Windows NT 3.1 build 531

Windows NT 3.1 build 531 is the official Japanese RTM of Windows NT 3.1. The free build for Alpha and the checked build for x86 is available on a MSDN CD from April 1994. BetaArchive member ReflectiaX showed the 3.5inch 2HD floppy variation of this build’s Box for the NEC PC-9800 Series Computers. . A Compaq OEM CD containing the free build for x86 in both client and Advanced Server SKUs was uploaded to the Internet Archive on 14 December 2021.