Installing older pro apps (Motion) messes up High Sierra?

I used my install disc for Motion 4 (part of Final Cut 7) and did an install on my Mac Mini that is at OS X High Sierra. It took lots of time writing files and so forth, but of course when I tried to launch it an alert box said I would need to upgrade to run it on this machine.

Probably due to library file writes and so forth that have set my Mac Mini back in time in some respects, I am now getting a Software Update available that is "Pro Apps Uncompressed 4:2:2 Codec v1.0.2" and "enables viewing of... in newer video applications on OS X Mavericks."

I'm not saying I'm smart to have attempted this (I use my "cheese grater" Mac at an older OS X for my Pro Apps stuff), but I didn't think it would hurt anything.

Any opinions on proceeding? Important enough to restore back to right after I did the High Sierra upgrade? If not, any way to say "never - go away" to Software Updates that are obviously old?

thanks