shouldn't make an app unusable with an upgrade when you can't upgrade other devices - (Mac OS)

You were warned when you pressed the upgrade button in reminders that it would not work with your Mac until and unless you upgraded it to macOS Catalina, which will be available in October, and were given the opportunity to cancel the update at the time.

Supposedly it showed such a warning before the upgrade.

I always wait a week to a month or more to even Update, moreso with Upgrades, just to to se if there are problems... which of late seems more often than not. :(