Yeah, I mean most see the linear progression of the app and would rather expect things to continue to be compatible from a previous file standpoint. Perhaps even I missed a memo, but I wouldn't have expected my old builds to no longer work properly in the current iteration as that would imply the powers, enh, etc would no longer exist from a logic standpoint. Going in Reverse would be understandable in the same way that you can't take a USB-C plug and expect to put it into a DB port expecting to move data.
Related, side note...as rebuilding said builds would be annoying, can we view the old build files in a readable fashion, thus allowing manual recreation within the new versions? I don't "think" I'll have issues, but I'm not sure what version they were last saved in. That and I haven't tried manually reading the files in a while.