Apple's iPhone Duo introduces a foldable-optimized version of iOS 27 with redesigned navigation, seamless transitions between its two displays, Split View multitasking, flexible foldable modes, dual-screen camera features, and upcoming Apple Pencil support. While many ideas borrow from existing foldables, Apple's strength lies in refining the software experience, making the Duo feel like a cohesive blend of iPhone and iPad rather than simply a folding phone.