'Compatible with service X' is a feature. If it stops being compatible with service X because service X changed their API, then you either need to fix it so it's compatible again, or refund to your customers.
If you want to announce you are compatible with service X as a feature, you should have an agreement of compatibility with service X.
If you want to announce you are compatible with service X as a feature, you should have an agreement of compatibility with service X.