What is the rationale for freezing the Solidity version?

[lilyanB]

Hello
I've seen that all interfaces have been moved to ^0.8.0 but not contracts. This would make it possible to use them when importing
change this: pragma solidity 0.8.17
to this: pragma solidity ^0.8.17;
I can do it if needed

[hensha256]

The core contract is frozen in version for security reasons - that is the version of solidity that it is audited for. However the interfaces are made to be variable versions so that you can integrate with Permit2 in your codebase. Why is it you need to import Permit2.sol and not just use IPermit2.sol?

[lilyanB]

We need to use Permit2.sol for testing purposes. Right now, we have to fork ETH mainnet to have the contract already deployed so we can use only IPermit2.sol