It wouldn’t cost Homebrew folks much to add a flag to skip dependency version checking which would solve most issues with using older macOS. But they don’t want to, and have closed all issues asking for it as wontfix.
Seems like good enough a reason for them not to do it.
Their tooling is open-source, surely the few people still using unmaintained versions of macOS can create a `LegacyHomeBrew/brew` repository with patches for old macOS versions? It would also be a good place to stuff all the patches and workarounds that may be necessary to support old macOS versions.
They said they don’t want that [1]. It’s not just me, several people have asked for it. Maintaining an extra fork just for that is also out of the question for most people.
