As long as you have iOS 5 or later, you should be able to install it. To add to what Daniel said, once you get that error, your UDID (an identifier specific to your iPhone) will get sent via TestFlight to me. I will add your UDID to the distribution profile so that you will be able to access it (you should get a notification at this time). I hope you enjoy it, and since we are very actively developing it, any feedback would be useful for us. We encourage you to send an email to [email protected].