i don't see any easy way there. you would possibly have to disassemble your save and fix whatever points to something broken, so you would have to find out what's wrong in the older version, compare it with the new version, and manipulate your save accordingly, and then maybe have to convince the game engine that this save is not corrupted, because likely the game will do checks on the saves. i estimate that replaying will take less time and efforts.
that's more or less guessed, based on how games usually work. can't test run saves from other computers, my system is set that way; sandboxed saves and all that, modified/imported files can't run here.
besides, very busy with bughunting a nude mod for some ancient non lewd game.