The Windows 10 21H2 19044 is in the starting blocks and will soon be officially distributed to everyone. KB5003791 is now also available as a feature update directly from Microsoft.
Not much happens because everything that was planned was pushed into Windows 11. Windows 10 will be provided with non-security-relevant and security-relevant updates (at least) until 2025. The Release Preview channel will remain open for the pre-updates of Windows 10. This is then divided into two parts. Once for Windows 10 and once for Windows 11.
As it stands, Windows 10 21H2 19044 will remain the last version if you correctly interpret Brandon LeBlanc’s answer on Twitter. “We have not announced any future Windows 10 feature updates after 21H2.” So Windows 10 21H2 will likely be Windows 10’s last feature update. However, the OS will continue to be officially supported until 2025.
We haven't announced any future Windows 10 feature updates beyond 21H2.
— Brandon LeBlanc (@brandonleblanc) August 31, 2021
Conversely, this means: If any functions from Windows 11 should still be ported back, they will come via the non-security-relevant updates or the Windows Feature Experience Pack updates. Like for example, the last one is KB5004393.
Of course, we have to wait and see whether this will happen. But for Microsoft, it would make sense if the 21H2 were only supplied with updates without a new enablement package every six months. What good if there will be hardly any new functions if any.