Apple has unveiled the iPhone Duo, its first foldable phone, marking the company's first genuinely new product category in some time. The launch, unveiled by new CEO John Ternus during his debut keynote, sees Apple entering a niche but growing market — foldables made up just 1.6% of global smartphone sales last year, according to Counterpoint Research — following a familiar pattern of arriving late to categories such as tablets and smartwatches before attempting to popularise them.

The Duo folds to a "passport sized" 5.4-inch screen and opens to 7.6 inches, slightly smaller than the iPad mini, and will cost $1,999. Apple touts a reinforced hinge with over 100 components, a titanium rear plate, and IP68 dust resistance, though durability claims for foldables have historically fallen short in practice, and skeptics note Samsung's eight generations of Galaxy Fold still struggle with hinge longevity. The device drops Face ID for a side-mounted Touch ID button, has two cameras rather than three, and shifts iOS navigation controls to the side of the screen to suit its wider format — a change that will require developers to adapt their apps via a new API, echoing ongoing struggles with app support for Apple's revamped Siri.