Keep old save files working after you add or rename things in an update

Players who spent forty hours building a base will not forgive a patch that wipes it. This entry shows how to let the AI change your game's data while old saves still open, and how to refuse a save that came from a newer version.

Why this works

A save is a promise made in an older shape of the game. Instead of teaching the game every old shape, you move a save one small step at a time up to the current one, so old and new saves travel the same road and you only ever test that road.

When not to use it

It is the wrong tool for data that is cheap to lose, such as a high score list or settings, where a reset is fine. It also cannot rescue a save from a newer build; for that, keep the player's older game available or export the world.

In the full entry

• What to build, step by step
• Starting values and the reason for each
• 4 common mistakes and the fix
• A diagram of every state
• 19 lines of example code with 5 checks that pass
• How your AI shows you that it works

Say this to your AI

Use the Spielerando entry "Keep old save files working after you add or rename things in an update" (read_entry old-save-files-after-update) in my game. Build it step by step, and show me how you checked that it works.

Or skip this and connect the MCP: your AI then finds all of this by itself.Connect the MCP