If you install the iOS 15.1 beta without registering your UDID, your device will be deactivated with an error like this:
This device is not registered as part of the iPhone Developer Program. If you are a member of the iPhone Developer Program, please register your device in the iPhone Developer Program Portal.
As Apple warns, installing beta software on your device without registration "could put your device in an unusable state and necessitate an out of warranty repair." By registering your device, you'll be able to safely use any beta firmware.
We'll provide you with certificate and provisioning files that can be used with iOS App Signer or Xcode to sideload apps onto your device. This requires the Plus, Premium, or Ultimate package and a Mac.
In the event of a wait list due to high demand or Apple downtime, we will register devices with the Premium and Ultimate packages first.
If your device is replaced due to theft or exchanged under an insurance program within 6 months of purchase, we'll register your new device. This is a free service for those who purchased the Premium and Ultimate packages.
Apple can revoke certificates at any time and for any reason. While the Plus package is only eligible for replacement in the first 90 days, the Premium and Ultimate packages remains eligible for replacement for an entire year. Simply look up your order and download a replacement certificate. Completely free and automatic.
Sign and sideload apps onto your device in the cloud without a Mac. This is the easiest way to sign apps and requires the Ultimate package.
Follow these instructions to find your UDID.
Enter your UDID on the homepage and click "Check" to see the status of your registration.
We send confirmation emails instantly to the email address associated with your PayPal account. Be sure to check your spam folder.
Our service doesn't provide you with direct access to a developer account or beta downloads. All we do is register your device with one of our own developer accounts.
Your registration will last for all betas of iOS 15.1.
After you register your device's UDID, we send you an email with a link to the instructions.
Follow these instructions to enter recovery mode, then restore in iTunes.