(actuellement http1.1 dans les specifications hbbtv 2.0)
HTTP2's framing is a bit different, compression is different, and prioritization scheme is better suited for proxies.
The biggest difference is probably the prioritization scheme, which is much more flexible and good for proxies in HTTP2 as compared to SPDY
A very close second is the change to how header compression is done-- in HTTP2 it is much faster, much much more memory efficient, and compresses a bit less effectievly than SPDY's use of gzip.
The framing changes aren't worlds different, but they make the protocol more regular than SPDY was.
There are other differences, but these are the big ones in my opinion.
And, of course, HTTP2 is also much, much, MUCH better specified than was SPDY