Federico Viticci 
In case you're wondering:
The iPhone Air battery is recognized by my iPhone 16 Pro Max running iOS 26 RC.
It does not stay attached. But when placed, it charges the phone.
Eshu Marneedi@viticci If I had to guess, it’s probably because the Air battery uses the same chip/firmware as the MagSafe Battery Pack from many moons ago, which is still supported in iOS. Aside from the size, it’s basically unchanged.