Is there a way to disable update notifications in Mojave?
If you want to disable updates for specific apps, you can use softwareupdate --ignore.

Do all the following in Terminal

Start with

softwareupdate -l


to list all available updates,

defaults read /Library/Preferences/com.apple.SoftwareUpdate.plist


to find the Identifier of the app you want to ignore, and then

softwareupdate --ignore 'Identifier'


to ignore the update. Should disappear from Software Updates in System Preferences immediately.