/VvispProxy.sol b/packages/vvisp-contracts/upgradeable/VvispProxy.sol
index 6a188d2..4a4a796 100644
--- a/packages/vvisp-contracts/upgradeable/VvispProxy.sol
+++ b/packages/vvisp-contracts/upgradeable/VvispProxy.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.24;
+pragma solidity >=0.5.0 <0.6.0;
 
 import "./UpgradeabilityProxy.sol";
 
@@ -70,10 +70,11 @@ contract VvispProxy is UpgradeabilityProxy {
      * @param data represents the msg.data to bet sent in the low level call. This parameter may include the function
      * signature of the implementation to be called with the needed payload
      */
-    function upgradeToAndCall(address implementation, bytes data) payable public onlyProxyOwner {
+    function upgradeToAndCall(address implementation, bytes memory data) public payable onlyProxyOwner {
         upgradeTo(implementation);
-        // solium-disable-next-line security/no-call-value
-        require(address(this).call.value(msg.value)(data));
+        // solium-disable-next-line security/no-low-level-calls
+        (bool success, ) = implementation.delegatecall(data);
+        require(success);
     }
 
     /**
diff --git a/packages/vvisp-utils/contracts/DependencyA.sol b/packages/vvisp-utils/contracts/DependencyA.sol
index ae50f79..6efafd9 100644
--- a/packages/vvisp-utils/contracts/DependencyA.sol
+++ b/packages/vvisp-utils/contracts/DependencyA.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.23;
+pragma solidity >=0.5.0 <0.6.0;
 
 
 contract DependencyA {
diff --git a/packages/vvisp-utils/contracts/DependencyB.sol b/packages/vvisp-utils/contracts/DependencyB.sol
index b1fe41b..c405c7f 100644
--- a/packages/vvisp-utils/contracts/DependencyB.sol
+++ b/packages/vvisp-utils/contracts/DependencyB.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.23;
+pragma solidity >=0.5.0 <0.6.0;
 
 
 contract DependencyB {
diff --git a/packages/vvisp-utils/contracts/DependencyD.sol b/packages/vvisp-utils/contracts/DependencyD.sol
index c312d02..1b6ae5d 100644
--- a/packages/vvisp-utils/contracts/DependencyD.sol
+++ b/packages/vvisp-utils/contracts/DependencyD.sol
@@ -1,10 +1,10 @@
-pragma solidity ^0.4.23;
+pragma solidity >=0.5.0 <0.6.0;
 
 
 contract DependencyD {
     uint[] integers;
     address token;
-    constructor(uint[] _integers, address _token) public {
+    constructor(uint[] memory _integers, address _token) public {
         integers = _integers;
         token = _token;
     }
diff --git a/packages/vvisp-utils/contracts/ErrorContract.sol b/packages/vvisp-utils/contracts/ErrorContract.sol
index b22a12d..84fa8cb 100644
--- a/packages/vvisp-utils/contracts/ErrorContract.sol
+++ b/packages/vvisp-utils/contracts/ErrorContract.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.0;
+pragma solidity >=0.5.0 <0.6.0;
 
 contract ErrorContract {
     function ErrorContract(){
diff --git a/packages/vvisp-utils/contracts/MyNFT.sol b/packages/vvisp-utils/contracts/MyNFT.sol
index 578aada..881bbe3 100644
--- a/packages/vvisp-utils/contracts/MyNFT.sol
+++ b/packages/vvisp-utils/contracts/MyNFT.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.24;
+pragma solidity >=0.5.0 <0.6.0;
 
 import 'openzeppelin-solidity/contracts/token/ERC721/ERC721Full.sol';
 import 'openzeppelin-solidity/contracts/token/ERC721/ERC721Mintable.sol';
diff --git a/packages/vvisp-utils/contracts/SecondB.sol b/packages/vvisp-utils/contracts/SecondB.sol
index a427f46..cfd47c2 100644
--- a/packages/vvisp-utils/contracts/SecondB.sol
+++ b/packages/vvisp-utils/contracts/SecondB.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.23;
+pragma solidity >=0.5.0 <0.6.0;
 
