Phase 1: The first radical design was the iPhone 1. Phase 2: iPhone 3G added internal features iPhone 3GS added internal features Phase 3: iPhone 4 kept the rectangular display and home button. changed the design around the screen which went from traditional to high definition display iPhone 4 added internal features iPhone 5 added screen performance and internal performance improvements iPhone 5S had same design and introduced TOUCH ID Phase 4: iPhone 6 had the same overarching rectangular design with home button just bigger and wider than previous iPhones iPhone 6S was the same with speed and 3D touch iPhone 7 was the same with speed and removed headphone jack and introduced wireless airpods iPhone 8 was the same outside with speed and glass back with internal improvements Phase 5: iPhone X brings almost the same internals as iPhone 8 with the first move away from LCD since the original iPhone, First time an iPhone does not have a home button, first time the iPhone screen is not completely rectangular, and first time the screen goes around the entire bezel edges of the phone. First time Apple has replaced a Gold standard feature *Touch ID* with what it believes is the future of security *Face ID*. with iPhone 7, the removed headphone jack meant nothing was added to replace it in the same box but with iPhone 10, we have an actual replacement of a major feature since the first iPhone.