updated 11:41 am EDT, Wed July 16, 2014
Part little different from iPhone 5s incarnation
New photos depict what is said to be the Touch ID sensor for iPhone 6. The part is compared with its equivalent for the iPhone 5s, and appears to be little different, except for a change in where screw holes are located. That's presumably needed to accommodate the phone's new proportions, scaled up to fit a 4.7-inch screen.
Touch ID isn't expected to evolve much for the iPhone 6. Sensors may become more durable, but have always been predicted to retain their current size and shape. The biggest change will come through software, since Apple is opening up Touch ID authorization to third-party apps.