The Flux app got pulled from the app store because it was using private APIs. What APIs and how do you access private APIs? IS there a list of private APIs somewhere? If converting Kelvin temperature is a normal function for weather and other apps why was it banned? I guess the API is directly related to the brightness settings? So the API is the API that controls display brightness? [[UIScreen mainScreen] setBrightness:0.1] ???? How do you control Kelvin temperature settings in Swift/Obj-C?