That depends on your Mac. The older the Mac, the older the version. On most M1 Macs, you can go back even to Big Sur, on M2 it’s usually Monterey and so on. It might be different with the Pro/Max/Ultra variants though.
I believe brew dropped support for a high Sierra just a couple years back (2022 I think) but as of now my 2012 MacBook Pro is still chugging along whenever I need to compile or test something for x86 and can’t be bothered to cross-compile from my new MacBook :)
What’s the oldest version of MacOS that I could reinstall on Apple silicon?
That depends on your Mac. The older the Mac, the older the version. On most M1 Macs, you can go back even to Big Sur, on M2 it’s usually Monterey and so on. It might be different with the Pro/Max/Ultra variants though.
More important question for me:
what is the oldest MacOS with xcode support (and therefore oldest I can run brew on)?
I keep meaning to figure this out.
I believe brew dropped support for a high Sierra just a couple years back (2022 I think) but as of now my 2012 MacBook Pro is still chugging along whenever I need to compile or test something for x86 and can’t be bothered to cross-compile from my new MacBook :)