By now we know that vivo's next NEX flagship, the vivo NEX 2, will have two screens - a large bezel-free 6.59-incher on the front and a 5.5" unit on the rear. What we now know is how vivo engineers thought out the process of toggling between the two and it doesn't involve any mechanics whatsoever.
All it takes is a three-finger swipe on the active screen (whether front or back) to activate the opposite one.
The vivo NEX 2 is still quite new in the the rumor mill but we've already seen itin the wild twice. We know all the phone's cameras will be above the rear screen but we can only guess what all of them will be used for.
We assume the vivo NEX 2 will run a Snapdragon 845 with up to 8GB of RAM, like the vivo NEX S. We also expect the vivo NEX 2 to become official sometime in early 2019 - perhaps at the Mobile World Congress in late February.