Shipments of the iPhone X are estimated to reach between 30-35 million units in the fourth quarter of 2017 and stay flat or drop slightly in the first quarter of 2018, according to sources from the semiconductor packaging and testing service industry.

The sources pointed out that the pre-orders for the iPhone X in a number of markets such as Taiwan, the US and Singapore, are not as strong as expected, but they are seeing Apple Watch sales fare rather well. For 2018, the sources expect Apple Watch shipments are likely to reach 27 million units, higher than the previous' forecast of 23-25 million.

However, for some markets such as Japan, the iPhone X is still reported to have experienced tight supply.

Because of the iPhone X's weak performance, the upstream supply chain has been rumored that Apple is planning three new smartphones for 2018 with two using OLED displays and one LCD display, and the 3D sensing functionality may be more broadly used in these devices. Apple is also rumored to adjust its pricing for iPhone devices in early 2018 and has even started preparing a prototype iPhone with support of pre-5G features. However, Apple has not officially confirmed any of the rumors.