After 15 years we have a HTTP protocol new major version.
It's a brave new world, with new rules. Transaction multiplexing and smaller headers means no more need to aggregates JS/CSS files to reduce HTTP requests.
Previous attempts to change dramatically HTTP, like QUIC and SPDY, partially failed.
Safari 9, the new version of the last major browser that lacks HTTP/2 support, will be released on September 30th.
I recently tested also Microsoft Edge against Akamai HTTP/2 demo and failed. Instead Internet Explorer 11 on Windows 10 works.
I don't know why Microsoft Edge HTTP/2 doen't work in my test and I don't know why Microsoft declares otherwise, but can I use says that HTTP/2 on Internet Explorer on Windows 10 and in Microsoft Edge works. Maybe Edge is still too buggy... it's early days man, but we are here.
The client side of this revolution is almost full set.
Akamai demo is HTTP/2 draft 14. Google in production now uses HTTP/2 draft 15. Others not so updated infos about various implementations are linked on the official site.
Most of my work is on LAMP platform. Sadly the server part is a bit late. Apache main target is HTTP 1.1, but we have mod_h2 that will be released with Apache 2.5 branch and backported to Apache 2.4.x in the near future.
HTTP 2 requires HTTPS encryption: you must go full HTTPS Everywhere. It sounds bold and a huge step for cheap sites: now is a big stop, but in 6 months or a year this can change. If cheap hostings start to sell HTTPS default domains with big HTTP2 banners in homepage... why not, I can dream!
I wonder if hosting providers have begun testing HTTP2.
For local development use self-signed certificate. It's not too easy and the security warnings are very annoying, but for now it's the only way AFAIK.