 
 contract SecondB {
diff --git a/packages/vvisp-utils/src/compile.js b/packages/vvisp-utils/src/compile.js
index 0b78eb7..e54b422 100644
--- a/packages/vvisp-utils/src/compile.js
+++ b/packages/vvisp-utils/src/compile.js
@@ -1,5 +1,5 @@
 module.exports = async function(filePath, options) {
-  const DEFAULT_COMPILER_VERSION = '0.4.24';
+  const DEFAULT_COMPILER_VERSION = '0.5.0';
 
   const fs = require('fs');
   const path = require('path');
diff --git a/packages/vvisp/contracts/test/Attachment.sol b/packages/vvisp/contracts/test/Attachment.sol
index 7912702..39c1ae2 100644
--- a/packages/vvisp/contracts/test/Attachment.sol
+++ b/packages/vvisp/contracts/test/Attachment.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.23;
+pragma solidity >=0.5.0 <0.6.0;
 
 import "openzeppelin-solidity/contracts/ownership/Ownable.sol";
 import "openzeppelin-solidity/contracts/math/SafeMath.sol";
@@ -32,8 +32,8 @@ contract Attachment is Ownable {
 
     function upsertAttachment(
         bytes32 _fileHash,
-        string _fileType,
-        string _fileName,
+        string memory _fileType,
+        string memory _fileName,
         uint256 _registrationDate) public onlyOwner
     {
         require(_fileHash != 0);
@@ -55,20 +55,20 @@ contract Attachment is Ownable {
         emit RemoveAttachment(_fileHash, beforeFileTypes, beforeFileNames, beforeRegistrationDate);
     }
 
-    function upsertFileType(bytes32 _fileHash, string _fileType) internal {
+    function upsertFileType(bytes32 _fileHash, string memory _fileType) internal {
         fileTypes[_fileHash] = _fileType;
     }
 
-    function removeFileType(bytes32 _fileHash) internal returns (string before) {
+    function removeFileType(bytes32 _fileHash) internal returns (string memory before) {
         before = fileTypes[_fileHash];
         delete fileTypes[_fileHash];
     }
 
-    function upsertFileName(bytes32 _fileHash, string _fileName) internal {
+    function upsertFileName(bytes32 _fileHash, string memory _fileName) internal {
         fileNames[_fileHash] = _fileName;
     }
 
-    function removeFileName(bytes32 _fileHash) internal returns (string before) {
+    function removeFileName(bytes32 _fileHash) internal returns (string memory before) {
         before = fileNames[_fileHash];
         delete fileNames[_fileHash];
     }
diff --git a/packages/vvisp/contracts/test/DependencyA.sol b/packages/vvisp/contracts/test/DependencyA.sol
index ae50f79..6efafd9 100644
--- a/packages/vvisp/contracts/test/DependencyA.sol
+++ b/packages/vvisp/contracts/test/DependencyA.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.23;
+pragma solidity >=0.5.0 <0.6.0;
 
 
 contract DependencyA {
diff --git a/packages/vvisp/contracts/test/DependencyB.sol b/packages/vvisp/contracts/test/DependencyB.sol
index 3254f03..b995a25 100644
--- a/packages/vvisp/contracts/test/DependencyB.sol
+++ b/packages/vvisp/contracts/test/DependencyB.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.23;
+pragma solidity >=0.5.0 <0.6.0;
 
 
 contract DependencyB {
diff --git a/packages/vvisp/contracts/test/DependencyC.sol b/packages/vvisp/contracts/test/DependencyC.sol
index bcbda84..664074d 100644
--- a/packages/vvisp/contracts/test/DependencyC.sol
+++ b/packages/vvisp/contracts/test/DependencyC.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.23;
+pragma solidity >=0.5.0 <0.6.0;
 
