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.
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.