if you don’t want to update to macOS Catalina, and you don’t want Software Update bugging you about it, just run this in your terminal:
sudo softwareupdate --ignore "macOS Catalina"
reverse it > Yes, you just have to run sudo softwareupdate --reset-ignored
from @mistydemeo on twitter
@ecksmc
yep
this sort of works.
But will not remove the red badge.
You can remove it. but it will come back.
so write a small cron job to kill the red badge.
see:
https://robservatory.com/remove-the-macos-catalina-guilt-trip-from-macos-mojave/