This is a question that has troubled me for a while. Most other upgrades replace the previous versions. You get all the new sounds and features without having to replace instruments and find or recreate presets.(which can become very nerve racking and tedious). Session Drummer, Z3ta+, Rapture/Dimension, Etc all upgrade as separate and new instruments. Anyone else bothered by this?

Good point - I've also had a few hunting parties sent out to find old sounds...

At least it avoids nightmares like the ezdrummer 2 release.

I wonder what happens if you use the Command Center on those you mentioned.  Does it upgrade them - or just install the new version alongside the older one?  If it upgrades it, then there's your answer -- use the Command Center.

It doesn't upgrade.