Feature parity with graphql implementations

Hello I'm looking for comparisons in feature parity with the latest graphql specification.

Is gqlgen at par with the latest stable one? http://spec.graphql.org/ and what is the plan for feature releases when a new specification is out.

I'm mainly trying to find out if there is a parity difference between the JS implementations (as they seem to be the most used in production) in comparison to gqlgen.

Are all features covered? Is there anything missing? in comparison with the JS implementation or the latest available spec
If there is a new spec release, how fast would it be able to implement those changes.