Microsoft Is Backporting WSL2 To Their Windows 10 2019 Releases
WSL2 as a HyperV-powered more VM-like Windows Subsystem for Linux rolled out officially in the Windows 10 May 2020 Update. Microsoft though has now back-ported WSL2 to their Windows 10 November 2019 and May 2019 updates.
WSL(1) has been available in the Windows 10 2019 releases while Microsoft decided to backport WSL2 for those enterprise customers still relying upon these pre-2020 versions of Windows.
This should be particularly beneficial for those enterprises running Windows 10 1903/1909 with WSL but have been disappointed by the poor I/O performance. One of the major benefits to WSL2 besides forthcoming GPU acceleration and other features is simply offering much faster I/O compared to that major bottleneck in the original WSL due to differences in how file I/O operations are handled.
WSL2 is available for these prior 2019 versions of Windows 10 via the Windows Update KB 4566116 and carrying out the additional steps for actually enabling the WSL2 functionality.
More details on making use of WSL2 in these versions of Windows 10 can be found via the Ubuntu blog.