if your project is managed by composer you just set your compatible php version and you’re set. the 5.6 to 7 conversion was painless for most because 7 was largely backwards incompatible. I did it for a 300kloc 10 year old codebase in a few days. After that the breaking changes have been pretty easy to manage, and many users are still on 7.4. 8 is where things have really started to change but still the process is not that hard.