In a rare Monday release, Microsoft flighted Windows 10 Insider Preview build 20279 to the Dev channel. According to the blog post, there's nothing new in this build; the team just wanted to "test our ability to quickly follow-up a flight with another flight."

That's right; the official reason for this build's existence is because Microsoft just wanted to make sure that it can still ship Windows 10 Insider Preview builds, like it does at least once a week. But of course, this is from the fe_release development branch, which is filled with both mystery and misinformation.

Let's talk about what fe_release is, and what it isn't. It is certainly not a preview of the next version of Windows 10, or frankly, anything that will ship to non-Insiders. Windows 10 21H1 will be a minor update, just like 20H2 was, and just like we saw when 20H2 was in testing, Microsoft is going through a fake release phase before something completely unrelated to it heads to the Beta channel.

What's really happening is that internally, Microsoft is testing Windows 10X, which should be released with 21H1. In fact, this should be the RTM build, according to pretty much all reports. The company was originally planning to release Windows 10X alongside 20H2, but it got delayed, and that's why we're getting two minor updates in a row.

In short, this is a build that's just being sent to Insiders for the sake of it, just like everything else from the fe_release branch. There are no fixes listed, but there are some known issues:

  • We’re looking into reports of the update process hanging for extended periods of time when attempting to install a new build.
  • Live previews for pinned sites aren’t enabled for all Insiders yet, so you may see a grey window when hovering over the thumbnail in the taskbar. We’re continuing to work on polishing this experience.
  • We’re working on enabling the new taskbar experience for existing pinned sites. In the meantime, you can unpin the site from the taskbar, remove it from the edge://apps page, and then re-pin the site.
  • We’re working on a fix for an issue resulting in some users seeing error 0x80070426 when using their Microsoft account to sign into various apps. If you encounter it, rebooting your PC may resolve this.
  • We’re working on a fix for an issue where, in recent Dev Channel builds, no drives appear under Settings > System > Storage > Manage Disks and Volumes. As a workaround, you can manage your disks in the classic Disk Management tool.

Insiders do still have the option of returning to the rs_prerelease branch, which is what they actually signed up for in the Dev channel. In fact, when Microsoft released build 21277 to the Dev channel, the team made a point of warning users that there's no turning back if you opt into it, an empty statement when it's looking more and more like starting next week, everyone on the Dev channel will be on rs_prerelease.

And of course, Microsoft hasn't said a word about any of this. There's still no official confirmation about why fe_release exists at all, when Windows 10X is coming, or even what the next Windows 10 feature update will be. There isn't even anything being tested in the Beta channel. All that we get is statements like, "This build is largely the same as Build 20277, but we wanted to test our ability to quickly follow-up a flight with another flight."