Microsoft is now rolling two previews in the Dev Channel of the Windows Insider Program, including Windows 10 build 21277 and 20277. The build 20277 is part of the FE_RELEASE branch, and it is available as an automatic update with a couple of the fixes and no new features. Then there is build 21277, which is part of the RS_PRERELAESE branch, and it is available as an optional install that you must select manually through the Windows Update settings. Also, Windows 10 build 21277 is a minor update, but it ships with some new features and improvements.
According to the company, this is a temporary situation until everyone is switched to the RS_PRERELEASE branch after the holidays. Also, if you choose to install build 21277, you will no longer be able to switch FE_RELEASE branch. Unless you roll back to the previous version using the recovery settings during first ten days since the last installation.
Windows 10 build 21277
As for the changes with this confusing rollout, Windows 10 build 21277 introduces a new x64 emulator that allows ARM-based devices to install and run x64 applications from the Microsoft Store or external sources.
In addition, this flight ships with a preview for support of Emoji 12.1 and 13.0, which brings over 200 new glyphs, gender-neutral emoji designs, and tweaks to existing emojis.
Build 21277 also introduces a new smoother animation for opening and closing windows. You can now use the screen snipping experience (Windows key + Shift + S) to create a snip of your screen and paste it directly into a folder in File Explorer to save the screenshot there. Split keyboard mode support is now available for the touch keyboard in portrait mode, and the Snipping Tool can now be uninstalled using Settings.
Furthermore, the Registry Editor now supports CTRL + Backspace to delete words at a time, Offline Maps settings are clearer to understand, and the Start menu will now list the application icon instead of the folder when the folder only has one item.
The company also revealed that Windows 10 build 21277 re-enables many of the features that were previously temporarily removed, including emoji picker, redesigned keyboard, theme-aware splash screens, voice typing, and many others. However, these features will still limited for a select number of testers.
Microsoft is listing the complete set of improvements, fixes, and known issues for Windows 10 Insider Preview build 21277 at the Windows Blog.
Windows 10 build 20277
If you are staying in the FE_PRERELEASE, then Windows 10 build 20277 only receives a couple of fixes, including a fix that could result in the WinRE volume label being lost after multiple upgrades and apps not updating with error code 0x80073D02.
Microsoft is listing the complete set of improvements, fixes, and known issues for Windows 10 Insider Preview build 20277 at the Windows Blog.
Download Windows 10 build 21277 and 20277
The build 20277 preview is available immediately through the Dev Channel, and it will install automatically, but you can always force it from Settings > Update & security > Windows Update, and clicking the Check for updates button. If you want to install the build 21277, then you need to click the Download and install option from the Windows Update settings.
You can learn more about all the changes available in the current development process of Windows 10 in this guide.