From the 1st, May 2013 Apple will reject the app which will use uniqueIdentifier. In my app i am using Paypal library and i found that libpaypalmpl.a is using <
Hence the third party library is using the uniqueIdentifier, you cannot do anything.
It's a popular library, so they will release an update soon, hope so. Wait till then, or remove the library and implement your own way for doing this.
Edit:
I read the documents of Paypal. Possibly there is one method that can have the uniqueIdentifier:
PayPalPaymentViewController *paymentViewController = [[PayPalPaymentViewController alloc] initWithClientId:@"YOUR_CLIENT_ID" receiverEmail:@"YOUR_PAYPAL_EMAIL_ADDRESS" payerId:aPayerId payment:payment delegate:self];
In which the payerId can have the value of your device's unique Id. If you added like so: change it to either an emailId or nil.
Please check Paypal SDK Documentation