Yeah. you can use OpenUDID.
OpenUDID is a drop-in replacement for the deprecated uniqueIdentifier property of the UIDevice class on iOS (a.k.a. UDID) and otherwise is an industry-friendly equivalent for iOS and Android, and most recently Windows C# and Silverlight (see links above).
Here is the link:
You app will not be rejected because of OpenUDID. OpenUDID supports from version 5