I am guessing you have 15.0.0.239 as that was not the last Flash 15 version as 15.0.0.242 and older is blocked and vulnerable. The 15.0.0.246 is not affected though according to Adobe.

The plugin check page needs to be manually updated as the version it currently says is current may not be, say for Flash. Check Flash version at http://www.adobe.com/software/flash/about/

For Firefox on Windows the current Flash player versions are 16.0.0.235 and the extended support version 13.0.0.259 at https://www.adobe.com/products/flashplayer/distribution3.html

https://helpx.adobe.com/security/products/flash-player/apsb14-27.html

Flash Player Plugin 10.3.183.66 to 15.0.0.242 (click-to-play) has been blocked for your protection. https://addons.mozilla.org/firefox/blocked/p794

fixed .. manuel removed old version

Old version of what?

Note that it is not Firefox 34.0.5 itself that is blocking (been released since December 1st) but due to the older Flash versions added to blocklist as of December 11. https://addons.mozilla.org/firefox/blocked/p794

Seems I'm having a similar problem-of sorts, I have the following plugins showing for FP: 16.0.0.235 and 15.0.0.246. The Windows control panel only shows FP16 as the installed version so the question is how come I have both version and how do I get rid of FP15?

Adobe Flash updates don't clean-up after themselves all the time.

First, grab the Adobe uninstaller from here: http://helpx.adobe.com/flash-player/kb/uninstall-flash-player-windows.html

Then grab the latest version of Flash from here: https://www.adobe.com/products/flashplayer/distribution3.html

Run the uninstaller, then reboot your operating system. Then you can run the Flash installer, with Firefox closed, of course. Note, if you still use IE, you'll need to reinstall the ActiveX version of Flash for IE. That uninstaller removes all versions of Flash that might be installed,