A spot from Windows Latest reveals that, while Windows 11 23H2 is still being fully supported until November 2025, thousands of users have reported the issue. The warning reads, “Get the newer version of windows to stay up to date.”.
Microsoft has acknowledged it as a known bug and confirmed the alert is an incorrect message caused by the update:
Microsoft support representative confirmed to Windows Latest that today’s end of support Windows update notification is a bug.
― Windows Latest, article