http://arstechnica.com/apple/2014/06/report-apple-defines-specs-for-lightning-headphones-with-48khz-output/

Apple has created a new specification for its Made for iPhone (MFi) program that will allow OEMs to make headphones that use the Lightning port instead of the standard headphone jack, reports 9to5Mac. Headphones that use the specification will apparently be able to receive 48kHz digital stereo output, and headsets with integrated microphones will be able to send 48kHz digital mono input. The headphones could additionally send other kinds of input to the iDevice, including the ability to control playback or launch specific applications.