For two years now Apple has abandoned the 3.5 mm jack in favor of the only lightning port (at least on the iPhone). So far, however, had made a good face of a bad game including the lightning-jack adapter. It seems that this practice will die with the iPhone 2018.
The “premonition” was born as early as April with the analysis of Barclays. Today, however, the rumors are strengthened, because Cirrus Logic, the company that provides the adapter to Apple, would have confirmed the lack of the dongle in the packaging of the next iPhone.
Apparently, Apple is trying to focus as much as possible on the spread of wireless headphones (such as AirPods that will be renewed next year). This decision will turn up their noses to cable fans, however, at least, the adapter will continue to be sold separately (at a modest sum of € 9).