Microsoft never sleeps. Even before the Windows 10 November 2019 Update (version 1909) started to roll out, the company began working on upcoming feature updates to Windows 10. As it did with version 1909, Microsoft has been releasing a series of public preview builds to members of Microsoft’s Windows Insider Program.
In December 2019, Microsoft also changed how its Insider rings work: Now the Fast ring is where new features are introduced for testing, regardless of which Windows 10 release they’ll eventually end up in. The Slow ring is where you’ll get more polished features that will be deployed in the next Windows 10 feature update; at the moment that’s Windows 10 20H1. And the Release Preview ring usually doesn’t see action until shortly before a new feature update is rolled out; it’s meant for final testing of an upcoming release.Below you’ll find information about preview builds that have been released to the Fast ring, followed by preview builds specifically for 20H1. For each build, we’ve included the date of its release, which Insider ring it was released to, a summary of what’s in the build, and a link to Microsoft’s announcement about it. After that you’ll find summaries of all the preview builds that led up to prior feature updates, from the November 2019 Update (version 1909, code-named 19H2) on back to the Windows 10 Creators Update (version 1703, code-named Redstone 2).
After years of using “Redstone” in its code names for upcoming releases, Microsoft switched to a new format with version 1903, released in May 2019. The code names now use a YYH1/YYH2 format, with the YY standing for the last two numbers of the year and H1 or H2 referring to the first or second half of the year. So Windows 10 version 1909, which was released in November 2019, was code-named “19H2” (for second half of 2019). The next feature update, due in the spring of 2020, is code-named 20H1.[ Further reading: Windows 10 update (and retirement) calendar: Mark these dates ]