Microsoft Windows XP 64-bit Edition was a version of Microsoft's Windows XP operating system designed to run on Intel Itanium family of processors, in their native 64-bit mode. It should not be confused with Windows XP Professional x64 Edition, which is designed for x86 processors supporting the x64 extensions. Two major versions of Windows 64-bit Edition were released: Security updates were discontinued for Windows XP 64-bit Edition in lieu of Windows XP Professional x64 Edition.