Previous versions of GnuTLS supported limited OpenPGP key authentication. That functionality has been deprecated and although is still made available, it is no longer recommended to use. The reason is that, supporting alternative authentication methods, when X.509 and PKIX were new and not well established, seemed like a good idea, in today’s internet X.509 is unquestionably the main container for certificates. As such supporting more options with no clear use-cases, is a distraction that consumes considerable resources for improving and testing. For that we have decided to mark this functionality as deprecated, and will be dropped in one of the next GnuTLS major releases.