Traditionally, Microsoft supports Windows Server for 10 years, with five years of mainstream support and an additional five years of extended support. Between 2015 and 2021, Microsoft referred to these releases as “long-term support” releases to set them apart from semi-annual releases.

For sixteen years, Microsoft released a major version of Windows Server every four years, with one minor version released two years after a major release. The minor versions had an “R2” suffix in their names. In October 2018, Microsoft broke this tradition with the release of Windows Server 2019, which should have been “Windows Server 2016 R2”. Windows Server 2022 is also a minor upgrade over its predecessor.

Following the release of Windows Server 2016, Microsoft attempted to mirror the lifecycle of Windows 10 in the Windows Server family, releasing new versions twice a year which were supported for 18 months. These semi-annual versions were only available as part of Microsoft subscription services, including Software Assurance, Azure Marketplace, and Microsoft Visual Studio subscriptions, until their discontinuation in July 2021. The semi-annual releases did not include any desktop environments. All Semi-Annual releases are now unsupported.