A few days ago Appleinsider reported that the FCC has been working on the certification for a yet-to-be-announced Beats Solo 2 wireless headphones:

The U.S. Federal Communications Commission on Friday published testing results for the as-yet-unannounced Beats Solo2 Wireless headphone, a Bluetooth-enabled version of the Apple-owned company’s mid-tier Solo2.

This announcement is likely the first hint we are getting that the 3.5mm headphones jack is on its way out on future Apple devices. The iPhone is a good candidate as the first Apple device to be released without a standard headphones connector. 

In his iPhone 6 review, 512pixels wrote:

The headphone jack is the thickest opening on the phone. It’s not hard to imagine that in the future this is going to limit what Apple can do thickness-wise.

Apple’s quest for thinner devices is now hindered by the physical size of a standard connector. In the same way Apple ditched the 30-pin connector in favour of the new Lightning interface, in one-two years it’s likely that we will be using iPhones without a headphones jack.