Firefox users who are on Windows XP now have until August 28, 2018 to upgrade their machines. In the grand Internet tradition I will explore this by pretending someone is asking me questions.

Why?

The last Firefox release supporting Windows XP is Firefox ESR 52. Previously Firefox ESR 52 was set to end-of-life on or around May of 2018 after the next ESR, Firefox ESR 59, had been released and stabilized. Now, with an email to the Enterprise, Dev Platform, Firefox Dev, and Mobile Firefox Dev mailing lists, :Sylvestre has announced that the next ESR will be Firefox ESR 60, which extends the Firefox ESR 52 end-of-life to August 28, 2018.

No, not “Why did it change,” Why should anyone still care about Windows XP? Hasn’t it been out-of-service for a decade or something?

Not quite a decade, but the last release of Windows XP was over nine years ago, and even Microsoft’s extended support tapped out nearly four years ago.

But as to why we should care… well, Windows XP is still a large-ish portion of the Firefox user base. I don’t have public numbers in front of me, but you can see the effect the Windows XP Firefox population numbers had on the Firefox Hardware Report when we diverted them to ESR this past March. At that time they were nearly 8.5% of all Firefox users. That was more than all versions of Mac Firefox users.

Also, it’s possible that these users may be some of the most vulnerable of the Internet’s users. They deserve our thought.

Oh, okay, fine. If they matter so much, why aren’t we supporting them forever?

As you can see from the same Firefox Hardware Report, the number of Windows XP Firefox users was in steady decline. At some point our desire and capability to support this population of users can no longer match up with our desire to ship the best experience to the most users.

Given the slope of the decline in the weeks leading up to when we migrated Windows XP Firefox users to Firefox ESR, we ought to be getting pretty close to zero. We hate to remove support from any users, but there was a real cost to supporting Windows XP.

For instance, the time between the ESR branch being cut and the first Windows XP-breaking change was a mere six days. And it wasn’t on purpose, we were just fixing something somewhere in Gecko in a way that Windows XP didn’t like.

So who are we going to drop support for next?

I don’t know of any plans to drop support for any Operating Systems in the near future. I expect we’ll drop support for older compilers in our usual manner, but not OSs.

That pretty much sums it up.

If you have any questions about Firefox ESR 60, please check out the Firefox ESR FAQ.

:chutten