HTTP/2 : why upgrading the web?

HTTP is the protocol who rules the WEB. 20 years old, the version 2, major upgrade is now cooked and nearly ready to be used by real peoples. So, how new the new HTTP version is? What is the new features added to the protocol? Is it great to used? Does it will be used or be the next ipv6 like giant internet migration? Overview of HTTP2 and why it's great.