iPhone 7 to go wireless and waterproof
iPhone 6s and 6s Plus displayed at an Apple media event in San FranciscoReuters

Code buried deep within Apple's own iOS software suggests the iPhone 7 will not have a headphone jack. The revelation correlates with growing rumours that the next iPhone will ditch the 3.5mm port, instead forcing buyers to use Bluetooth or the Lightning connection for their headphones.

Discovered in the 1.1 public beta of iOS 9.3, which will be made more widely available soon, the code states "headphones.have.%sinput.NO." which, in plain English, suggests Apple is preparing for iOS to be used on a phone with no headphone input. The discovery was made, and posted to Twitter, by iOS developer Chase Fromm.

Fromm's tweet, discovered by Phonearena, includes a screenshot of the iOS 9,3 beta source code. Removing the headphone jack from the current iPhone 6S design would give Apple space to make the iPhone 7 even thinner and, taking the role of a cynic, give the tech firm the opportunity to sell a range of wireless or Lightning headphones under its Beats brand.

This move may sound drastic but Apple has a habit of removing technology earlier than its rivals. Doing away with the floppy disc drive and CD drive were seen as bizarre moves at first but the competition soon followed Apple's lead. The same could become true with the ubiquitous 3.5mm headphone jack.

A range of headphones that plug into the iPhone's Lightning port are already on sale, and so too are a large number of wireless Bluetooth headphones. We should learn the outcome later in 2016, as the iPhone 7 is tipped to be announced at a press event in September.