Decided to try out posting weeknotes about software engineering https://quanttype.net/posts/2024-08-18-weeknote-1-schema-evolution.html

@Miikka Huh, I’ve always this backwards compatibility as well:

Forwards compatibility is required so that the old app versions accept responses from the backend service.

@alpha Yeah, that's fair. That's a sensible way to talk about changes to the hypothetical backend service here, but for schemas I think it makes sense to make the distinction.

If you were able to upgrade everything (in this scenario, apps and backend) at once but you still had old data laying around, you'd care about backwards compatibility but you could ignore forwards compatibility.