Catalina is here. It fixes many things, among them iTunes. On the other hand, it drops support for 32-Bit MacOS applications.

Consider the upgrade carefully.

$ system_profiler SPApplicationsDataType
…
    Steam:

      Version: 1.5
      Obtained from: Identified Developer
      Last Modified: 23.08.16, 20:32
      Kind: Intel
      64-Bit (Intel): No
      Signed by: Developer ID Application: Valve Corporation, Developer ID Certification Authority, Apple Root CA
      Location: /Applications/Steam.app
…

Anything listed with 64-Bit (Intel): No will stop working after the upgrade. Check before you upgrade, and consider what you will be losing access to if you perform the upgrade.

On my box:

• Apprentice Alf DeDRM Plugin for Calibre
• Civilization V
• CoverScout 3
• Google Music Manager
• Google Photos Backup
• GrandPerspective
• JD-GUI
• Kindle (1.23.1, locked from upgrades)
• Mathematica
• Microsoft Office
• SongGenie 2
• Steam
• TigerVNC
• UnRarX

Some of them are unimportant, other things are quite critical, some of them can’t be updated easily.

At this point, for me this is a hard pass, and a lot of work to be done.