Windows users, beware! This is in tech specs, but not in the free upgrade email ad, and nowhere on the upgrade path (which may include logging in from a second browser if your primary one is not Chrome), so chances are you will get there not noticing that Studio One 5 runs on Windows 10 ONLY. As I, a W8.1 user, just did. And yes, surely, same goes about Sphere.
Well, since it's free, there's nothing to complain about. I just have it in my account, and probably at some point later I'll upgrade my PC and will finally have a chance to use all those killer features (scenes, scoring... you name it). The biggest downside is that I won't be able to collaborate with anyone who's going to upgrade unless they'll keep working in version 4 specially for me - until I upgrade my OS (i.e. laptop).
I think since such compatibility issues are going to arise for pre-W10 users, the end of support for earlier versions of Windows should be there IN BIG LETTERS in all advertising materials. I guess when version 4 went 64-bit only, it was properly announced, and ideas for bridging the good old 32-bit VSTs were suggested for those who still needed them. This time, there is no bridging solution, so take that into consideration if you or some of your collaborators are on pre-W10.