Update to MacOS Catalina 10.15 to accommodate/use of GoodNotes 5

Check compatibility: macOS Catalina is compatible with these computers - Apple Support

If it is, Open in Safari: https://itunes.apple.com/us/app/macos-catalina/id1466841314?ls=1&mt=12

Also check with the Goodnotes developer before upgrading. If they have not updated their app to 64-bit, it will not run on Catalina, but should run on Mojave 10.14.

This third-party web page show GoodNotes 5.X working with both Catalina and Big Sur, but it is based on user feedback, not developers' knowledge.

https://roaringapps.com/app/goodnotes