Apple may be limiting fast charging for the 2018 iPhone lineup for specifically certified chargers, according to a new report from Japanese site Mac Otakara (via 9to5Mac). Although fast charging came to the 2017 iPhone lineup last year — and the iPad Pro before that — via the USB Power Distribution (USB-PD) standard, the new report suggests that Apple may be taking steps to ensure that only certified chargers will work by requiring that they support USB Type-C Authentication (C-AUTH), a newer standard that’s designed to protect against non-compliant USB chargers. According to the report, connecting to a charger that doesn’t support C-AUTH will limit the power draw to a mere 2.5 watts (0.5 amps) — the basic power draw supported by the original USB standard, and half the speed of the five-watt charger that Apple has traditionally bundled with new iPhones. Of course, is recent reports are accurate, Apple will be bundling the 18-watt power adapter with all of the 2018 iPhone models, so the issue will only affect users looking to pick up an additional power adapter — and with C-AUTH being supported by dozens of companies (and over a thousand belonging to the USB Implementers Forum), compliant fast chargers should be available from a number of different companies.