How to turn off prompt to upgrade to Catalina Software Update notification?

I've just received a notification from Software Update to upgrade to Catalina in the same manner I've always received updates to the current OS. Before Mojave the notifications to upgrade OS would come through the App Store but now it is through the Software Update.

I cannot upgrade because I've been notified by several software vendors whose software I depend upon that they are not able to run on Catalina so I will need to hold off for some time to come. Until then, is there a way to turn off this notification or am I stuck with seeing the red 1 hanging over the System Preferences on the Dock until I do?

FTR, I've disabled all the check marks in the Advanced area of the Software Update and rebooted but the "red 1" persists over the icon. I hope this isn't Apple trying a hard sell on upgrading before I am ready to.