2018 iPhones may only support fast charging from certified chargers

Apple may restrict fast charging of the 2018 iPhone models to certified chargers. 

According to Japanese site Macotakara, multiple supply chain sources claim that fast charging for the upcoming iPhones are limited to certified chargers. Even if a third party charger offers 18W, the new iPhone may limit its power draw to just 2.5W if the charger and charging cable do not meet the USB Type-C authentication standard.

It is important to note that this restriction does not mean that you can only use Apple chargers and cables. The USB Type-C authentication standard is currently supported by more than 50 companies.

Apple is rumored to be shipping a new 18W USB-C adapter for the iPhone later this year. ChargerLab has published purported renders of the USB-C adapter which reveal a smaller form factor compared to Apple's current USB-C power adapters. The new 18W USB-C adapter is also said to be exclusive to the 2018 iPhone lineup at launch.

Source: Macotakara via 9to5Mac