This article is about the adoption of HTTP/2.0 over the last four months. Specifically, it's about how it’s adoption has stagnated and the only change has been in early adopters updating previous versions of the protocol.
HTTP/2.0 is the next version of the HTTP protocol and will deliver many benefits over HTTP 1.x. If you want a quick overview of the new HTTP/2 protocol you might want to read my article HTTP/2 in a Nutshell, for the full story you should read the technical specifications.
Tracking HTTP/2.0 Adoption
Servers can advise that they support HTTP/2 during the SSL handshake and, with a modification made to Shodan by John Matherly that track the negotiated HTTP versions searches of the data collected, can be made using the ssl.alpn filter.
John wrote a blog post researching the state of HTTP/2.0 adoption in December 2015 and this article is an update to that story. I will rerun the reports that John produced and compare the results.
Analysis of Adoption
Let's see where we have come in the last five months by starting with the most popular HTTP versions on the Internet for HTTPS servers (port 443).
If we analyze the two graphs (December full report, April full report) by looking at the percentage of all reported server support for each protocol type, we can see that the adoption of HTTP/2 has increased 100% to 10% of all surveyed servers.
However, further analysis shows that growth has come from providers upgrading the incumbent version of HTTP/2 to the latest specification. It can be implied that providers have upgraded from draft versions 14 and 17 and from HTTP/2 (cleartext). The clear text version is not by Firefox or Chrome.
Looking deeper into data by combining all HTTP 1.x versions into one group, all HTTP 2 into another group, and all SPDY versions in a different group, we can see that there is no significant change in protocols supported.
As expected HTTP 1.x dominates the list of support protocols, with SPDY in second place and HTTP/2 trailing last. There is still a lot of work to be done.
Organizations Leading Change
Let's turn our attention to the organizations supporting the change in HTTP/2.
Google is a new entrant and leads the change to HTTP/2. SingleHop, CloudFlare, and SiteGround still continue at the top while Amazon and OVH SAS come up behind (December full report, April full report).
In the last four months, the adoption of HTTP/2.0 has not improved. The data suggests that providers are upgrading their current support of HTTP/2.0 to the latest version but not adding support to older versions.