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Apple shuts down iPhone and iPad screen brightness adjusting app Flux


Yesterday we shared that the popular automatic screen brightness adjusting app Flux had found a way to make it from the Mac to iPhones and iPads on iOS 9. This afternoon the developers behind Flux announced that the app will no longer be available on iOS at the request of Apple. In a blog post sharing the development, the developers behind the app said that Apple contacted them to say that the app violated Apple’s Developer Program Agreement. While the app was unofficially supported on iOS 9 as a sideloaded app and not an official App Store app, Flux did use Xcode signing to work properly on iPhones and iPads.

Flux on iPhones and iPads with iOS 9 was originally made possible due to limitations being lifted around Xcode, which is available for anyone to download from the Mac App Store. Flux no longer being available is the first major instance of signing apps with Xcode and sideloading them unofficially without the App Store going sour.

This is likely due to the popularity that the automatic screen brightness utility enjoyed during its short run on iOS. In the blog post, Flux’s developers share that the Flux iOS page was visited 176,000 times in just one day, in part thanks to being featured on this website yesterday. Flux on the desktop, they say, has been downloaded over 15 million times.

f.lux cannot ship an App using the Documented APIs, because the changes we make are not allowed. In the last 5 years, we have had numerous conversations with Apple about our product and what would be required to make it work with iOS.

We respect Apple’s products enormously, and we urge Apple to allow work like ours to continue through Documented APIs.

You can read the full blog post explaining the situation here.

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  1. prentom87 - 7 years ago

    Does it still work for those that already installed it? I have a copy that I haven’t installed, and was planning to do so today.

    • pointum - 7 years ago

      Apple is not revoking the certificate the binary is signed with. It will continue to work unless the developer had intentionally added an expiration mechanism to the beta.

  2. echristoperj - 7 years ago

    My copy still works. :)

    • methodicjon - 7 years ago

      Help me Ronda. Help help me Ronda.

      Code plz?

  3. rogifan - 7 years ago

    Isn’t this because it was using private APIs? Shouldn’t be surprising at all that Apple would shut down an app not available on the App Store. Last time I checked Apple has never supported sideloading apps on iOS device even if it is technically possible via Xcode.

    • pointum - 7 years ago

      Apple can’t stop anyone from using private API in their code or projects, but they can revoke developer certificate so that you won’t be able to distribute the app. Flux developers could release full source code so anyone could build it from scratch. Or they could distribute the beta binary without developer signature, but then only other developers would be able to side load it with their own certificate.

  4. jb510 - 7 years ago

    There are two reason I keep my iPhone’s Jailbroken. #1 F.lux and #2 SwipeSelect. That’s it. Sure I also install flipcontrolcenter, wicarrier and killall, but I could live without those. SwipeSelect and F.lux no.. and both use “undocumented” APIs that violate Apple’s rules… so staying jailbroken and only buying a new phone when a jailbreak is available continues.

  5. Toro Volt (@torovolt) - 7 years ago

    This BS is one of the reasons why I have an Android phone.
    There are dozens of free Android apps that do this helpful dimming minus blue screen.
    Still have an iPad mini thought, so i can get the best of both worlds. :)
    This feature should have been part of Core iOS and Android long ago.

  6. Richard Millet - 7 years ago

    Everyone please read the blog post from the f.lux developers. The link is at the bottom of this 9to5Mac article. Use the link on the blog post to send Apple a request to open up the APIs needed for f.lux to become available on iOS devices.

  7. bennynihon - 7 years ago

    bummer. this is one of the few (if not only) reasons I still want to be able to jailbreak my iPhone. Considering Apple has stressed its stance behind health and fitness starting with iOS 8, I find it peculiar that they don’t offer this functionality baked into iOS. We could all stand to benefit a bit from having a little less light from the blue end of the spectrum and the harmful effects it has on suppressing melatonin and our sleep.

  8. Olivier Pilon (@froli13) - 7 years ago

    I still have the file on my computer if some of you are interested, just hit me on twitter @froli13 and I’ll send you a dropbox link or something like that! :)

  9. Leif Paul Ashley - 7 years ago

    Saw that coming.

  10. jansoucek - 7 years ago

    f.lux is the worst kind of snake oil… stupid people not realizing how physics of light work willingly destroying white balance on their beautifully calibrated mac displays… good riddance!

    • bipedxing - 7 years ago

      You can disable f.lux temporarily or permanently on a per-app basis if you’re doing work that requires a proper white balance. Reading twitter at 2am does not. You can adjust the color temp on a other displays, Wanting that feature on other displays doesn’t really seem stupid to me.

    • morganonscience - 7 years ago

      Yes, these “Stupid People” are following the “Stupid Science” published in places like the Proceedings of The National Academy of Sciences:

    • I was rubbing my eyes 3 weeks after Yosemite, then iOS 9 came out. Friend mentioned “You need to get flux”. I’d hardly consider this snake oil. I don’t rub my eyes anymore after installing it, and as others stated you can setup rules about what does and doesn’t get effected by this. White/Blueish light is brutal to anyone staring at a screen for 6-10 hours a day. Dark themes aside, this fills the gap for eye strain and fatigue. Ultimately, depends what you do with a computer throughout the day but the increase in vivid colors had a horrible side effect.

    • Vyazhan - 7 years ago

      Of course, accusing people of being stupid instead of giving them a proof for your claim makes you stand as the bigger fool however :)

  11. Simon-Lennert Raesch - 7 years ago

    There is some information missing from this article.

    First, and most interesting for everyone interested in acquiring the app: It is still available on github, here, have a deep link:

    Second, and most important for anyone interested in the reasons for this to happen: f.lux is distributed precompiled, the surrounding app loads any pre-compiled binary onto your phone. This is bad. If I was to provide you a fake “mirror” I could easily add my own harmful code to this app. If the f.lux developers were to open source their code Apple would probably be just fine with it, as a lot of other open source projects using private APIs on github prove.

    I strongly believe this second part should be added to the article for clarification.


Avatar for Zac Hall Zac Hall

Zac covers Apple news for 9to5Mac and hosts the 9to5Mac Happy Hour and 9to5Mac Watch Time podcasts.