CES 2016 - HTC has just announced the new Vive Pre VR headset, which will be on its way to developers in the coming hours. Vive Pre is the next leap between the Vive prototype and the final consumer version, which will ship to consumers in April.
The second-generation kit is a more final version of the Vive, with the "most experimental technology and the least compromise" reports The Verge. HTC and Valve then delayed the Vive after they had reached a "very, very big technological breakthrough", which seems to be what the Vive Pre turned out to be.
HTC has added a front-facing camera to the Vive Pre, which provides a look into the real-world, when you're in the virtual one. When you are walking around with the Vive headset on, and you walk near a wall in the real-world, you'll be introduced to a "black-and-teal rendering of the real-world" to show that you're hitting the limits of the real-world.
Right now, the new front-facing camera doesn't have any advantages other than overlaying the real-world into the VR world, but I'm sure HTC and Valve, and the countless developers out there will make great use of the front-facing camera on the Vive in the very near future.