If you’ve installed iOS 9 public beta that Apple made earlier this month, you will be happy to know that it is still possible for you to install iOS 9 beta 4 on your device without needing to be a registered developer…
How to update iOS 9 public beta to developer beta
Step 1: Open Settings → General → Profile
Step 2: Tap on the iOS 9 Beta Software Profile
Step 3: Tap Delete Profile → Delete
Step 4: Reboot your device
Step 5: Open Settings → General → Software Update to check for the latest iOS 9 developer beta
Step 6: Tap Download and Install to begin the iOS 9 beta 4 installation
By using this method, it’s possible to upgrade to the latest developer beta in a legitimate manner without actually needing to be a developer. Keep in mind that this is beta software, so your mileage may vary. I did test this personally, and it worked fine for me. Be sure to watch the video to see it in each step.
