Running 2 Systems (Mojave and High Sierra)

[GJWarch]

I am running High Sierra and Mojave on my hard drive in different volumes. I want both to be available for running AC.
I am currently running AC 22 and 23 in High Sierra. How do I run them in Mojave? I have installed Mojave as a volume on my SSD. AC 22 doesn't allow it to load. I have put the software key into the office pool. Can I only download AC 22 to one drive? How does the software key fit into all of this?
Can I simply drag and drop AC programs and files from one system to the other? (That sounds too easy!)
Thank you in advance... I am so close and so far away!

Greg

[Ralph Wessel]

Most things can just be copied from one to the other, e.g. macOS applications are supposed to be drag/drop installs. All files can be copied from one to another without problems.

But anything requiring a 3rd-party driver will be an exception, and that includes the software for a hardware key (and possibly a software key too). Generally you can find an installer just for the driver (on either OS version), so it shouldn't be a problem.

I use Parallels Desktop for running previous OS versions, so I don't need to reboot to run older versions. It works well.