HTTP/2 is a new version of the popular protocol that is for communication between the web server and the browser. It is a lower level technology than Drupal, so taking HTTP/2 into use does not require any modifications to your application or installation of Drupal modules. Drupal 8 introduces the request-response model to Drupal developers, but on a higher level - this is not to be confused with HTTP/1.1 vs. HTTP/2.
HTTP/2 is an evolution, not a revolution. It makes traffic flow more efficiently, but offers no stark for the end user of the site. But when use in scale it makes for a more efficient internet and improves performance of Drupal 8 REST API based applications and Big Pipe based renderingby streaming traffic to a single open connection.
To enable Drupal to talk HTTP/2 then you'll need the following things:
- HTTP/2 compatible browser
- HTTP/2 compatible web server
- Encrypted SSL/TLS traffic between the two
Most browsers today are "evergreen" and update continuously. Popular browsers used by billions of people have supported HTTP/2 for months now. For web servers we're heading towards the new version being the standard, but in the meanwhile you'll need to select or update to a version that supports it. SSL traffic is not a hard requirement for HTTP/2, but in essence it's necessary to bypass firewall limitations. HTTP/1.1 firewalls expecting text traffic would probably interpret binary HTTP/2 traffic as malicious.
Learn more about how to get started with Drupal and HTTP/2 today: