Windows hot-patching supports x86-32, x86-64, 64-bit ARM, and Itanium, but why not the other architctures like 32-bit ARM, MIPS, Alpha AXP, PowerPC, and SH-3?

These architectures fall into two buckets.

MIPS, Alpha AXP, PowerPC, and SH-3 all predate hot-patching, so they naturally couldn’t conform to rules that didn’t exist yet.

Meanwhile, 32-bit ARM support was introduced¹ to Windows in the Windows 8 era, and at that time, hot-patching had already existed. But there were no provisions for hot-patching 32-bit ARM binaries because hot-patching is a Windows Server feature. Since there was no version of Windows Server for 32-bit ARM, there was no need to support hot-patching on 32-bit ARM binaries.

¹ More accurately, re-introduced, since Windows CE supported 32-bit ARM as well.

Raymond has been involved in the evolution of Windows for more than 30 years. In 2003, he began a Web site known as The Old New Thing which has grown in popularity far beyond his wildest imagination, a development which still gives him the heebie-jeebies. The Web site spawned a book, coincidentally also titled The Old New Thing (Addison Wesley 2007). He occasionally appears on the Windows Dev Docs Twitter account to tell stories which convey no useful information.