The only configuration change required is to add the http2 parameter to existing listen directives. Please note HTTP/2 is only supported when the ssl parameter is also included
For those people that are already on http/2 I have a few questions.
Do you see googlebot using http/2 ? Is far as I know it's only 1.1
Google pagespeed is only reporting the speed from http 1.1? Or do you see the difference in webmaster tools?
The pagespeed probably goes up because you have to remove spdy to get http/2. Unless they use http/2.
I'm also interested in how much http/2 vs http/1.1 traffic you have. (bots excluded)