 
 contract DependencyC {
diff --git a/packages/vvisp/contracts/test/DependencyD.sol b/packages/vvisp/contracts/test/DependencyD.sol
index c312d02..1b6ae5d 100644
--- a/packages/vvisp/contracts/test/DependencyD.sol
+++ b/packages/vvisp/contracts/test/DependencyD.sol
@@ -1,10 +1,10 @@
-pragma solidity ^0.4.23;
+pragma solidity >=0.5.0 <0.6.0;
 
 
 contract DependencyD {
     uint[] integers;
     address token;
-    constructor(uint[] _integers, address _token) public {
+    constructor(uint[] memory _integers, address _token) public {
         integers = _integers;
         token = _token;
     }
diff --git a/packages/vvisp/contracts/test/Flattened.sol b/packages/vvisp/contracts/test/Flattened.sol
index f1dda78..88f3dee 100644
--- a/packages/vvisp/contracts/test/Flattened.sol
+++ b/packages/vvisp/contracts/test/Flattened.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.23;
+pragma solidity >=0.5.0 <0.6.0;
 
 
 contract Foo {
diff --git a/packages/vvisp/contracts/test/Loan.sol b/packages/vvisp/contracts/test/Loan.sol
index dcd5fa3..623d679 100644
--- a/packages/vvisp/contracts/test/Loan.sol
+++ b/packages/vvisp/contracts/test/Loan.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.23;
+pragma solidity >=0.5.0 <0.6.0;
 
 import "openzeppelin-solidity/contracts/ownership/Ownable.sol";
 import "openzeppelin-solidity/contracts/math/SafeMath.sol";
@@ -85,16 +85,16 @@ contract Loan is Ownable {
     */
     function upsertLoan(
         bytes32 _loanHash,
-        string _loanName,
+        string memory _loanName,
         uint256 _loanTypeCode,
         uint256 _loanAmount,
-        uint256[3] _rate,
+        uint256[3] memory _rate,
         uint256 _repaymentMethodCode,
-        uint256[2] _fundStartEndTime,
-        uint256[2] _loanStartEndDate,
+        uint256[2] memory _fundStartEndTime,
+        uint256[2] memory _loanStartEndDate,
         uint256 _repaymentNumber,
-        string _loanSummary,
-        string _detailHTML,
+        string memory _loanSummary,
+        string memory _detailHTML,
         uint256 _stateCode,
         uint256 _registrationDate)
     public onlyOwner
@@ -186,11 +186,11 @@ contract Loan is Ownable {
             beforeRegistrationDate);
     }
 
-    function upsertLoanName(bytes32 _loanHash, string _loanName) internal {
+    function upsertLoanName(bytes32 _loanHash, string memory _loanName) internal {
         loanNames[_loanHash] = _loanName;
     }
 
-    function removeLoanName(bytes32 _loanHash) internal returns (string before) {
+    function removeLoanName(bytes32 _loanHash) internal returns (string memory before) {
         before = loanNames[_loanHash];
         delete loanNames[_loanHash];
     }
@@ -294,20 +294,20 @@ contract Loan is Ownable {
         delete repaymentNumbers[_loanHash];
     }
 
-    function upsertLoanSummary(bytes32 _loanHash, string _loanSummary) internal {
+    function upsertLoanSummary(bytes32 _loanHash, string memory _loanSummary) internal {
         loanSummaries[_loanHash] = _loanSummary;
     }
 
-    function removeLoanSummary(bytes32 _loanHash) internal returns (string before) {
+    function removeLoanSummary(bytes32 _loanHash) internal returns (string memory before) {
         before = loanSummaries[_loanHash];
         delete loanSummaries[_loanHash];
     }
 
-    function upsertDetailHTML(bytes32 _loanHash, string _detailHTML) internal {
+    function upsertDetailHTML(bytes32 _loanHash, string memory _detailHTML) internal {
         detailHTMLs[_loanHash] = _detailHTML;
     }
 
