itch.io

I have a game that does saves similarly. There's a save folder in your old version. Look in it, all those SLF files are your save files. Transfer those over to the new version's save folder. While it likely doesn't apply in this case, big updates can break saves with games in progress. Still, I recommend loading from a save that is between chapters. Also, it's a good idea to keep a hold of the old version until you are sure the new version is stable.