[pydave]

Unity 5 came out in 2017 and it's not supported on Catalina.[1]

So devs of two year old games will need an old macOS install that can export their game to 64-bit, but also a new enough macOS install that can notarize their app (maybe these can both be Mojave -- but many indies don't own their own macs).

Also, Unity 5 is no longer available for purchase. If they're already using their license on another machine, they'll have to migrate it to these macOS installs.

Devs could upgrade to a more recent Unity and fix all the bugs, but to what benefit and at what cost?

[1]: https://forum.unity.com/threads/installing-unity-on-macos-ca...