According to Pi Team there's also an improved audio power supply so the audio output sounds nicer - we don't have a schematic from the Pi Foundation yet, so we don't know precisely what changed
If you're recycling some older cable - you may have to experiment with which cable color is which output. Different camcorders/iPods had different pinouts for audio vs video so don't be surprised if "white" is video and "yellow" is audio. It is not harmful to experiment as the voltage levels for video and audio are similar.