The installer in the latest 24H2 Preview build now checks to determine if SSE4.2\SSE4.A is present. https://www.neowin.net/news/microsoft-adds-sse42-to-the-list-of-compatibility-blocks-in-windows-11/ You can still install it but you can't boot Windows if its missing. That keeps PCs made before 2010 from being eligible to run 24H2.
Processors prior to 2010 are eligible as long as they are: https://www.neowin.net/news/how-to-check-if-your-old-computer-can-run-windows-11-version-24h2/
to note: 23H2 gets updates until end of 2025. any cpu on LGA 1155/1156 should be able to perform POPCNT and SSE4.2.
