Developers should keep the following in mind regarding HTTP2:
- Communications that are not using HTTP2 will still benefit from bundling.
- Some browsers, notably Chrome and Firefox, may only support HTTP2 when the connection uses TLS/SSL.
- Proxies in between the client and the server that don’t support HTTP2 may also affect the improvements HTTP2 would otherwise provide.
For a little more about the spec, I recommend this concise post from Akamai: https://http2.akamai.com/. And don’t overlook their awesome demo example of the improvements HTTP2 can provide: https://http2.akamai.com/demo.