While the sensors and the lenses stay the same - f / 1.8 and f / 2.8 sensors respectively - the new model benefits from a new image signal processor inside. (pocket-lint.com)
With the digital signal processor placing the sweet spot for the music dead center in the cabin, the audio actually sounded best in the back seat. (cnet.com)
The image signal processor also detects people, motion, and lighting conditions in a scene to optimize photos before they're taken. (macrumors.com)