Delving through the iOS 8 beta, it shows that Apple is enabling headphones to be connected via the lightning port.
I see this as the next step to Apple removing the headphone jack. It is viable as audio can be pumped out via the lightning port. Non lightning headphones could have an adapter in the box.
However, I don’t think Apple will remove the headphone port so quickly, but they will allow high definition audio eg FLAC coded audio files to be played in the digital format to new hitech headphones. Or just a higher bit rate audio file to play directly to the headphones to enable a better listening experience.
Another option is just to enable docks to connect to allow high audio quality playback.
September 2014 will reveal all when Apple announces the new iPhone and iPad.
Update. Apple has just released guidelines for the lightning port.
“Apple has just published all the “Made for iPhone” guidelines to bring lightning headphones to iOS devices. This Lightning headphone protocol will be capable of receiving lossless stereo 48 kHz digital audio output from Apple devices and sending mono 48 kHz digital audio input. It will allow microphone functionality, remote controls, and developers can even code apps to launch when headphones are connected”