I just checked the App Store for updates. As expected, there were updates for several apps in order to add Big Sur support:
I clicked the “Update All” button to be informed “GarageBand can’t be installed on … because macOS version 11 or later is required.”
Seriously? Big Sur just shipped yesterday and Apple has already made a flagship app incompatible with everything else?
And why is it being presented on my list of updates if it’s incompatible? In the past, the App Store would never show incompatible updates.
This is absolutely shameless self-promotion. If they think this is somehow going to convince people to upgrade their comptuers to a new and untested operating system, they’re completely nuts.
UPDATE: Further investigation (see comments below) indicates that this was a mistake, not an intent to drop support for GarageBand on macOS versions 10.*. But at this time (November 17, 2020), the mistake has not yet been corrected.