Microsoft Windows version history

Did You Know?

• Windows 1.0 was briefly codenamed 'Interface Manager' before the windowing system was implemented.
• Windows 1.0 included a game called Reversi.
• Windows 3.0 could run in real, standard, or 386 enhanced modes and was compatible with any Intel processor from the 8086/8088 up to the 80286 and 80386.

OS/2 and Windows 2.x

During the mid to late 1980s, Microsoft and IBM cooperatively developed OS/2 as a successor to DOS, which would use the protected mode of the Intel 80286 processor and up to 16 MB of memory. OS/2 1.0, released in 1987, supported swapping and multitasking and could run MS-DOS executables. IBM licensed Windows' GUI for OS/2 as Presentation Manager, and the two companies stated that it and Windows 2.0 would be almost identical. By 1987, Computerworld reported that Bill Gates had pushed Windows almost fanatically for years, telling skeptical DOS software companies that developing for Windows was vital for compatibility with future DOS versions. In a 1987 interview, Gates said Microsoft would release Windows applications first with cheap upgrades to OS/2 versions, while others said they would release for OS/2 first. Presentation Manager was not available until OS/2 1.1 in 1988, and its API was incompatible with Windows. OS/2 1.2 in 1989 introduced the HPFS file system. By the early 1990s, conflicts developed; Microsoft wanted to further Windows, while IBM desired future work based on OS/2. They agreed IBM would develop OS/2 2.0 and Microsoft would develop OS/2 3.0, but the agreement fell apart. IBM continued OS/2, while Microsoft renamed its unreleased OS/2 3.0 to Windows NT, written anew mostly independently.

Windows NT 3.x

Microsoft continued developing Windows NT for business users, with Dave Cutler as the main architect. Cutler, one of the chief architects of VAX/VMS at Digital Equipment Corporation, was hired in October 1988 to create a successor to OS/2 but instead created a completely new system. He had been developing a follow-on to VMS called MICA, and when DEC dropped the project he brought the expertise and around 20 engineers to Microsoft. Windows NT Workstation arrived in beta form at the July 1992 Professional Developers Conference in San Francisco. Microsoft announced intentions to develop a successor to both Windows NT and Windows 3.1's replacement (Windows 95, codenamed Chicago) that would unify the two into one operating system, codenamed Cairo. Cairo proved more difficult than anticipated, and NT and Chicago were not unified until Windows XP, though Windows 2000 had already unified most system components. Parts of Cairo, notably the WinFS file system, had still not made it into Windows as of 2025. Driver support was lacking due to the increased programming difficulty of NT's hardware abstraction model, a problem that plagued the NT line through Windows 2000. Programmers found writing drivers for NT too hard, and hardware developers were reluctant to develop drivers for a small market segment. NT was also resource-intensive on limited hardware, making it suitable only for larger, more expensive machines.

Windows XP and Windows Server 2003

Windows XP, codenamed Whistler, was released on October 25, 2001, merging the Windows NT/2000 and Windows 95/98/Me lines. It used the Windows NT 5.1 kernel, bringing the NT core to the consumer market and replacing the Windows 9x branch. The initial release faced considerable criticism, particularly regarding security, leading to three major Service Packs: SP1 in September 2002, SP2 in August 2004, and SP3 in April 2008. SP2 provided significant improvements and encouraged widespread adoption among home and business users. Windows XP was one of Microsoft's longest-running flagship operating systems, from its public release on October 25, 2001, until succeeded by Windows Vista on January 30, 2007. Versions included Home Edition, Professional, XP N (without Windows Media Player as mandated by the European Union), Media Center Edition (MCE) released in October 2002 with subsequent versions in 2004 and 2005, Tablet PC Edition, Embedded, Starter Edition for developing countries, and Professional x64 Edition released on April 25, 2005, based on the Server 2003 codebase and using the x86-64 instruction set originally developed by AMD.

Windows 10 and corresponding Server versions

Windows 10 was unveiled on September 30, 2014, as the successor to Windows 8, and released on July 29, 2015. It was distributed without charge to Windows 7 and 8.1 users for one year. New features included Cortana, Microsoft Edge, the ability to view Windows Store apps as windows, the return of the Start menu, virtual desktops, revamped core apps, Continuum, and a unified Settings app. It was announced as a service OS receiving constant updates. Windows 10 received mostly positive reviews for stability and practicality but criticism for mandatory updates, privacy concerns, and advertising-supported software. Although Microsoft claimed it would be the last Windows version, Windows 11 was announced in 2021. Windows 10 lasted as Microsoft's flagship for six years, from July 29, 2015, to October 5, 2021, receiving thirteen main updates. Version 1507 (Threshold 1) introduced Windows Hello with facial recognition using a compatible near-infrared camera. Version 1511 (November Update, Threshold 2) added visual tweaks, the ability to activate with a Windows 7 or later product key, Find My Device, featured apps in the Start menu, and Edge improvements including tab previews and cross-device sync. Its kernel version was 10.0.10586.