https://www.techradar.com/news/windows-mixed-reality-gets-performance-boost-and-more-with-exit-from-steamvr-early-access

As you may have noticed, the Windows 10 April 2018 Update has been officially released by Microsoft, and with it comes a raft of Windows Mixed Reality improvements – and the news that Windows Mixed Reality for SteamVR has left ‘early access’.

In other words, this is effectively saying that a full range of functionality is now in place. As Valve notes, SteamVR has been available to those with Windows Mixed Reality headsets since last November, and testing has been ongoing on the aforementioned new features, with 24 updates having been released to beta testers.