With a couple of Lumia 950 XL pre-order rounds already organized (and closed) in several worldwide markets, and the smaller 950 variant reportedly shipping early to lucky AT&T buyers, Windows fans were left wondering exactly what version of the mobile OS they’d be getting.
As it turns out, it’s probably a newer build than last month’s 10581, carrying the digit combination 10586, and currently dispatched to Insiders in the Fast Ring. Microsoft hasn’t confirmed this yet, but extremely credible sources tell us Windows 10 Mobile officially enters the RTM (Release to Manufacturing) phase of its lengthy development now, requiring an extra week or two of formal sanctioning before moving to general availability.
Bottom line, there’s no need to worry Lumia 950 or 950 XL units might be delivered with glitchy software pre-installed, or essential features missing, especially since Win 10 has been stable enough for over 5 percent of Microsoft-endorsed phones to run it as early as October.
Similarly, if Acer or some other hardware manufacturer decides to launch a Windows 10-powered handheld tomorrow, build 10586 is what will keep everything nice and smooth. Compared to iteration 10581, beta testers should notice universal fixes for a host of minor bugs, including app crashes during SD card migration, various Start experience corruptions, and Store download reliability issues.
Unfortunately, if you happened to perform a factory reset before installing build 10581, upgrading to 10586 may send your phone into an endless reboot loop. Tread carefully therefore, back up all your data in advance, and follow Microsoft’s simple instructions for getting out of the pickle.