diff --git a/contracts/drafts/ERC1046/TokenMetadata.sol b/contracts/drafts/ERC1046/TokenMetadata.sol
index 6efb4ed72..31fe31029 100644
--- a/contracts/drafts/ERC1046/TokenMetadata.sol
+++ b/contracts/drafts/ERC1046/TokenMetadata.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 import "../../token/ERC20/IERC20.sol";
 
diff --git a/contracts/mocks/ERC20WithMetadataMock.sol b/contracts/mocks/ERC20WithMetadataMock.sol
index e42e46f96..c7ad978f8 100644
--- a/contracts/mocks/ERC20WithMetadataMock.sol
+++ b/contracts/mocks/ERC20WithMetadataMock.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.21;
+pragma solidity ^0.4.24;
 
 import "../token/ERC20/ERC20.sol";
 import "../drafts/ERC1046/TokenMetadata.sol";
diff --git a/contracts/payment/ConditionalEscrow.sol b/contracts/payment/ConditionalEscrow.sol
index 9278a69a3..7108911b5 100644
--- a/contracts/payment/ConditionalEscrow.sol
+++ b/contracts/payment/ConditionalEscrow.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.23;
+pragma solidity ^0.4.24;
 
 import "./Escrow.sol";
 
diff --git a/contracts/payment/Escrow.sol b/contracts/payment/Escrow.sol
index dc3fbfef5..ca0c124d7 100644
--- a/contracts/payment/Escrow.sol
+++ b/contracts/payment/Escrow.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.23;
+pragma solidity ^0.4.24;
 
 import "../math/SafeMath.sol";
 import "../ownership/Ownable.sol";
diff --git a/contracts/payment/RefundEscrow.sol b/contracts/payment/RefundEscrow.sol
index 802dd4711..884494f1a 100644
--- a/contracts/payment/RefundEscrow.sol
+++ b/contracts/payment/RefundEscrow.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.23;
+pragma solidity ^0.4.24;
 
 import "./ConditionalEscrow.sol";
 import "../ownership/Ownable.sol";