Originally Posted by Ira L
By "previous version of MacOS" do you mean going from say, MacOS 12 to MacOS 11; or from something like MacOS 11.3 to MacOS 11.2? Or does it apply to both situations?
Definitely macOS 12 to macOS 11, I don’t know for sure about macOS 11.4 to 11.3. In the first case there are incompatibilities in apps, data, backups, etc. that make reverting very difficult, and that can include firmware updates as well. In line with that, I have just learned the hard way there are situations that can cannot be recovered, even with the aid of a second computer, Apple Configurater 2, and DFU mode. My M1 mini is now in the hands of the Genius Bar. Say yes to AppleCare!


If we knew what it was we were doing, it wouldn't be called research, would it?

— Albert Einstein