I have a struct Settings. I encode it to JSON with JSONEncoder().encode and save to UserDefaults. To load it, I decode it with JSONDecoder().decode from UserDefaults

Problem: my app is live, and I need to push an update which will introduce new variables to the Settings struct. After the update, decoding the already saved Settings struct will fail because the struct is now different.

Question: how do I decode the old saved Settings struct into the new updated struct? How I see it: I need to decode each key one by one, if it exists in the new Settings struct – assign it; if it does not – assign new value.

But I have no idea how.