I have been using Parallels Desktop to run old but still useful/essential software on a MacOS 10.13.6 VM because it will not run on a newer MacOS. And now that I have upgraded to Big Sur on an M1 iMac, that MacOS 10.13.6 VM is flagged as incompatible (after I have also paid for an upgrade to Parallels Desktop ... which now no longer serves the purpose for which I originally bought it). So, I am now eagerly awaiting an upgrade to Parallels Desktop on which I will be able once again to run my legacy Mac software on my MacOS 10.13.6 VM.