Anytime I go to open an older project in my DAW, I'm presented with a dialog that I no longer have Pianoteq 3 because I've updated to version 4. A mild inconvenience, but it would be nice to keep the name the same across version changes. I think your users are intelligent enough to know what version they have or at least be able to figure it out.
i voted "Yes", becuse it's important to keep older versions beside the new ones,
because, even with same presets, same parameters, the physical model changes between versions, so that, there is some little, but audible differences.
Try to play a music with same parameters, and you'll not hear the same.
Try to doing manual corrections to find again the sound is hardly not possible, even with time.
Then, for some musics, i keep older versions,
when some other musics will grow with newer version sound !
Noone can predict which and why, because only some experimental thing.
So it is a safe choice from Modartt to let the user to do manual switchings between plugin versions.
Well, is the problem more that the installation procedure, by default, overwrites the old version with the new version? This arrangement is logical (or we would end up with many versions of the program) but it does create the situation that you describe.
Should there be a choice given during installation (overwrite or create new folder) with a warning that overwriting the program will mean that sequences created with the previous version will need to be updated and will sound different?