Windows Insider Program

Windows Insider Program is an initiative by Microsoft that allows users of Windows 10, Windows 11, and Windows Server to opt into testing out new, unfinished versions of the operating system. The first build to be publicly released via the Insider Program was Windows 10 build 9841.

Channels
The Insider program allows users to pick the builds they want to receive by enrolling to a specific channel. The Insider infrastructure is also used for Microsoft's internal selfhosting effort, with internal channels receiving builds both before and after the public channels; however, they are not a formal part of the Insider program. Currently, the Insider program offers the following channels:
 * Canary Channel, which receives pre-release builds of the latest engineering milestone.
 * Dev Channel, which receives builds from the pre-release branch of the latest Windows 11 feature update.
 * Beta Channel, which receives work in progress updates from the release branch of the latest Windows 11 feature update.
 * Release Preview Channel, which receives finished updates prior to their general rollout to consumers. It is the only channel to receive new pre-release Windows 10 updates since the release of Windows 11.

History
The Windows Insider Program launched on 1 October 2014 together with the release of the first Windows 10 Technical Preview, build 9841. Unlike most prior testing programs, which tended to be limited only to select developers and/or partners, the Insider program is fully open to the public. Originally, the program used a system where each build was tested by gradually increasing audiences called rings. If a build was deemed stable enough by a ring, it was released to the next ring, eventually reaching the public Insider rings. The following rings were in place in 2015:
 * Canary - daily builds from the release branch or many internal branches
 * OSG/Selfhost - the entire Operating Systems Group
 * Microsoft - all Microsoft employees
 * Insider Fast - first public ring
 * Insider Slow - second public ring

A third public ring, the Release Preview Ring, was added in February 2016. However, unlike the Fast and Slow Rings, it did not receive pre-release content but rather allowed enrolled users to receive finished updates prior to their general rollout to all users. At some point, the Microsoft ring was moved behind the Fast Ring, which allowed for the Fast Ring to receive builds more frequently. The frequency eventually increased from one build per month in 2014 to weekly drops in 2017. In July 2017, the Skip Ahead option was introduced for users enrolled in the Fast Ring, which was activated during the final stages of development of a release and allowed a limited number of users to receive early builds of the next release, while the rest kept receiving builds of the nearly finished release. Skip Ahead was later discontinued in November 2019.

In August 2020, Microsoft announced a complete overhaul of the Windows Insider Program. Builds no longer had to pass through several rings, but different tracks of release would be continually offered through what was now called 'channels'. Several channels were set up:


 * Dev Channel: Builds were generally released weekly and tracked the next major release until RTM, when it would then jump to the next major release.
 * Beta Channel: Builds were generally released weekly and tracked the next major release from a point near RTM until GA, when it would then jump to the next major release. It periodically synced with Dev so users could jump between them without having to clean install. For Windows 10 2022 Update and later, it tracked the development cycle of "moments".
 * Release Preview Channel: Usually the same builds as Beta Channel after a Windows version RTMed, but without enablement packages used to turn on Beta Channel specific features.

This model continued for the Windows 10 20H2 through Windows 11 2022 Update Moment 2 releases, until 6 March 2023, when a new model was announced. The Dev channel was split into Dev and Canary, where Dev was moved down to test previously internal Moment builds, and Canary was added, which flights far more frequently than weekly (wait until it starts flighting to determine).