The forum polled your active plugins and discovered two versions of the Flash plugin:

• Shockwave Flash 19.0 r0
• Shockwave Flash 17.0 r0

Try removing the old version. The official way is to use Adobe's uninstaller, and then reinstall:

• https://helpx.adobe.com/flash-player/kb/uninstall-flash-player-windows.html
• https://www.adobe.com/products/flashplayer/distribution3.html

As a shortcut, it's usually safe to simply delete the one unwanted DLL file from disk. It's almost certainly in the following folder --

C:\Windows\SysWOW64\Macromed\Flash

-- but to confirm, you can type or paste about:plugins in the address bar and press Enter to load it. Use Find (Ctrl+f) to check for npswf32 in the page. When you find the older version, it will show the exact path and file name of the DLL you want to remove.

Please don't remove other files from that folder, since they may be used by Internet Explorer.

Adobe had a new update Nov 10 and last one was on Oct 16.

You appear to have two versions of Flash Player installed on system as said. This can cause Firefox to try and make use of older version and would explain the need to update message.