Unlike a server, you can't just redeploy.
Strategy: ship model assets via the app bundle or a signed download, version them, and re-embed the corpus when the embedding model version changes (the index is only valid for one embedding model).
For data, re-index on content-hash change. Use OTA config to flip features.
Plan for the case where the user is on an old model version — keep the index's model version recorded so you know when a re-embed is required.