[German]Microsoft has released not one but two Insider Preview builds, the 20277 and the 21277, of Windows 10 in the Dev Channel for testing on December 10, 2020. Here's some information.
Things are a bit tricky, as Microsoft explains on the Windows Blog in the announcements for Preview Build 20277 and Build Build 21277. Windows 10 Insider Preview build 20277 is from the FE_RELEASE branch.
The Insider Preview build 20277, on the other hand, is from the RS_PRERELEASE branch. Microsoft wants to give Windows Insiders in the Dev Channel the opportunity to receive builds from the RS_PRERELEASE branch. These builds will be offered as an optional update via the search button in Windows Update.
This means that Insiders will have to select the currently offered RS_PRERELEASE build to install it. Insiders can choose to install build 21277. Once they do, they will continue to receive RS_PRERELEASE builds in the future.
Insiders who choose to install FE_RELEASE build 20277 will continue to automatically receive FE_RELEASE builds until Microsoft moves all Insiders in the Dev Channel to RS_PRERELEASE builds sometime after the holidays. Microsoft is still looking for Insiders to use FE_RELEASE builds and provide feedback on those builds. A bit complicated, regarding the details read the linked blog posts.
