title: Apache/2.4.18 (Ubuntu) mod_proxy_wstunnel
body: <p>I'm trying to use the Websocket Proxy in Apache, but keeps reporting non existent module.
  $ sudo a2enmod mod_proxy_wstunnel
  ERROR: Module mod_proxy_wstunnel does not exist!</p>
  
  <p>This should be available from 2.4.5!
  <a href="https://httpd.apache.org/docs/2.4/mod/mod_proxy_wstunnel.html" rel="noreferrer">https://httpd.apache.org/docs/2.4/mod/mod_proxy_wstunnel.html</a></p>
  
  <p>Is this an Ubuntu version problem?
  How can I install this?</p>