With iOS 16, Apple is making some changes to prevent attackers from sideloading malicious apps on the device – which includes de addition of a new Developer Mode. However, these changes caused a bug in the first beta of iOS 16 that also requires this mode for TestFlight apps.

Update (June 22, 2022): Apple has fixed this bug with iOS 16 beta 2. Users can now run TestFlight apps without having to enable Developer Mode. You can read the original article below.

When users try to run a TestFlight app that you have just installed or updated, the system warns them that that app now requires Developer Mode enabled. A message reads: “Until Developer Mode has been enabled this app will not be available for use.” But what is Developer Mode and how does it affect the TestFlight apps?

As explained by Apple in a session at WWDC 2022, some of the features used by developers to allow them to sideload their apps during the development process now come turned off by default in iOS 16. According to the company, this is a security measure to prevent malicious apps from using developer tools for targeted attacks.

In the first beta of iOS 16, this new feature also affected TestFlight and enterprise apps. Luckily, Apple has confirmed that these apps will not require Developer Mode to run since they already have a valid certificate, so the alert is just a bug that will be fixed in a future update.

How to enable Developer Mode in iOS 16

If you’re having trouble running TestFlight or enterprise apps on iOS 16, you can enable Developer Mode by going to Settings > Privacy & Security > Developer Mode. Apple says the option is available to all users running iOS beta, but once iOS 16 is released to the public, it will require pairing the iPhone with Xcode first.

Interesting to see this on an app I installed via TestFlight.

Looks like newly installed or updated apps via TestFlight will show it if you don’t have Developer Mode enabled.

Not sure if it’s a bug for feature. pic.twitter.com/qvVa5thvIl

— Daniel Hipskind (@DanielHipskind_) June 7, 2022

Of course, if you’re not a developer, we suggest that you keep this option turned off to ensure the security and integrity of your device.

iOS 16 is currently available as beta software for developers via the Apple Developer website. A public beta will be released next month, while the official release is expected this fall.

More about iOS 16

  • Some iOS 16 features require an iPhone XS or newer; here they are
  • iOS 16 expands support for game controllers, now works with Nintendo’s Joy-Cons and Pro Controller
  • iOS 16 asks user permission to copy and paste between apps
  • iOS 16 brings new dynamic wallpaper ‘collections’ – Here’s a closer look
  • iOS 16 enables web push notifications and extension syncing with Safari update