Windows 11 build 25121

Windows 11 build 25121 is a build of Copper, the 23H1 development semester of Windows as a service. The build number was mentioned in an issue posted on the GitHub repository of Visual Studio Code on 18 May 2022. Two images showing Windows Terminal running in this build were later shown in comments under a pull request posted on the GitHub repository of Windows Terminal on 26 May 2022.

Components from the ARM64 version of this build were discovered on the Microsoft Symbol Server on 17 May 2022.