There's a line in one of the Ren'Py files you have to edit to use edited saves on newer versions of the engine, but instead of doing that I'd recommend just using the universal Ren'Py mod. It lets you alter variables, jump to scenes, etc.
So I get an error during the heist event/mission after using "steal on Rem" and her attacking me back. I really want this heirloom XD, and I've tried rollback and ignoring the exception. Need me to send the .txt?
Just realised there's option to attach it...