Apple iPhone Duo Apple has spent nearly two decades defining the iPhone as a single, fixed slab of glass and metal — and with the Duo, that definition finally changes. It's the biggest structural shift to the iPhone since the original launched in 2007, and it arrives at a moment when foldable phones from Samsung and Huawei have already had years to mature. We've detailed its features and use cases below. The Apple iPhone Duo , announced in September 2026 alongside the iPhone 18 Pro and Pro Max, is Apple's first foldable iPhone , opening book-style from a compact outer display into the largest screen Apple has ever put in an iPhone. The Duo is designed for early adopters and power multitaskers who want tablet-like screen real estate that folds away into a normal pocketable phone. 🔍 iPhone Duo: Detailed Features 📱 Design & Build Book-style foldable, titanium frame Machined and polished titanium construction, with a hinge designed for a fluid, continuous feel when op...