Windows 11 version history

Windows 11 is a major release of the Windows NT operating system developed by Microsoft that was released in October 2021. Starting with Windows 10, Microsoft described Windows as an "operating system as a service" that would receive ongoing updates to its features and functionality, augmented with the ability for enterprise environments to receive non-critical updates at a slower pace or use long-term support milestones that will only receive critical updates, such as security patches, over their five-year lifespan of mainstream support.

Overview
As with Windows 10 (since version 20H2), mainstream builds of Windows 11 are labeled "YYHX", with YY representing the two-digit year and X representing the half-year of planned release (for example, version 21H2 refers to builds which initially released in the second half of 2021).

Insider releases
Windows Insider Preview builds are delivered to Insiders in four different channels. Insiders in the Dev and Canary Channel receive updates prior to those in the Beta Channel but might experience more bugs and other issues. Insiders in the Release Preview Channel do not receive updates until the version is almost available to the public but are comparatively more stable.

On February 3, 2022, Microsoft changed its plans on how they delivered builds for Windows Insiders, with Dev and Beta Channels being "parallel" active development branches, giving an option to switch from Dev to Beta Channel for a limited time. The Dev Channel builds are meant for upcoming and experimental features that may never release to general availability, whereas the Beta Channel builds are the "feature complete" builds that will make its way to the general availability for the specific Windows 11 release.

On March 6, 2023, Microsoft announced that the Dev Channel will be rebooted, and existing insiders will be moved to the new Canary Channel. Two days later, insiders transitioned from Dev to Canary received the first build in the existing 25000 series builds starting from build 25314 while new insiders in the rebooted Dev Channel received the first build in the new 23000 series builds starting from build 23403.

Dev Channel
On September 2, 2021, Microsoft announced that Windows Insiders in the Dev Channel will receive builds directly from the rs_prerelease branch, which are not matched to a specific Windows 11 release. The first build released under this strategy, build 22449, was made available to Insiders on the same day.

Aside from the rs_prerelease (21H2 string) branch, Insiders in the Dev Channel would receive builds compiled from other branches within certain periods of time: ni_release (builds 22557 to 22616 – 22H2 string in former Dev), ni_prerelease (builds 23403 to 23620 – 22H2 string in rebooted Dev) and ge_release (builds 26052 to 26100 – 24H2 string) and TBA (build 26120 and later).

Canary Channel
Aside from the rs_prerelease (22H2 string) branch, Insiders in the Canary Channel would receive builds compiled from other branches within certain periods of time: zn_release (builds 25375 to 26040 – 23H2 string), ge_release (builds 26052 to 26100 - 24H2 string) and ge_prerelease (build 26200 and later).