Windows 11 build 21327

Windows 10 build 21327 (fs_prerelease) is a build of Cobalt, the 21H2 development semester of Windows as a service. A issue related to this build was posted to Visual Studio's Developer Community by a Microsoft employee on 11 March 2021.

The build tag is extremely similar to 10.0.21327.1000.rs_prerelease.210226-1427, differing only in 2 characters, both adjacent keys on a standard QWERTY keyboard (3 is to the right of 2, and F is directly below R), suggesting that the original post might have been a typo. As such, the existence of this build cannot be confirmed. The only other appearance of the "fs_" prefix so far has been in Windows 11 build 21380, also of questionable authenticity.