Our iOS application is for specific users. So, we used **device unique identifier** for user identification. This approach works fine till iOS 6, because we are getting the **same value** every time.

```
NSString *strUniqueIdentifier = [[UIDevice currentDevice] uniqueIdentifier];

```

In iOS 7, the above method is returning **different values** and we are getting issues in user identification. iOS 7 provides the following **alternate**.

```
NSUUID *oNSUUID = [[UIDevice currentDevice] identifierForVendor];
[strApplicationUUID setString:[oNSUUID UUIDString]];

```

We replaced `uniqueIdentifier` with `identifierForVendor`, and created an Ad-hoc build. We then installed the build on both iOS 7 and iOS 6 devices. So far in iOS 7, we are getting the **same value** every time, but iOS 6 gives **different values** every time we delete and reinstall the app.