Valve has updated the Steam Beta client to include Virtual Reality Mode. The update was added yesterday, and will now show up in the View menu, with the firm stating that it has removed the –vr command line option. This will only appear if SteamVR is installed and if a supported HMD is detected. Also added was support for switching from desktop mode to VR, then back to desktop and into Big Picture. Support for detecting when an HMD has been plugged in after Steam has started was also added. The full list of updates can be found through here.