How to understand why HTTP/2 is not enabled?

Question

Nginx

Debian 7.
Updated nginx from 1.6 to 1.10, added the treasured characters to the listenhttp2 directive , restarted nginx. But the site continues to be given over HTTP/1.1. There is a certificate, configured a long time ago, everything is green in the Security panel in DevTools, no errors. The browser supports HTTP/2, of course. The nginx config passes the check, there are no errors on reboot. There is only one warning in the logs:

2016/06/27 15:49:33 [warn] 24676#24676: duplicate MIME type "text/html" in /etc/nginx/nginx.conf:37

There is a --with-http_v2_modulenginx -V flag in the output . There are two nuances:

1. Nginx acts as a frontend and proxies requests to apache.
   
2. The listen directive specifies not only the port, but also ip: listen 1.2.3.4:443 ssl http2 default_server;.
   

Куда смотреть, что крутить?

Answer 1

https://www.nginx.com/blog/supporting-http2-google...
Нужет OpenSSL 1.0.2g или выше