Microsoft is expected to begin rolling out Windows 10 2004 (the Windows 10 20H1 feature update) any day now. One of that release's biggest new features is the second version of the Windows Subsystem for Linux, WSL2. Just before release Microsoft is making a change to WSL2 that's designed to improve its "serviceability," officials said on March 13.
Specifically, Microsoft has decided to remove the Linux kernel from the Windows OS image with WSL2. Instead, the company will deliver it to users' machines using Windows Update. Users will be able to manually check for new kernel updates by clicking the "Check for Updates" button or by waiting for Windows to do this automatically.
"Our end goal is for this change to be seamless, where your Linux kernel is kept up to date without you needing to think about it. By default this will be handled entirely by Windows, just like regular updates on your machine," said Microsoft Program Manager Craig Loewen in a blog post today outlining the coming change.
Loewen noted that initially, Windows 10 2004 users and Insider testers using Slow Ring preview builds will temporarily need to manually install the Linux kernel. They'll receive within "a few months" an update that will add automatic install and servicing capabilities. (In fact, Slow Ring testers just got today, March 13, a new Windows 10 2004 test build, 19041.153, which includes this servicing change to WSL2.)
WSL is what lets developers run a Linux environment, including most command line tools, utilities and apps directly on Windows 10 and Windows Server. When Microsoft first introduced WSL in Windows 10 in 2016 WSL was more of an Linux interface at that point designed in partnership with Canonical. But Microsoft has been busy rearchitecting WSL with WSL 2 so that it actually will provide a Microsoft-written Linux kernel running in a lightweight virtual machine that's based on the subset of Hyper V. Users can put basically any Linux distribution of their choice on that kernel.