According to bloomberg, the next generation of iPhone is already in production and it will have the force touch display, just like the apple watch and the newest macbook. This feature allows users of set up different functionality with different strength of their screen taps (pressure sensitive displays).
The cupertino gaint is said to be working on this technology for past couple of years to make it perfect. And the new iPhone(s) will have similar exterior design and screen sizes.
There are many rumors stating that the camera bump will disappearing in the next iPhone, a new rose gold color variant of the device by Apple, will come with 2GB of RAM, a 12 megapixel camera, A9 processor, an improved Touch ID sensor with different gesture support, and a stronger aluminum body construction.