[lewisl9029]

The versioning problem can usually be resolved fairly elegantly by versioning on a field-by-field level, i.e. adding a new field called x-v2 and serve it alongside x without removing the original. You can add some kind of a deprecation warning to x to dissuade new clients from using it.

With this approach you can end up with a somewhat noisy schema, but for public APIs it's usually worthwhile to just keep the old versions forever to avoid breakage. For private APIs, with good tracking, you can find out when the original field stops getting requested, and clean up your schema then with relatively little risk.