Until today, Windows 10 users who wanted to work with the new Windows Subsystem for Linux version 2 needed to have the latest feature update for Windows: The Windows 10 May 2020 Update (aka Windows 10 2004). But on August 20, Microsoft made a surprise announcement: WSL2 has been backported to Windows 10 1903 and 1909, as well.
Microsoft's rollout of Windows 10 2004 has been slow. And a number of business users tend to skip the spring/H1 Windows 10 feature updates and focus on the fall/H2 ones, which are supported for longer and get more real-world testing. This is the audience that is likely most interested in WSL2, so making WSL2 available on 1909 looks like a smart move.
Officials said in a blog post today that Microsoft has been working on bringing WSL2 to 1903 and 1909 "over the last few months." They said the goal is for the backport to make WSL2 available to more Windows users. The 1903/1909 backport will be for x64 systems only; those using ARM64 need to use Windows 10 2004 to get WSL2.
WSL is a much-reworked version of the original WSL. It changes how Linux distributions interact with Windows. As officials noted in today's post, each Linux distribution running on Windows 10 can run as WSL1 or WSL2 and can be switched at any time.
WSL2 provides a full Linux kernel built into WSL2; improved system call support for all Linux apps, including Docker, FUSE, rsync, and more; and improved file system performance, according to Microsoft.
Officials remind users: "This backport has the minor build number: 1049. To summarize, if your minor build number is 1049 or higher on Windows builds 18362 or 18363, then you have the backport and the ability to run WSL 2 distros."