HTTP2

HTTP2 is the new, better, faster HTTP and it replaces Googles SPDY (http://programming-2.blogspot.de/search?q=SPDY). One really informative site to HTTP2 is https://http2-explained.readthedocs.org/en/latest/index.html

To use HTTP2, you need an client. CURL support it, but not as default. To use HTTP2 with CURL on MacOSX, you have to install CURL with brew:

brew install curl --with-nghttp2

Now you can check out HTTP2 with CURL

If you got following error:
curl: (1) Unsupported protocol
You use an CURL without compiled HTTP2 support. On MacOSX brew doesn't replace the existing CURL. You have to use the full path to the CURL from brew:

/usr/local/opt/curl/bin/curl --http2 -I -v https://google.com