from maturity in the source code, extensive stress testing of the system, and automatic detection of many serious errors in drivers." InformationWeek summarized the release "our tests show the successor to NT 4.0 is everything we hoped it would be. Of course, it isn't perfect either." Wired News later described the results of the February launch as "lackluster." Novell criticized Microsoft's Active Directory, the new directory service architecture, as less scalable or reliable than its own Novell Directory Services (NDS) alternative. Windows 2000 is the last public release of Windows for PC-98, I486 and SGI Visual Workstation 320 and 540 as Windows XP runs solely on IA-32 only. Windows 2000 was initially planned to replace both Windows 98 and Windows NT 4.0. However, this would be changed later, as an updated version of Windows 98 called Windows 98 Second Edition was released in 1999. On or shortly before February 12, 2004, "portions of the Microsoft Windows 2000 and Windows NT 4.0 source code were illegally made available on the Internet." The source of the leak was later traced to Mainsoft, a Windows Interface Source Environment partner. Microsoft issued the following statement: "Microsoft source code is both copyrighted and protected as a trade secret. As such, it is illegal to post it, make it available to others, download it or use it." Despite the warnings, the archive containing the leaked code spread widely on the file-sharing networks. On February 16, 2004, an exploit "allegedly discovered by an individual studying the leaked source code" for certain versions of Microsoft Internet Explorer was reported. On April 15, 2015, GitHub took down a repository containing a copy of the Windows NT 4.0 source code that originated from the leak. Microsoft planned to release a 64-bit version of Windows 2000, which would run on 64-bit Intel Itanium microprocessors, in 2000. However, the first officially released 64-bit version of Windows was Windows XP 64-Bit Edition, released alongside the 32-bit editions of Windows XP on October 25, 2001, followed by the server versions Windows Datacenter Server Limited Edition and later Windows Advanced Server Limited Edition, which were based on the pre-release Windows Server 2003 (then known as Windows .NET Server) codebase. These editions were released in 2002, were shortly available through the OEM channel and then were superseded by the final versions of Server 2003. New and updated features Windows 2000 introduced many of the new features