-    function removeDetailHTML(bytes32 _loanHash) internal returns (string before) {
+    function removeDetailHTML(bytes32 _loanHash) internal returns (string memory before) {
         before = detailHTMLs[_loanHash];
         delete detailHTMLs[_loanHash];
     }
diff --git a/packages/vvisp/contracts/test/Portfolio.sol b/packages/vvisp/contracts/test/Portfolio.sol
index 8197241..1c9e5e2 100644
--- a/packages/vvisp/contracts/test/Portfolio.sol
+++ b/packages/vvisp/contracts/test/Portfolio.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.23;
+pragma solidity >=0.5.0 <0.6.0;
 
 import "openzeppelin-solidity/contracts/ownership/Ownable.sol";
 import "openzeppelin-solidity/contracts/math/SafeMath.sol";
@@ -29,11 +29,11 @@ contract Portfolio is Ownable {
         _initialized = true;
     }
 
-    function loanHash(bytes32 _portfolioHash) view public returns (bytes32[] _loanHash) {
+    function loanHash(bytes32 _portfolioHash) public view returns (bytes32[] memory _loanHash) {
         return _loanHashs[_portfolioHash];
     }
 
-    function upsertPortfolio(bytes32 _portfolioHash, bytes32[] _loanHash, uint256 _registrationDate) public onlyOwner {
+    function upsertPortfolio(bytes32 _portfolioHash, bytes32[] memory _loanHash, uint256 _registrationDate) public onlyOwner {
         require(_portfolioHash != 0);
 
         upsertLoanHash(_portfolioHash, _loanHash);
@@ -51,11 +51,11 @@ contract Portfolio is Ownable {
         emit RemovePortfolio(_portfolioHash, beforeLoanHash, beforeRegistrationDate);
     }
 
-    function upsertLoanHash(bytes32 _portfolioHash, bytes32[] _loanHash) internal {
+    function upsertLoanHash(bytes32 _portfolioHash, bytes32[] memory _loanHash) internal {
         _loanHashs[_portfolioHash] = _loanHash;
     }
 
-    function removeLoanHash(bytes32 _portfolioHash) internal returns (bytes32[] _before) {
+    function removeLoanHash(bytes32 _portfolioHash) internal returns (bytes32[] memory _before) {
         _before = _loanHashs[_portfolioHash];
         delete _loanHashs[_portfolioHash];
     }
diff --git a/packages/vvisp/contracts/test/SecondA.sol b/packages/vvisp/contracts/test/SecondA.sol
index 8b9c97c..5e299a8 100644
--- a/packages/vvisp/contracts/test/SecondA.sol
+++ b/packages/vvisp/contracts/test/SecondA.sol
@@ -1,16 +1,16 @@
-pragma solidity ^0.4.23;
+pragma solidity >=0.5.0 <0.6.0;
 
 
 contract SecondA {
     address addressB;
     address addressC;
 
-    constructor(address _addressB, address _addressC, address[] _owners) public {
+    constructor(address _addressB, address _addressC, address[] memory _owners) public {
         addressB = _addressB;
         addressC = _addressC;
     }
 
-    function initialize(address _token, address _owner, address[] _addressA) public {
+    function initialize(address _token, address _owner, address[] memory _addressA) public {
         // something
     }
 }
diff --git a/packages/vvisp/contracts/test/SecondB.sol b/packages/vvisp/contracts/test/SecondB.sol
index a427f46..cfd47c2 100644
--- a/packages/vvisp/contracts/test/SecondB.sol
+++ b/packages/vvisp/contracts/test/SecondB.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.23;
+pragma solidity >=0.5.0 <0.6.0;
 
 
 contract SecondB {
diff --git a/packages/vvisp/contracts/test/SecondC.sol b/packages/vvisp/contracts/test/SecondC.sol
index 93ecc07..d53518f 100644
--- a/packages/vvisp/contracts/test/SecondC.sol
+++ b/packages/vvisp/contracts/test/SecondC.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.23;
+pragma solidity >=0.5.0 <0.6.0;
 
