Upgrading to HTTP/2 on Apache is incredible easy on a Debian testing:
First, let’s get Let’s Encrpyt, so we have HTTPS traffic.
$ apt-get install certbot python-certbot-apache
In the wizard enable all sites. Preferable force redirect to HTTPS.
Once that is installed, you can enable HTTP2.
Note: If you are using HTTP2 with Prefork you must use PHP-FPM or FastCGI, mod_php will not work.
If you are using threads or events everything will be fine. Apache 2 on Debian testing defaults to event.
Now enable the protocol in the site that was generated by certbot, e.g.:
Add the line “Protocols h2 http/1.1”.
systemctl restart apache2
DONE! Welcome HTTP.
p.s.: great video about the benefits and drawbacks of HTTP2: https://www.youtube.com/watch?v=0yzJAKknE_k