Preview 4 of 4.12 has been released and this build includes a preview of the Editor in VR mode. This is a forward-looking feature that allows you to freely navigate your worlds in VR using motion controllers. You can also select and move actors, place new objects and even access the editor's UI, all while immersed in VR. This feature currently requires either an HTC Vive or Oculus Touch development hardware.
To download, go to the Epic Games Launcher and select the "Library" tab. Click "Add Versions" and choose 4.12 Preview 4. If you have a Preview version already installed, simply hit 'Update'.
Check out the updates included in this release through the latest forum post from Stephen Ellis. Also be sure to have a look at the known issues list. Remember these Preview builds are for testing only, please don't use them for the active development of your project.