The developer briefly hosted an Xcode project on GitHub, allowing iOS 9 users to sideload the application onto their devices, but retracted it at the request of Apple. Apple has not allowed the application in its App Store due to its use of restricted developer tools. It is also available for iOS devices, although it requires the device to be jailbroken. The program is available for Microsoft Windows, macOS and Linux (except for Ubuntu 18.04 LTS).
The program can control Philips Hue LED lighting, so that the color temperature of house lights follows f.lux's settings. Times can be inverted on f.lux for PC to provide warm lighting during the daytime (for people who work at night). į.lux offers a variety of color profiles and pre-defined temperature values, modifying program behaviour for specific programs or activities including a mode for film watching, decreasing red tinge (for 2.5 hours), and a darkroom mode that does not affect night-adapted vision. At sunset, it will gradually change the color temperature to a warmer color and restore the original color at sunrise.
The program then automatically calibrates the device display's color temperature to account for time of day, based on sunrise and sunset at the chosen location. Upon installation, the user can choose a location based on geographic coordinates, a ZIP code, or the name of a location.
