Submitted by shw, also found by 0xRajeev and JMukesh
Some contracts (e.g., PrizePool) use an unlocked pragma (e.g., pragma solidity >=0.6.0 <0.7.0;) which is not fixed to a specific Solidity version. Locking the pragma helps ensure that contracts do not accidentally get deployed using a different compiler version with which they have been tested the most.
Please use grep -R pragma . to find the unlocked pragma statements.
Recommend locking pragmas to a specific Solidity version. Consider the compiler bugs in the following lists and ensure the contracts are not affected by them. It is also recommended to use the latest version of Solidity when deploying contracts (see Solidity docs).
Solidity compiler bugs:
Solidity repo - known bugs
Solidity repo - bugs by version
kamescg (PoolTogether) confirmed:
