We know you want to play with the new features, but Catalina is not something you should install right away. Apple changed the operating system in some fundamental ways that could break your essential apps or workflows.
32-bit apps don’t run anymore: To identify which 32-bit apps—and portions of apps—won’t work in Catalina, download and run the free Go64 utility from St. Clair Software. If you rely on any of the software it calls out, you’ll need to update or find an alternative.
Newly installed apps must be notarized by Apple: Notarization is a process Apple uses to verify that an app distributed outside the Mac App Store is free of malware. It’s likely that older apps already on your Mac when you upgrade will continue to work fine, but if you try to install an older, unnotarized app, that may not work.
Apps require more permissions than before: In the last few versions of macOS, you’ve probably seen apps asking for permission to do things like access data in Contacts, Calendars, and Photos. In Catalina, apps will have to ask for permission to access files in your Desktop and Documents folders, and external volumes. It’s possible that older software won’t understand.
We suggest you wait for the 10.15.3 or 10.15.4 update, or get in touch with us early in 2020 for a status update.