Unique Identifier for iOS devices [duplicate]

This question already has an answer here:

• I want unique identifier string which detect iPhone device (just like UDID)? 5 answers

I am looking for some id in iOS that uniquely identify every device. I know there is device token and vendor Identifier. But although, very rarely but these will change in some circumstances.

Does anyone know such an id for iOS device which do not change and will remain same.

Thanks