I have no plans to move my main iMac to macOS Catalina, at least for the forseeable future. There are two key apps I use—Fujitsu’s ScanSnap scanner software and the Many Tricks’ accounting app—that are both 32-bit. In addition, there are changes in Catalina relative to permissions that make it somewhat Vista like and slow down my interaction with the system.
There are two things that I wanted to get rid of on my iMac: The notice about Catalina, and the infuriating red dot. At its simplest level, this appears to require just two Terminal commands
This is (yet another) example of Apple’s parochial insistence that “We Know Better.” There’s no reason this notification and popup should not be able to be permanently dismissed.