After an update, old saves load with missing items or crash the game

Every time you rename or reshape something your game stores, saves made before that day stop fitting. Here is a way to let every old save grow up step by step, and what to do with a save from a newer game than the one running.

Why this works

Old saves belong to real people, so every game version has to understand all earlier ones. Small upgrade steps that each handle one change, run in order, stay easy to check, and a step once shipped is never rewritten.

When not to use it

Skip it for a game with no lasting progress, such as short arcade rounds, or one that only lives on a server. Nothing old needs reading there; keep the data on the server and change it in one place.

In the full entry

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

Say this to your AI

Use the Spielerando entry "After an update, old saves load with missing items or crash the game" (read_entry save-version-migration-chain) 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