Microsoft codenames are given by Microsoft to products it has in development before these products are given the names by which they appear on store shelves. Many of these products (new versions of Windows in particular) are of major significance to the IT community, and so the terms are often widely used in discussions before the official release. Microsoft usually does not announce a final name until shortly before the product is publicly available. It is not uncommon for Microsoft to reuse codenames a few years after a previous usage has been abandoned.
There has been some suggestion that Microsoft may move towards defining the real name of their upcoming products earlier in the product development lifecycle to avoid needing product codenames.
Operating systems
Windows 3.x and 9x Codename Preliminary nameFinal nameNotesRefJanusWindows & MS-DOS 5Combined bundle of Windows 3.1 and MS-DOS 5. Janus is a Roman god usually depicted with two faces, here symbolizing the previously separate Windows and MS-DOS products.Comes v Microsoft. Transcript of Proceedings, Volume XXXIV JastroWindows & MS-DOS 6Combined bundle of Windows 3.1 and MS-DOS 6. Portmanteau of Janus and Astro, the codename of MS-DOS 6.Comes v Microsoft. Deposition of Andrew Schulman, Volume 2Sparta, WinballWindows 3.1 PlusWindows for Workgroups 3.1Windows 3.1 (16-bit) with enhanced networking; designed to work particularly well as a client with the new Windows NT.SnowballWindows for Workgroups 3.11An updated version of Windows for Workgroups 3.1, which introduces 32-bit file access and network improvements. It also removes the Standard Mode, effectively dropping support for 16-bit x86 processors.ChicagoWindows 4.0, Windows 93, Windows 94Windows 95For codenames of some of the internal components of Windows 95, see "Jaguar", "Cougar", "Panther" and "Stimpy" under DetroitUSB Supplement to Windows 95 OSR2Named after Detroit, Michigan. A writer for Maximum PC suggested that "Detroit" and other Windows 95-era names were answers to the question posed by Microsoft's "Where do you want to go today?" marketing campaign.NashvilleWindows 96Named after Nashville. Cancelled upgrade for Windows 95; sometimes referred to in the press as Windows 96. Codename was reused for Internet Explorer 4.0 and Windows Desktop Update which incorporated many of the technologies planned for Nashville.Comes v. Microsoft. Plaintiff's Exhibit 3208 : "Desktop Operating Systems Mission Memo". Microsoft Confidential.Comes v. Microsoft. Plaintiff's Exhibit 5735 . Microsoft Confidential (October 25, 1995).MemphisWindows 97Windows 98United States v. Microsoft Corporation. Government Exhibit 202 : "C. Wildfeuer message re 'Memphis IE 4 focus groups report'"MillenniumWindows MeME stands for Millennium Edition; Microsoft states that it is pronounced Me.
Windows NT family +CodenamePreliminary nameFinal nameNotesRefRazzleNT OS/2, Advanced Windows Windows NT 3.1Is also the name of a script that sets up the Windows NT development environment. NT OS/2 reflected the first purpose of Windows NT to serve as the next version of OS/2, before Microsoft and IBM split up. Microsoft used the NT OS/2 code to release Windows NT 3.1.DaytonaWindows NT 3.5 Named after the Daytona International Speedway in Daytona Beach, Florida.CairoA cancelled project that would have fulfilled Bill Gates' "Information at your fingertips" visionShell Update ReleaseWindows NT 4.0WolfpackMicrosoft Cluster ServerJanusCodename for the proposed 64-bit edition of Windows 2000, which was never released.ImpalaWindows NT 4.0 EmbeddedNeptunePlanned to be the first consumer-oriented release of Windows NT succeeding the Windows 9x series; merged with Odyssey to form Whistler.TritonA cancelled successor to "Neptune".AsteroidWindows 2000 Service Pack 1OdysseyPlanned to be a successor to Windows 2000; merged with Neptune to form Whistler.WhistlerWindows 2002Windows XPNamed after Whistler Blackcomb, where design retreats were held.MantisWindows XP Embedded Named after the Mantis shrimp.FreestyleWindows XP Media Center EditionHarmonyWindows XP Media Center Edition 2004SymphonyWindows XP Media Center Edition 2005SlalomLonghorn Media Center Edition. Scrapped in favor of including Windows Media Center in Home Premium and Ultimate editions instead of a dedicated Media Center edition.EmeraldWindows XP Media Center Edition 2005 Update Rollup 2DiamondWindows Media CenterIncluded with Windows Vista.SpringboardSet of enhanced security features, included in Windows XP Service Pack 2.LonestarWindows XP Tablet PC Edition 2005Whistler ServerWindows 2002 Server,Windows .NET Server,Windows .NET Server 2003Windows Server 2003BobcatWindows Small Business Server 2003Not to be confused with Microsoft Bob.Eiger, MönchWindows Fundamentals for Legacy PCsMönch included additional features for use on mobile devices.LonghornWindows VistaNamed after the Longhorn Bar in the Whistler Blackcomb ski resort; initially planned as a "minor release" between "Whistler" and "Blackcomb" (see below)Blackcomb, ViennaThe purported successor to Whistler, and later, Longhorn. Named after Whistler Blackcomb, where design retreats were held. Blackcomb was later renamed to Vienna in January 2006, named after the capital of Austria. Eventually cancelled due to scope creep and replaced with Windows 7.Q, QuattroWindows Home ServerVailWindows Home Server 2011Longhorn ServerWindows Server 2008CougarWindows Small Business Server 2008CentroWindows Essential Business ServerNamed after the Spanish translation of the word "center".7Windows 7The number 7 comes from incrementing the internal version number of Windows Vista (6.0) by one. Often incorrectly referred