MacRumors received a tip about the new feature from accessory maker RAVpower this evening, and tested the new charging speeds to confirm. Under the iOS 11.1.1 version, which was released last week, the iPhone 8, 8 Plus and iPhone X can charge at 5 watts using the Qi chargers.
MacRumors' testing suggested a slightly faster charge. Using a non-7.5W wireless charger topped the same iPhone X from 46% to 60% in over 30 minutes, which speaks of marginal gains here and there, but gains nonetheless. Still, wireless charging is markedly slower than direct charging via USB cable, and even with that boost to 7.5 watts, the iPhone 8 and iPhone X will charge more slowly using wireless charging pads compared to the Samsung Galaxy S8, which supports 9-watt quick-charging with the proper charging pad (though it's still considerably slower than wired charging).
If you're about to buy wireless chargers for the iPhone, make sure they support at least 7.5W speeds. It will, it's said, upgrade the 2017 iPhone range's wireless charging power support to 7.5W.
We first heard that iOS 11.1 would enable 7.5W wireless charging, which is the maximum speed you can expect for wireless chargers. Liang Chen earlier projects include a jailbreak for iOS 11 beta 2 and iOS 10.3.2 that never launched publicly.