title: Is it possible to install freeswitch in Debian 9.4?
body: <p>I tried to install freeswitch in Debian 9.4 but i get some error. its say keys are invalid.</p>
  
  <p><code>root@.... :~# apt-get update 
  Hit:1 https://deb.nodesource.com/node_8.x jessie InRelease
  Hit:2 http://128.30.2.26/debian testing InRelease<br>
  Get:3 http://files.freeswitch.org/repo/deb/freeswitch-1.6 jessie InRelease [4,628 B]
  Ign:3 http://files.freeswitch.org/repo/deb/freeswitch-1.6 jessie InRelease
  Get:4 http://files.freeswitch.org/repo/deb/freeswitch-1.6 jessie/main amd64 Packages [65.5 kB]
  Fetched 70.1 kB in 2s (32.0 kB/s)<br>
  Reading package lists... Done
  W: GPG error: http://files.freeswitch.org/repo/deb/freeswitch-1.6 jessie InRelease: The following signatures were invalid: 20B06EE621AB150D40F6079FD76EDC7725E010CF
  W: The repository 'http://files.freeswitch.org/repo/deb/freeswitch-1.6 jessie InRelease' is not signed.
  N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
  N: See apt-secure(8) manpage for repository creation and user configuration details.
  </code></p>