The leak of Windows 11 Build 21996 gave everyone a good idea about new features and changes that Windows 11 may pack over Windows 10. But, now a collated timeline gives us a good idea about two branches of Windows 11 aka Sun Valley update; co_release targeted at Summer’21 release and co_refresh targeted at Fall’21 in development.

The collated timeline has been created by a well-known Microsoft enthusiast “Albacore“. The timeline explains that in March 2021, Microsoft separated Windows 11 aka Sun Valley update development in two branches: “co_release” and “co_refresh”.

The “co_release” branch is where the Windows 11 Build 21996 belongs to. This branch was always targeted as a “Summer 2021 release” and with some touchups, co_release branch Build 22000 may be revealed by Microsoft on June 24 during the event. Microsoft will release Windows 11 for insiders on June 24 with Build 22000 as probably the first build.

The co_refresh branch is targeted at the Fall 2021 release. The branch had Build 22112 in development on May 31 as per the timeline. So, co_refresh builds will bring more Windows 11 features and changes to insiders up to September 2021 when the development will be completed. Microsoft may be planning to release Windows 11 to public in October 2021.

The timeline also reveals that development for the next major Windows update “Nickel” has started on March 29, 2021. It may belong to rs* branches and may be seeded to insiders once the development of Windows 11 is over in August/September 2021. The build for Nickel is said to higher than Build 22350.