> Input objects do not implement interfaces http://lacinia.readthedocs.io/en/latest/input-objects.html Is this statement still true?

Yes. That's in the GraphQL specification, input objects are simple data values. Essentially, they are a way to package up a bunch of data as a single field argument.

FYI: The PRs are still pending. We're caught in the middle of a transition in how we deploy our services internally, but I want to keep to the promise that we don't do a final release until we run the PRs in production.