init python:
    for slot in renpy.list_slots():
        renpy_version = renpy.slot_json(slot)['_renpy_version']
        if (renpy_version[0] == 7 and renpy_version[1] < 5):
            for save_location in renpy.loadsave.location.active_locations():
                fn = save_location.filename(slot)
                try:
                    renpy.savetoken.upgrade_savefile(fn)
                except:
                    renpy.display.log.write("Error upgrading save file:")
                    renpy.display.log.exception()