Announcing Windows 10 Insider Preview Build 21277

Today we are releasing Windows 10 Insider Preview Build 21277 (RS_PRERELEASE) to Windows Insiders in the Dev Channel.

As mentioned here, we are giving Windows Insiders in the Dev Channel the option to receive builds from the RS_PRERELEASE branch. These builds will be offered as an optional update through the “seeker” experience in Windows Update. This means Insiders will have to go and choose to install the currently offered RS_PRERELEASE build. Once they do, they will continue to receive RS_PRERELEASE builds going forward. This optional experience for receiving RS_PRERELEASE builds is just temporary – we plan to move all Insiders in the Dev Channel back to receiving builds from RS_PRERELEASE sometime after the holidays. As a reminder, Dev Channel builds are not matched to a specific Windows 10 release.

Also: features like the updated emoji picker, redesigned touch keyboard, voice typing, theme-aware splash screens, and others that were removed temporarily at the end of October will be returning for Insiders who install this RS_PRERELEASE build. However, please note some of these features will continue to be available only to a subset of Insiders and will get enabled for more Insiders over time.

Be sure to check the list of known issues below. The list of fixes and known issues between FE_RELEASE builds and RS_PRERELEASE builds will NOT be the same.

IMPORTANT NOTE: Once an Insider chooses to install a RS_PRERELEASE build, they cannot move back to receiving FE_RELEASE builds as their device will be on a higher build number. Insiders will still have the option to roll back to a previous version for up to 10 days or until you take another build.

What’s new in Build 21277

Important Insider Links

You can check out our Windows Insider Program documentation here, including a list of all the new features and updates released in builds so far. Are you not seeing any of the features list for this build? Check your Windows Insider Settings to make sure you’re in the Dev Channel. Submit feedback here to let us know if things weren’t working the way you expected.

If you want a complete look at what build is in which Insider ring, head over to Flight Hub. Please note, there will be a slight delay between when a build is flighted and when Flight Hub is updated.

Before you update your machine, visit the Windows Insider Blog today to view full details on new features, general changes, improvements, known issues and much more!