Firefox version 52 will be the last complete update for Windows XP and Windows Vista. Security updates will be released, but no new features.
Firefox is one of the only browsers to offer any support for Windows XP and Vista. Microsoft itself ended support for Windows XP in 2014 and will end support for Windows Vista in 2017. Unsupported operating systems receive no security updates, have known exploits, and can be dangerous to use, which makes it difficult to maintain Firefox on those versions.
Firefox security updates for XP and Vista users will continue until September 2017, although new features will not be offered. In mid-2017, a final support end date will be announced based on the number of users still on Windows XP and Vista.
Unfortunately not. Most browsers (such as Google Chrome and Microsoft Internet Explorer) have already ended support for Windows XP and Windows Vista.
If upgrading your operating system is not an option, you can still expect continued Firefox security updates until September 2017.
In March 2017, if you are using Firefox with Windows XP or Windows Vista, you will automatically be updated to the Extended Support Release version of Firefox. You will continue to receive important Firefox security updates but no other features or updates. You do not need to do anything else.
If you want to keep your Firefox up to date, with all the latest features and updates, you'll need to upgrade your computer's operating system.
For planning purposes, enterprises using Firefox should consider September 2017 as the support end date for Windows XP and Vista.
Support for Windows XP and Vista has already ended for Firefox Nightly and Aurora users. Please consider moving to the release version of Firefox by downloading it here or upgrade your operating system to a version of Windows that Microsoft still supports, such as Windows 7, 8 or 10. Learn how here.