When a state file is corrupt, unreadable, or from a newer build, rename it to <name>.json.bak (replacing any older backup) before loading empty, so the next save can't silently destroy it and the user can inspect or recover the contents.
When a state file is corrupt, unreadable, or from a newer build, rename it to <name>.json.bak (replacing any older backup) before loading empty, so the next save can't silently destroy it and the user can inspect or recover the contents.