Hello. I have owned the Phantom 2 Vision for a little while now. Recently I've been thinking of upgrading the camera. Is it possible to upgrade by Phantom 2 Vision to a Phantom 3 or 4 camera and gimbal, or is that not possible? And if it is possible, what camera would you recommend?

No, it is not possible to upgrade to the P3 or P4 camera and gimbal. You would be better off looking for a good price on the P3 Pro, as its camera is almost as good as a P4 but the whole package is cheaper.

Correct as Geebax posted, you cannot upgrade the camera.

There are alternatives for adding after market but very expensive

http://dronexpert.nl/phantom-123-accessoires/