Windows 10 is a major release of Microsoft's Windows NT operating system. It is the direct successor to Windows 8.1, which was released nearly two years earlier. It was released to manufacturing on July 15, 2015, and later to retail on July 29, 2015. Windows 10 was made available for download via MSDN and TechNet, as a free upgrade for retail copies of Windows 8 and Windows 8.1 users via the Windows Store, and to Windows 7 users via Windows Update. Windows 10 receives new builds on an ongoing basis, which are available at no additional cost to users, in addition to additional test builds of Windows 10, which are available to Windows Insiders. Devices in enterprise environments can receive these updates at a slower pace, or use long-term support milestones that only receive critical updates, such as security patches, over their ten-year lifespan of extended support. In June 2021, Microsoft announced that support for Windows 10 editions which are not in the Long-Term Servicing Channel (LTSC) will end on October 14, 2025.
Before version 1903, the pace at which feature updates are received by devices was dependent on which release channel was used. The default branch for all users of Windows 10 Home and Pro was \"Semi-Annual Channel (Targeted)\" (formerly \"Current Branch\", or \"CB\"), which received stable builds after they were publicly released by Microsoft. Each build of Windows 10 is supported for 18 months after its original release. In enterprise environments, Microsoft officially intended that this branch was used for \"targeted\" deployments of newly released stable versions so that they could be evaluated and tested on a limited number of devices before a wider deployment. Once a stable build is certified by Microsoft and its partners as being suitable for broad deployment, the build is then released on the \"Semi-Annual Channel\" (formerly \"Current Branch for Business\", or \"CBB\"), which is supported by the Pro and Enterprise editions of Windows 10. Semi-Annual Channel receives stable builds on a four-month delay from their release on the Targeted channel. Administrators can also use the \"Windows Update for Business\" system, as well as existing tools such as WSUS and System Center Configuration Manager, to organize structured deployments of feature updates across their networks.
In July 2017, Microsoft announced changes in the terminology for Windows branches as part of its effort to unify the update cadence with that of Office 365 ProPlus and Windows Server 2016. The branch system now defines two paces of upgrade deployment in enterprise environments, \"targeted\" initial deployment of a new version on selected systems immediately after its stable release for final testing, and \"broad\" deployment afterwards. Hence, \"Current Branch\" is now known as \"Semi-Annual Channel (Targeted)\", and \"Current Branch for Business\" for broad deployment is now referred to as \"Semi-Annual Channel\". 153554b96e