Apple seeded iOS 8 beta immediately after the WWDC Keynote yesterday.
Ideally, beta versions can be installed on iOS devices whose UDIDs are registered in the iOS Dev Center.
However, a number of users are reporting that they’re able to update to iOS 8 without registering the UDID of their iOS device for which you need a developer account.
It looks like the trick is to update the device with iOS 8 firmware by holding the Option key on Mac or Shift key in Windows, and clicking on the Check for Update button. The is similar to the steps mentioned in our how to install iOS 8 beta guide minus the steps mentioned under the provisioning section.
Cody has also confirmed that it works and has posted a video on his YouTube channel to show how to install iOS 8 beta without UDID:
You will still need to download the appropriate iOS 8 beta firmware file, which can be easily found online. If you plan to give it a try, I would strongly recommend you to read the article on some of the risks involved in installing iOS 8 beta. Also note that some readers are reporting that they’re getting a notification prompting them to activate their device, which would need a developer account, so proceed with caution.
If you still decide to upgrade, then remember to take a backup of your device, so you can always revert back.
Let me know how it goes in the comments below.