What Software will I lose by reverting back to Mojave?

[BruceCNY]

I'm planning to purchase another 27 imac for my design studio. Currently, my entire studio (several Imacs, MacBook Pro, etc.) are running older versions of MacOS. Most of my software is Adobe CS6 suite and runs well on all my machines. The new Imacs come loaded with Catalina. I know I can go back to Mojave before loading all my software but what new features will I be losing? I don't want to have to purchase CC Cloud software at this time.
Thanks.

 

[MacClueless]

Installing over won'tose anything though you'll probably have to do it from an external or USB.