Let me quickly bring you up to speed on my issue.. I've been using GMS2 v2.1.5 from mid-2018 due to a bug that affected my project. Until recently it was fixed in v2.2.4 and I upgraded. All this while, I have been using an extension that allowed skeleton animations made from Spriter to work inside Gamemaker (extension made by Nux). But after the upgrade to v2.2.4, the extension broke. I contacted the author and he told me he won't be working on it anymore (at least for a long while). I rolled back to v2.1.5. Bought Spine (v3.8.75). Painstakingly rerigged + reanimated everything from Spriter into Spine. Exported the data and it does not work in Gamemaker.. @rIKmAN told me the stable version that worked in v2.1.5 was Spine v3.4.02.. (https://forum.yoyogames.com/index.php?threads/previous-spine-version-support.68834) Downgraded Spine to v3.4.02 but I can't open my Spine project anymore.. Please tell I don't have to rerig + reanimate everything again now in Spine v3.4.02, please... Any help?