https://support.mozilla.org/en-US/kb/keep-flash-up-to-date-and-troubleshoot-problems The updates for the NPAPI Flash Player comes from Adobe either in its own update or by user downloading from Adobe and installing new version. Since you use Windows make sure you uncheck the extras on https://get.adobe.com/flashplayer/ before downloading. Neither Mozilla nor the Firefox web browser update Plugins. The NPAPI Flash Player Plugin is not installed in Firefox but on the system whether on Windows, Mac OSX, or Linux and Firefox scans and makes use of it. Type '''about:plugins''' in the Location (address) bar will show you where it is on your system. Google Chrome comes with its own Pepper Flash as this can be one of the reasons for frequent Chrome updates.