diff --git a/contracts/Migrations.sol b/contracts/Migrations.sol
index 58f56b4..730f7f3 100644
--- a/contracts/Migrations.sol
+++ b/contracts/Migrations.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.8;
+pragma solidity 0.6.8;
 
 contract Migrations {
   address public owner;
diff --git a/contracts/metatx/ERC20Fees.sol b/contracts/metatx/ERC20Fees.sol
index d9870d0..0973452 100644
--- a/contracts/metatx/ERC20Fees.sol
+++ b/contracts/metatx/ERC20Fees.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.8;
+pragma solidity 0.6.8;
 
 import "@openzeppelin/contracts/math/SafeMath.sol";
 import "@openzeppelin/contracts/GSN/GSNRecipient.sol";
diff --git a/contracts/mocks/token/ERC20/ERC20MetaMock.sol b/contracts/mocks/token/ERC20/ERC20MetaMock.sol
index d3e8655..5ec2d27 100644
--- a/contracts/mocks/token/ERC20/ERC20MetaMock.sol
+++ b/contracts/mocks/token/ERC20/ERC20MetaMock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.8;
+pragma solidity 0.6.8;
 
 import "../../../metatx/ERC20Fees.sol";
 import "../../../token/ERC20/ERC20.sol";
diff --git a/contracts/mocks/token/ERC20/ERC20Mock.sol b/contracts/mocks/token/ERC20/ERC20Mock.sol
index fe1162e..5b649f3 100644
--- a/contracts/mocks/token/ERC20/ERC20Mock.sol
+++ b/contracts/mocks/token/ERC20/ERC20Mock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.8;
+pragma solidity 0.6.8;
 
 import "../../../token/ERC20/ERC20.sol";
 
diff --git a/contracts/mocks/token/ERC20/ERC20WithOperatorsMock.sol b/contracts/mocks/token/ERC20/ERC20WithOperatorsMock.sol
index 001a242..dbee199 100644
--- a/contracts/mocks/token/ERC20/ERC20WithOperatorsMock.sol
+++ b/contracts/mocks/token/ERC20/ERC20WithOperatorsMock.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.8;
+pragma solidity 0.6.8;
 
 import "../../../token/ERC20/ERC20WithOperators.sol";
 
diff --git a/contracts/token/ERC20/ERC20.sol b/contracts/token/ERC20/ERC20.sol
index a05a2a3..c6e31ed 100644
--- a/contracts/token/ERC20/ERC20.sol
+++ b/contracts/token/ERC20/ERC20.sol
@@ -27,7 +27,7 @@ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.8;
+pragma solidity 0.6.8;
 
 import "@openzeppelin/contracts/GSN/Context.sol";
 import "@openzeppelin/contracts/introspection/ERC165.sol";
diff --git a/contracts/token/ERC20/ERC20WithOperators.sol b/contracts/token/ERC20/ERC20WithOperators.sol
index d170750..09f68ba 100644
--- a/contracts/token/ERC20/ERC20WithOperators.sol
+++ b/contracts/token/ERC20/ERC20WithOperators.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.8;
+pragma solidity 0.6.8;
 
 import "@animoca/ethereum-contracts-core_library/contracts/access/WhitelistedOperators.sol";
 import "./ERC20.sol";
diff --git a/contracts/token/ERC20/IERC20.sol b/contracts/token/ERC20/IERC20.sol
index 12700d9..259734d 100644
--- a/contracts/token/ERC20/IERC20.sol
+++ b/contracts/token/ERC20/IERC20.sol
@@ -27,7 +27,7 @@ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.8;
+pragma solidity 0.6.8;
 
 /**
  * @dev Interface of the ERC20 standard as defined in the EIP.
diff --git a/contracts/token/ERC20/IERC20Allowance.sol b/contracts/token/ERC20/IERC20Allowance.sol
index 34ba946..ccf5ddd 100644
--- a/contracts/token/ERC20/IERC20Allowance.sol
+++ b/contracts/token/ERC20/IERC20Allowance.sol
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.8;
+pragma solidity 0.6.8;
 
 /**
  * @dev Interface for additional ERC20 allowance features
diff --git a/contracts/token/ERC20/IERC20Detailed.sol b/contracts/token/ERC20/IERC20Detailed.sol
index 73df2fd..2123643 100644
--- a/contracts/token/ERC20/IERC20Detailed.sol
+++ b/contracts/token/ERC20/IERC20Detailed.sol
@@ -27,7 +27,7 @@ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 // SPDX-License-Identifier: MIT
 
-pragma solidity ^0.6.8;
+pragma solidity 0.6.8;
 
 /**
  * @dev Interface for commonly used additional ERC20 interfaces