The ASA itself sees it at the TCP layer as tcp/80 and tcp/443 traffic (assuming continued use of default ports for unencrypted and encrypted traffic respectively). So no change or particular support is necessary there. Similarly the basic http operators (GET, POST etc. ) are unchanged so we can contiinue to look for those and detect, for instance, non-http operators embedded in an http request as, say, an attack targeting a web server.
I don't believe that protocol layer inspection, either in the base ASA of a FirePOWER module is aware of the http/2 binary framing layer (reference https://hpbn.co/http2/). So in that respect we cannot do any advanced inspection of http/2 traffic at this time (i.e. as of February 2017 with ASA 9.7 and/or FirePOWER 6.2 releases).
