Windows 11 build 21996

Windows 11 build 21996 is the earliest available build of Windows 11. This build was shared on 15 June 2021. Some areas already identify itself as Windows 11, however the kernel version remains the same.

New System Requirements
Windows 11 now requires the following.
 * 4GB RAM
 * Secure Boot enabled
 * TPM2

General

 * Secondary monitors no longer display the taskbar.

Bugs and Quirks

 * On some machines, attempting to upgrade will cause a  bugcheck. Retrying the upgrade may let the user successfully upgrade.