Microsoft Xbox One Controller To Gain Standard Headphone Port
The support page provides an overview of the Xbox One controller, including a pair of diagrams that are labeled with 16 points of interest, plus the four X-Y-A-B buttons. On of the bottom of the controller is point number 16 for a 3.5mm port, something that doesn't exist on current generation controllers.
"3.5mm port (16). Used to connect compatible 3.5mm audio devices. Only available on controllers released after June 2015," Microsoft states on the Xbox One controller's support page.

In terms of audio connectivity, the upcoming change will bring the Xbox One controller on par with Sony's DualShock 4. Meanwhile, owners of existing Xbox One controllers who don't plan to upgrade can buy a Microsoft's Stereo Headset Adapter, a $25 accessory that plugs into the controller's USB port.
Microsoft hasn't yet announced the new controller (perhaps at E3?), so it's known if there will be other changes to the design or functions outside of adding an audio jack.