Some early leaked builds of Windows 11 had different internal identifiers, but the standard naming convention follows the YYHx format (e.g., 21H2, 22H2).
The Windows 11 version 21H2 update history on Microsoft Support catalogs every build from the initial launch through its end of service. Search results for Windows 11 (2105)
Are you trying to that shows "2105," or
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