to as Blackcomb or Vienna, while the codenames actually refer to an earlier Vista successor project that was cancelled due to scope creep.Windows Server 7 Windows Server 2008 R2Solution Server Windows MultiPoint Server 2010 Windows MultiPoint Server "2" Windows MultiPoint Server 2011 FijiWindows Vista Media Center Feature Pack 2008Windows Media Center TV Pack 2008Named after the country of Fiji.Cascades Windows Essential Business Server "v2"Windows Essential Business Server 2008 R2 (cancelled)Originally intended as the successor of Windows Essential Business Server 2008 but was cancelled "due to external factors".AuroraWindows Small Business Server 2011 EssentialsQuebecWindows Embedded Standard 7Named after the province of QuebecWindows 8Windows 8Often incorrectly referred to as Jupiter, Midori and Chidori. Jupiter is the application framework used to create "immersive" apps for Windows 8, and Midori was a separate, managed code operating system. (see below) Windows Server "8" Windows Server 2012 Blue Windows 8.1 Windows Server Blue Windows Server 2012 R2 ThresholdWindows 8.2, Windows 9 Windows 10Windows 10 November Update Named after a location seen in Halo: Combat Evolved, near which Installation 04 orbits. Redstone Windows Server 2016Windows 10 Creators UpdateWindows 10 Fall Creators UpdateWindows 10 April 2018 UpdateWindows Server 2019 Named after a fictional mineral from Minecraft. Santorini Windows 10X Named after an island in Greece. Originally supposed to be a new OS to be released mid-late 2021, was eventually cancelled. Some of its features were integrated into Windows 11 and other products. Sun Valley Windows 11Named after Sun Valley, Idaho. Hudson Valley Windows 11, version 24H2 Named after Hudson Valley, New York. "Microsoft is already preparing the next big update for Windows 11 for the end of 2024, codenamed “Hudson Valley”, with a bigger focus on AI."
Windows platform development semesters The following are code names used for internal development cycle iterations of the Windows core, although they are not necessarily the code names of any of the resulting releases. With some exceptions, the semester designations usually matches the Windows version number.
Codename Semester Release Notes Ref Titanium 19H1 Windows 10 May 2019 Update Named after the chemical element in the periodic table. Vanadium 19H2 Windows 10 November 2019 Update Named after the chemical element in the periodic table. Vibranium 20H1 Windows 10 May 2020 UpdateWindows 10 October 2020 UpdateWindows 10 May 2021 UpdateWindows 10 November 2021 UpdateWindows 10 2022 Update Named after the fictional metal Vibranium in Marvel Comics as continuing the previous line of chemical elements with Chromium could have caused confusion with the web browser project. Manganese 20H2 Named after the chemical element in the periodic table. Iron 21H1 Windows Server 2022 Named after the chemical element in the periodic table. Cobalt 21H2 Windows 11 Named after the chemical element in the periodic table. Nickel 22H2 Windows 11 2022 Update Windows 11 2023 UpdateNamed after the chemical element in the periodic table. Originally planned to be the 22H1 semester, although that semester was ultimately skipped and Nickel shifted to 22H2, expanded to span the entire year. Copper 23H1 Named after the chemical element in the periodic table. Zinc 23H2 Windows Server, version 23H2Named after the chemical element in the periodic table. Gallium 24H1 Named after the chemical element in the periodic table. Germanium 24H2 Windows 11 2024 UpdateWindows Server 2025Windows 11 2025 UpdateNamed after the chemical element in the periodic table. Dilithium 25H1 Named after the fictional material from Star Trek. Selenium 25H2 Named after the chemical element in the periodic table. Bromine 26H1 Named after the chemical element in the periodic table.Krypton26H2 Named after the chemical element in the periodic table.
Windows CE family CodenamePreliminary nameFinal nameRefPegasus, Alder Windows CE 1.0 Birch Windows CE 2.0 Cedar Windows CE 3.0 Talisker Windows CE .NET Windows CE 4.0 Jameson Windows CE 4.1 McKendric Windows CE 4.2 Macallan Windows CE 5.0 Yamazaki Windows CE 6.0 Windows Embedded CE 6.0 Chelan Windows Embedded CE 7 Windows Embedded Compact 7
Windows Mobile CodenamePreliminary nameFinal nameRefRapierPocket PC 2000MerlinPocket PC 2002OzoneWindows Mobile 2003MagnetoWindows Mobile 5CrossbowWindows Mobile 66 on 6Windows Mobile 6.1.4TitaniumWindows Mobile 6.5MaldivesWindows Mobile 7Windows Phone 7
Windows Phone CodenamePreliminary nameFinal nameRefPhotonWindows Mobile 7 SeriesWindows Phone 7Mango Windows Phone 7.5Apollo Windows Phone 8Blue Windows Phone 8.1Threshold Windows 10 Mobile
Others CodenamePreliminary nameFinal nameNotesRefSingularityExperimental operating system based on the Microsoft .NET platform, using software-based type safety as a replacement for hardware-based memory protection. Evolved into Midori. Midori A managed code operating system being developed by Microsoft with joint effort of Microsoft Research. Red DogWindows CloudAzureMicrosoft cloud services platformTahitiSupposedly a family of multi-core technologies including an operating system, applications and development tools designed to make better use of today's multi-core CPUs. Midori may be a part of this suite of new Microsoft technologies.TokyoAzure AD Cloud App DiscoveryCloud App DiscoveryAzure-based data-directory service designed to help connect the right people to the right data.Zurich.NET ServicesPart of Microsoft Azure, Microsoft's cloud computing platform, that focuses on extended software development based on .NET Framework to the cloud.
OS components