my question is:

How can I update the already compiled contracts to version 0.8? or how can I make address not give me an error with version 0.7?

i did trying until it worked out.
Otherwise, here's the breaking changes to follow
https://docs.soliditylang.org/en/v0.8.13/080-breaking-changes.html

there will be reasons why you want to have multiple solidity versions in project, in that case use hardhat

thanks!