The badge notification is because he wants me to go to Catalina. I never want to upgrade to Catalina because my hardware is too old to perform under a newer version of MacOS than I already have.
How can I reject this notification or have the notification badge disappear?
I've tried System Preferences -> Notifications, to see if I could turn off all badge notifications from the System Preferences application, but that does not seem to be an option. And really, I do not want to disable all System Preferences notifications, I just want to tell him to stop harassing me about Catalina's upgrade.