32-bit apps. I have 32-bit apps where the developer is either gone or will not update, thus if I wish to keep using these I have to stay on Mojava. This applies to four Macs which will likely never move away from Mojava.
- software for a "smart pen" where the company went out of business
- some label printing software
- some Steam games
- some games from GOG
Even if I don't run these daily, I don't like to be cut off from my past.
Still get a regular trickle of emails from schools complaining about it. I tell them to call Cupertino.
It also did not break OpenGL, only deprecate it. macOS is still stuck on a many-years-old version of OpenGL, but what worked in the past continues to work. Even Apple Silicon Macs will support it.