emergency help about SystemInfo.deviceUniqueIdentifier on ios 7.0.4

I use SystemInfo.deviceUniqueIdentifier on my code.

My unity is 4.2.2 and 4.3
It works well on device with IOS 6.0 and prior


But on device with ios 7.0.4, In my iphone5s, iphone5, and ipad3

If I delete my app from phone, SystemInfo.deviceUniqueIdentifier will be different every time I delete my app and install again,


I need help, thanks a lot!

 

http://unity3d.com/unity/whats-new/unity-4.3

 

I got it. But it changes everytime after I delete my app. Why not unity stores it to keychain to keep it unchange?

 

Latest Unity versions use IDFV (id for vendors) as unique identifier, because Apple does not allow you to use IDFA for anything else than serving advertisements. IDFV retains its value until at least one application of specific vendors remains installed on device, once you remove last application of specific vendor this id gets reset.

 

So there is no way to identify the device than? Relying on that for limiting installs is horrible if the user reinstalls the app.

 

I'd be interested in knowing how Supercell identifies me on Boom Beach. I'm not logged in to Game Center or Facebook yet a fresh install of the game restores my last game state.

 

iCloud?

 

Well I signed out of iCloud and reinstalled the game and it still knows who I am.

 

Who knows , why i get different SystemInfo.deviceUniqueIdentifier on iOS every time after re-install app (Unity 5.2 + iOS 9)?

 

I believe that is just how it works unfortunately.