Windows 2000 build 1597

Windows 2000 build 1597.1 is an unleaked build of Windows 2000, which is mentioned in the file  from later builds.

netupgrd.inf

 * -- NETUPGRD.INX --
 * Upgrade support INF for upgrading from buildnumber > 1597
 * Copyright (c) 1993-1997, Microsoft Corporation
 * Copyright (c) 1993-1997, Microsoft Corporation
 * Copyright (c) 1993-1997, Microsoft Corporation