Recently a method was discovered that could get the popular screen brightness adjusting app, f.lux, onto an iPhone or iPad running iOS 9 without jailbreaking the device.

f.lux had quickly grown in popularity as a Cydia tweak on jailbroken devices, so to see the app become available for non-jailbroken handsets was immediately popular. Indeed, the developers behind the app confirmed a massive spike in popularity for the app after it was promoted across the internet.However, while that popularity was good for the app, Apple didn’t agree, and has effectively shut down the app.

f.lux automatically adjusts the brightness of your device depending on the time of day. So it’s warmer and easier on the eyes at night. You’d be amazed to realize how relaxed your eyes feel after installing this tweak, especially if you tend to use your iPhone just before going to bed.

By way of a request from the Cupertino-based company, the developers have removed f.lux from the site where it was previously available, and it is no longer available on iOS. Apple says that the app violated the Developer Program Agreement, and used that as their basis for shutting down the app. f.lux wasn’t an official app available through the iOS App Store, but it still did use Xcode signing to make it possible for the app to work on iOS 9-equipped devices.

Apple has contacted us to say that the f.lux for iOS download (previously available on this page) is in violation of the Developer Program Agreement, so this method of install is no longer available.

We understood that the new Xcode signing was designed to allow such use, but Apple has indicated that this should not continue.

Apple recently lifted limitations around Xcode as it made it possible for anyone to download it from the Mac App Store. As such, the developers believed that their app, even being side-loaded, would not go against Apple’s own rules and regulations. It’s possible that f.lux’s aforementioned sudden popularity is one of the reasons it was notably shut down by Apple.

You can read up on the developer’s stance on the move from Apple right here.