The final version of windows (only server, other variants of Windows never supported Itanium to begin with) was Windows Server 2008 R2. Based on Windows NT 6.1 (Win 7). This does not include updates released for Ser 2008 R2 sent out after 2018. Where they dropped Itanium CPUs and any x86_64 CPU that does not support PAE, SSE2 and NX extensions (The needed requirements for Win 8). Source Date: October 21st 2024