Will any of the latest HDMI features require a new cable?

Yes. The HDMI Ethernet Channel (HEC) feature will require a new cable that supports this functionality and it will also work as a regular HDMI cable. The Automotive Connection System is a cabling specification designed for use in a car and is capable of handling high heat, vibration, and noise. All of the other new HDMI features are compatible with the existing categories of cables.