f.lux is a popular screen color temperature adjustment software on Mac devices, its developer have been trying to convince Apple to allow its launch iOS version, but with little success, as the recently released iOS 9.3 with Night Shift feature, which designed to cut down on nighttime blue light exposure from iOS devices to encourage better sleep. f.lux app for Mac also has a similar function, to launch an iOS version, the behind developer issued an appeal to Apple once again.
Few months ago, the team launched F.lux beta for iOS, but Apple quickly rejected the application.
Because iOS does not have the necessary documented APIs to allow f.lux to function, f.lux was skirting the App Store with private APIs and asking users to install its iOS app through Xcode, using a technique called side-loading. Apple has now informed f.lux that asking people to side-load apps onto their iOS devices violates the Developer Program Agreement, so f.lux can no longer be installed on iOS devices using Xcode.
f.lux developer appealed in an official statement, Apple should allow them to release an iOS version for f.lux app and allows f.lux has the same rights and API with Night Shift function, support their team for further study of sleep and circadian clock.
We’re proud that we are the original innovators and leaders in this area. In our continued work over the last seven years, we have learned how complicated people actually are. The next phase of f.lux is something we cannot wait to ship to the world. […]
Today we call on Apple to allow us to release f.lux on iOS, to open up access to the features announced this week, and to support our goal of furthering research in sleep and chronobiology.
Obviously, this time f.lux hoping to take this opportunity to let apple open APIs to control display temperature. Currently on a non-jailbroken iOS device, users can not adjust the screen color temperature.