[ashlar]

Ok, I have briefly checked the new build. There is now an option to browse multiple versions similar to what happens for Movie Sets. It's found under Settings/Media/Videos/Show video with multiple versions as folder.

There is still some "differences" in how content is presented, for instance there is no managing the single versions as you can do for Movie Sets entries (choosing art, etc.). One can handle those things in the "regular" movie versions dialog but, maybe for future releases, I think it would be better to have a unified, coherent way of presenting content between Movie Sets and Movie Versions. Without going into which way is better, Movie Sets is an established feature and I think people are by now used to it and to how it works. Expectations of Movie Versions to behave similarly are, I think, understandable.
But, again, this can be for the future, if devs are ok with the way things stand now for Movie Versions. I surely wouldn't object.

Something which I don't know if it's a bug or me not understanding how things work: once I add multiple versions of a movie (in my case 1080 and 4K versions), I can't seem to be able to access online artwork that was previously available when the two versions were separate movies. If I invoke the Manage/Movie Version dialog and go to "Choose Art", Kodi tells me there is no art available and the only option I have is to browse for local art.

Lastly, I think there's some performance issues with this build. When entering and exiting the Movie Version dialogs there is a one/two seconds delay where Kodi displays the "rotating wheel" (or whatever it is, the equivalent of the old Windows hourglass). I don't get that if I display Movie Versions with the regular dialog, only if I select the option to display movie versions as folder.

Thanks a lot @XODIDOX for all the work you put into this!