We've decided to move Windows XP to the Firefox 52 ESR branch, so that Firefox 51 will be the last mainline version to support the platform. We still don't have an official EOL date for XP support, but moving the platform to the ESR branch means that we will *not* need to worry about new feature support for XP which is becoming increasingly difficult.

Note that the above plan is tentative until fully approved by our leadership team.

(In reply to Peter Dolanjski [:pdol] from comment #1) > Note that the above plan is tentative until fully approved by our leadership > team. This was approved so we'll be moving forward.

(In reply to Peter Dolanjski [:pdol] from comment #1) > Summary: Move Windows XP to Firefox ESR 52 → Move Windows XP and Vista to Firefox ESR 52 Hello I have been Nightly-testing on my OS, Windows Vista SP2 32bit, for many years - in fact, writing this on today's Nightly 52.0a1 20161013030204. I had bookmarked this bug when it was "XP" only and today, when revisited, I was frustrated to find out it had been modified to also include Vista :-( I am very well aware that Microsoft's Extended support for Vista ends in April 2017; I am also very grateful the Mozilla Team had not go down (yet) the Chromium route, i.e. abandoning Vista since last April... The XP people have been supported in Release Firefox for more than two years already since XP became EOL'd, why are the Vista owners being treated differently? The Vista codebase is very close to Windows 7, so not such a heavy maintenance burden; and according to https://people.mozilla.org/~danderson/moz-gfx-telemetry/www/#view=general Windows Vista SP2 accounts to 1.0% of overall Windows users, i.e. 1.0%*97.3%=0.973% of all Firefox users, which is almost double the amount of current Linux users... Fx ESR 52.0 will be released on March 7th, 2017, along with Fx Release 52.0. According to this bug, the next stable Release Fx 53.0 (April 18th, 2017) won't even run on my current OS; if I get this straight, does this also mean I won't be able to test the next Nightly 53.0a1 cycle (due Nov 7th 2016), too? Firefox was the only viable solution for Vista users, since all Chromium-based (Blink Engine) browsers won't even run nowadays in their recent versions; Internet Explorer 9 is practically unusable on most recent sites; Legacy Opera 36 and Firefox ESR 52.x (until the start of 2018) will be all left; your decision will also deprecate the Vista-based Windows Server 2008 SP2 OS, which will remain under MS Extended Support until 2020! Reading Mozilla created Bugzilla bugs over the years, I very well know that it's futile to even argue Mozilla devs' decisions, comments such as this one are considered as pollution... Please do not treat this comment as a rant, it most certainly isn't! Treat it as food for some more thought on deprecating Vista, an OS surely undeserving of the horrible death Microsoft themselves and most software vendors are planning for it... Living in financially tormented Greece, being currently unemployed, I have no immediate plans (or means) to replace this old but still perfectly functioning laptop, which, for the most part, meets my computing needs... Kind regards

(In reply to Vangelis from comment #3) > The XP people have been supported in Release Firefox for more than two years > already since XP became EOL'd, why are the Vista owners being treated > differently? > Windows Vista SP2 accounts to 1.0% of overall Windows users, i.e. > 1.0%*97.3%=0.973% of all Firefox users, which is almost double the amount of > current Linux users... FWIW, these arguments aren't new and I've responded to them in bug 1130266. > Fx ESR 52.0 will be released on March 7th, 2017, along with Fx Release 52.0. > According to this bug, the next stable Release Fx 53.0 (April 18th, 2017) > won't even run on my current OS; if I get this straight, > does this also mean I won't be able to test the next Nightly 53.0a1 cycle > (due Nov 7th 2016), too? Nightly probably won't stop running on Vista immediately on November 7th but it might happen shortly after. > Living in financially tormented Greece, being currently unemployed, I have > no immediate plans (or means) to replace this old but still perfectly > functioning laptop, which, for the most part, meets my computing needs... Other than sticking with ESR 52, you might want to consider installing Linux. Just a suggestion. There might of course be reasons why Linux isn't a viable option for you.

Let's dupe it, because bug 1303827 has implementation details.