FWIW -
I downloaded the Studio upgrade from Celemony's site.
(All editions are available there.)
A careful re-read of their instructions on the site recommended a clean install...
After uninstalling previous versions, and installing the new version, Sonar found it and
it still works as expected via ARA, and the VST3 plugin versions are there as well! Nice.
Now, if I can just get the stand-alone version to run, I'll be happy!