Specifically, according to information provided on Apple's technical specifications page for the iPhone 15 lineup, these phones still support Qi wireless charging with power capped at 7.5W, while MagSafe charging is at 15W.
This iPhone 15 lineup still supports Qi wireless charging with a limited power of 7.5W. Image: Apple.comThe iPhone 15 lineup still only supports 7.5W Qi wireless charging. Image: Apple.com

Qi2 is known as the new wireless charging standard developed based on Apple's MagSafe charging. It includes a magnetic energy configuration to ensure smartphones are perfectly aligned with charging devices and aims to provide improved energy efficiency and faster charging.
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about the latest iPhone 15 informationcurrently
Some companies have announced Qi2 chargers capable of charging up to 15W like MagSafe, but it seems that Apple's iPhones will not support faster charging functionality. Apple also did not disclose whether they have improved the power output of MagSafe wireless charging technology on the new models or not.
Close-up of the iPhone 15 with a new USB-C port, featuring Dynamic Island and pink color.Check out more here!
According to 9to5Mac, the iPhone 15 models may support faster charging speeds when using a 35W charger, but Apple's technical specifications page does not list any improvements to the fast charging feature.