"Hey Siri" support and possibly wireless charging case alongside AirPower charging mat.
AirPods and AirPower: Everything We Know
KGI: iPhone X Production Woes Ending, but Only 2–3 Million Units Available for Launch
According to Kuo, the biggest hurdle has likely been the flexible printed circuit board (FPCB) for the device's antenna, due to increased complexity and initial supply chain partner Murata's inability to meet specifications.
Special materials, recipes, design, processes, equipments and tests are required for antenna FPCB, as the specifications for iPhone X antenna (supplied by Amphenol (US)) are higher than those of iPhone 8 and only Murata (JP) and Career Tech (6153 TT, NT$30.1, NR) can meet Apple's requirements. Murata (originally with a 60% order allocation or higher) won't be able to resolve its issues before 2Q18, and thus has been fully replaced by second supplier Career. We believe Career will ramp up in November, as capacity expansion takes time, and its materials, recipes, design, processes, equipments and tests are different from those of Murata.A secondary bottleneck appears to have been the FPCB for the wide-angle rear camera lens. Unlike competing dual-lens camera smartphones from Samsung and Huawei, the iPhone X's wide-angle and telephoto lenses use separate PCBs, and supplier Interflex has reportedly struggled with quality issues on the part for the wide-angle lens.
The third bottleneck that has received signifcant attention in recent weeks is the TrueDepth camera's infrared dot projector, or the "Romeo" component. According to Kuo, previous design issues that led to poor facial recognition have been addressed and the "worst is behind us."
Overall, Kuo is cutting his iPhone X shipment estimates for the fourth quarter to 25–30 million units, down from 30–35 million, and he expects that 2–3 million units will be shipped into distribution channels ahead of the launch. As a result, initial supplies will be very tight, as has been extensively rumored. Kuo says shipments will "pick up markedly" in the first quarter of 2018.