I thought that it was touched on in this forum a while back, but can’t find the post. There was an upgrade pricing path for the previous versions of BFD (v1.5 to 2 and 2 to 3). Sure different ownership, or parent company now, so inMusic could say, screw you, pay full price for existing BFD3 owners, but I feel pretty confident that there will be some kind of upgrade pricing for when BFD4 launches based on BFD’s history, as well as every other major virtual drum instrument developer out there.
There is this comment from Drew about BFD Player having an upgrade path, but BFD4 isn’t specifically mentioned. I would assume that since Player is free, that the upgrade pricing wouldn’t be as favorable as having BFD3.