HTTP2
HTTP/2 (originally named HTTP/2.0) is a major revision of the HTTP network protocol used by the World Wide Web. It was derived from the earlier experimental SPDY protocol, originally developed by Google. HTTP/2 was developed by the Hypertext Transfer Protocol working group httpbis (where bis means "second") of the Internet Engineering Task Force. HTTP/2 is the first new version of HTTP since HTTP 1.1, which was standardized in RFC 2068 in 1997. The Working Group presented HTTP/2 to IESG for consideration as a Proposed Standard in December 2014, and IESG approved it to publish as Proposed Standard on February 17, 2015. The HTTP/2 specification was published as RFC 7540 in May 2015.
The standardization effort was supported by Chrome, Opera, Firefox, Internet Explorer 11, Safari, Amazon Silk, and Edge browsers. Most major browsers had added HTTP/2 support by the end of 2015.
According to W3Techs, as of May 2019, 37.0% of the top 10 million websites supported HTTP/2.
HTTP/3 is the proposed successor (Internet Draft) to HTTP/2, that builds on it.