Popular web browser Mozilla Firefox will be moved to an 'extended support release' aka ESR phase from March 2017on Microsoft Windows OS versions. These iterations are the popular Windows XP and Vista respectively.
However, there is nothing to panic as Firefox will continue working on the above OSes even in extended support phase till September 2017. This means that you will receive updates and security patches till September 2017, post which Firefox support would come to an end automatically.
At this point in time, it is worth noting that both Windows XP and Windows Vista are now legacy OSes and Microsoft no longer officially supports the former; support for the latter is also slated to end in 2017. Nonetheless, unofficial service packs for Windows XP still continue to do the rounds on the internet.
At this juncture, it is also worth noting that till September 2017, Mozilla will continue to automatically update your Firefox browsers on Windows XP and Windows Vista OSes; you need not take additional steps or make extra efforts to install new updates/patches to the browser. Do remember that Mozilla will not offer you any new features, despite seeding updates from March 2017.
Mozilla has stated that it would announce a final end of support date, for Firefox, on Windows XP and Windows Vista, during the middle of 2017. This end of support date could be September 30 2017 considering the fact that the user base for both Windows XP and Windows Vista are dwindling as of now.
However, Mozilla Firefox's status for Microsoft's Windows 7/8/8.1 remain unchanged.
