Apple upset the old, er, apple cart by removing the headphone jack from the iPhone 7. Other smartphones like the Moto Z Droid have also removed the analog headphone jack from their devices. It's a trend that's sure to continue as companies make slimmer and more durable smartphones with hermetically sealed moisture-resistant designs.
So other than going wireless with a headphone that offers Bluetooth connectivity, the sole option is to connect a headphone to the newest Apple iPhones using their proprietary 'Lightning' cable.
Although we expect the selection of Lightning-compatible wired headphones, amps and accessories to increase exponentially over the next few months and years, there are several great products ready now for Apple users wanting excellent sound for their Lightning-equipped devices.