It is important to note that Version 21H2 reached its end of servicing on October 8, 2024. The Windows 11 Release Health page at Microsoft Learn explains that devices on this version should be updated to a newer version like 23H2 or 24H2 to continue receiving security updates. Common Confusions

If you are looking for information on early versions of Windows 11, the following articles provide the most relevant historical and technical context: Essential Articles for Early Windows 11

You may be thinking of Windows 10 version 21H1 (May 2021 Update), which was released just before Windows 11 was announced.

Some early leaked builds of Windows 11 had different internal identifiers, but the standard naming convention follows the YYHx format (e.g., 21H2, 22H2).

There is no official release of Windows 11 under the version name This number appears to be a combination or a slight mislabeling of two separate milestones in Windows 11's early history:

The Windows 11 version 21H2 update history on Microsoft Support catalogs every build from the initial launch through its end of service.

For a deep dive into the features that defined the first version (Build 22000), Hands-on with Windows 11 Build 22000.51 provides a visual tour of the redesigned Start menu, Taskbar, and Widgets introduced in mid-2021.