 
 contract SecondC {
diff --git a/packages/vvisp/contracts/test/SecondD.sol b/packages/vvisp/contracts/test/SecondD.sol
index 2f03ac3..f0ed22a 100644
--- a/packages/vvisp/contracts/test/SecondD.sol
+++ b/packages/vvisp/contracts/test/SecondD.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.23;
+pragma solidity >=0.5.0 <0.6.0;
 
 
 contract SecondD {
diff --git a/packages/vvisp/contracts/test/Token_V0.sol b/packages/vvisp/contracts/test/Token_V0.sol
index e6300bf..3e7a2d8 100644
--- a/packages/vvisp/contracts/test/Token_V0.sol
+++ b/packages/vvisp/contracts/test/Token_V0.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity >=0.5.0 <0.6.0;
 
 import "openzeppelin-solidity/contracts/ownership/Ownable.sol";
 import "openzeppelin-solidity/contracts/math/SafeMath.sol";
@@ -82,6 +82,6 @@ contract Token_V0 is Ownable {
     function mint(address to, uint256 value) public onlyOwner {
         _balances[to] = _balances[to].add(value);
         _totalSupply = _totalSupply.add(value);
-        emit Transfer(0x0, to, value);
+        emit Transfer(address(0), to, value);
     }
 }
diff --git a/packages/vvisp/contracts/test/Token_V1.sol b/packages/vvisp/contracts/test/Token_V1.sol
index 8885d03..7543bc9 100644
--- a/packages/vvisp/contracts/test/Token_V1.sol
+++ b/packages/vvisp/contracts/test/Token_V1.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity >=0.5.0 <0.6.0;
 
 import "./Token_V0.sol";
 
diff --git a/packages/vvisp/contracts/upgradeable/VvispRegistry.sol b/packages/vvisp/contracts/upgradeable/VvispRegistry.sol
index efd5715..6d5726a 100644
--- a/packages/vvisp/contracts/upgradeable/VvispRegistry.sol
+++ b/packages/vvisp/contracts/upgradeable/VvispRegistry.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.24;
+pragma solidity >=0.5.0 <0.6.0;
 
 import "@haechi-labs/vvisp-contracts/upgradeable/VvispLibraryRegistry.sol";
 
diff --git a/packages/vvisp/referenceFiles/contracts/Migrations.sol b/packages/vvisp/referenceFiles/contracts/Migrations.sol
index e45c0ec..fc14cdd 100644
--- a/packages/vvisp/referenceFiles/contracts/Migrations.sol
+++ b/packages/vvisp/referenceFiles/contracts/Migrations.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.24;
+pragma solidity >=0.5.0 <0.6.0;
 
 
 contract Migrations {
diff --git a/packages/vvisp/referenceFiles/package.json b/packages/vvisp/referenceFiles/package.json
index a39fdb9..21b3432 100644
--- a/packages/vvisp/referenceFiles/package.json
+++ b/packages/vvisp/referenceFiles/package.json
@@ -23,7 +23,7 @@
     "ganache-cli": "6.1.0",
     "husky": "^1.2.1",
     "lint-staged": "^8.1.0",
-    "openzeppelin-solidity": "2.0.0",
+    "openzeppelin-solidity": "^2.1.0",
     "prettier": "^1.15.3",
     "solidity-coverage": "git+https://github.com/rotcivegaf/solidity-coverage.git#5875f5b7bc74d447f3312c9c0e9fc7814b482477",
     "solium": "^1.1.6",
diff --git a/packages/vvisp/referenceFiles/truffle-config.js b/packages/vvisp/referenceFiles/truffle-config.js
index 62fb8ed..fdba833 100644
--- a/packages/vvisp/referenceFiles/truffle-config.js
+++ b/packages/vvisp/referenceFiles/truffle-config.js
@@ -39,13 +39,13 @@ module.exports = {
   },
   compilers: {
     solc: {
-      version: '0.4.24',                
+      version: '0.5.0',
       settings: {
         optimizer: {
           enabled: true,
-          runs: 200   
+          runs: 200
         },
-        evmVersion: 'byzantium' 
+        evmVersion: 'byzantium'
       }
     }
   },