With iOS 9, it is now possible to install screen brightness app Flux (or f.lux). Flux adjusts screen brightness and color depending on the time of day automatically, so you aren’t blasted with bright light at bedtime or early in the morning. Due to App Store restrictions, Flux has been only available on the Mac OS X platform until now. Whilst it isn’t available through the App Store, you can now download and install the Flux beta for iPhone and iPad by sideloading the app through Xcode on the Mac.

It sounds complicated but it’s actually really easy to do. Apple lifted the developer limitations on device app sideloading earlier this year, so it’s completely free. Until Apple relaxes App Store policies, this will be the only way to do this. Read the instructions on how to install Flux after the break …

Installing Flux on iPhone and iPad involves downloading Xcode from the Mac App Store, for free. Xcode 7 lets anyone install apps locally to their iOS devices, which is how this whole process can work.

Next, download the open-source Flux iOS Xcode project from the Flux website. The app works on iPhones and iPads running iOS 9.

Double-click on the xcodeproj file to open Xcode with the file loaded. Connect your iPhone or iPad using a Lightning cable to your Mac. IMG_1349In the Devices menu (top-left of the Xcode window), you should see the name of your iOS device, such as Benjamin’s iPhone. Connecting the iOS device for the first time may require Xcode to do some initial setup, so wait patiently whilst it whirrs away if you don’t see your device name immediately.

Then, press the big Run button — it looks like a Play button from a video app. This builds the source code and packages into an app which will appear on your Home Screen. You now have the F.lux app installed on your iOS device!

The app includes normal night and day color temperature adjustments as well as settings for configuring when you wake up to optimize the transitions between states. Flux for iPhone and iPad even includes a dark mode which turns your device black and red, a stark change from the usual bright white UI of iOS 9.

The reason Flux isn’t allowed in the App Store is because it uses private APIs and requires constant background time. You should always be cautious when sideloading apps. If Flux ever causes problems, like iPhone battery drain, then simply uninstall the app to remove all the features and functionality.

Another major downside of side-loaded apps is that they cannot participate with the App Store automatic updates system. Flux will show a message inside the app if a new build is available but installing the update will require you to connect to Xcode again and perform the install dance again.

FTC: We use income earning auto affiliate links. More.

Check out 9to5Mac on YouTube for more Apple news:

You’re reading 9to5Mac — experts who break news about Apple and its surrounding ecosystem, day after day. Be sure to check out our homepage for all the latest news, and follow 9to5Mac on Twitter, Facebook, and LinkedIn to stay in the loop. Don’t know where to start? Check out our exclusive stories, reviews, how-tos, and subscribe to our YouTube channel

About the Author

Benjamin Mayo

Benjamin develops iOS apps professionally and covers Apple news and rumors for 9to5Mac. Listen to Benjamin, every week, on the Happy Hour podcast. Check out his personal blog. Message Benjamin over email or Twitter.