I figured since people here use MacOS and also like obscure old software for audio fuckery, then it's really important to note that if you update to Catalina, all your old 32 bit apps will stop working.
It seems that this applies to all apps that give you a "this app is not optimized for your Mac" warning.
I occasionally get this stuff when opening MOTU software and Ableton Live, so it's probably going to mess a lot of stuff up.
More on this here https://www.macrumors.com/guide/32-bit-mac-apps/