I have ubuntu 16.04, firefox version 47. and according to this page https://helpx.adobe.com/flash-player.html my flash player version is
21.0.0.197.
It was working fine till about a week ago when some updates were installed. Unfortunately i did not note what they were.
I have no video on firefox. The sound works fine, but in the flash box is just a black screen. I cant even view the settings panel.
I followed the directions here https://help.ubuntu.com/lts/ubuntu-help/net-install-flash.html , did a purge first, then installed. Same issue. So I tried the install that I found on a few pages.
sudo add-apt-repository ppa:nilarimogard/webupd8
No good there also. Note: Chrome works fine, its just not working in firefox.