I am going to make beta test for my new app and tried to find a simple way for my customers to get their UDIDs. Well, there are some apps on AppStore to get UDID. But none of them really work! They got completely different numbers than what I got from iTune! Can those UDIDs used to for beta test? I really doubt it.
"They got completely different numbers than what I got from iTunes! Can those UDIDs used to for beta test?" No they don't.
They use the [UIDevice currentDevice].identifierForVendor.UUIDString witch is different from the device's UDID. And change each time you reinstall the application.
You should use TestFlight witch is fully automatic or some simple page where the user can get it and send it to you, or make your own solution via PHP, read the official documentation about OTA configuration