If it doesn't import correctly, that is a bug with GameMaker. It is not my responsibility to clean up after YoYoGames' messes. I would report this bug to the correct people (YoYoGames and not me) on GitHub - New Issue · YoYoGames/GameMaker-Bugs (github.com) If they refuse to be responsible and fix what they broke, let me know and I'll see what I can do, if anything. However, if their asset importer is completely broken and they don't fix it, there is nothing I can do. (I could technically try to recreate the projects and yymps files from scratch in the IDE version you mentioned, and see if that fixes it, but that will break the extensions from being able to work in older versions, which I'd like to avoid doing). TL;DR if YoYoGames fixes this on their end, it should work in both older and future versions of GameMaker.