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Tracking HTTP/2 Adoption: Stagnation


This article is about the adoption of HTTP/2.0 over the last four months and how it’s adoption has stagnated and the only change has been in early adopters updating the previous version of the protocol.

I often post about HTTP/2.0 on Twitter. 


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 modifications 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).

Adoption Growth

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.

Table of change

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 supported 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.

Table of change - Combined

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.

Supported Version White


Organizations Leading Change

Let’s turn our attention to the organizations supporting the change in HTTP/2.

Organisation Adoption

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).

Organisation Adoption Pie


In the last four months, the adoption of HTTP/2.0 has not improved. The data suggest that providers are upgrading their current support of HTTP/2.0 to the latest version but not adding support to older versions.

Related Articles

Get an overview of the changes coming in HTTP/2.0 and how these are implemented in Java EE 8. In this article, we talk about the specification and the support that will be available in Java 9 and JavaEE 8.

One of the most important developments in JavaEE 8 and Java 9 will be support for HTTP/2. Tomcat 9 supports HTTP/2 but it must be configured to use TLS. Head on over to Configure Tomcat 9 for HTTP/2 to find out how to add the appropriate configurations.

Why do we need HTTP/2.0: find out why we need it and what it’s going to give us.

Other Sources of Information

I often post about HTTP/2.0 on Twitter. 

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