In my previous app,I was using the below mentioned code to generate unique deviceId for iOS devices.But the problem is that it will generate a new code everytime when the app is reinstalled.How can i do this properly?

```
-(NSString*)uniqueIDForDevice //new..
{
    NSString* uniqueIdentifier = nil;
    if( [UIDevice instancesRespondToSelector:@selector(identifierForVendor)] ) { // >=iOS 7
        uniqueIdentifier = [[[UIDevice currentDevice] identifierForVendor] UUIDString];
    }
    else
    { //<=iOS6, Use UDID of Device
        CFUUIDRef uuid = CFUUIDCreate(NULL);
        //uniqueIdentifier = ( NSString*)CFUUIDCreateString(NULL, uuid);- for non- ARC
        uniqueIdentifier = ( NSString*)CFBridgingRelease(CFUUIDCreateString(NULL, uuid));// for ARC
        CFRelease(uuid);
    }

    return uniqueIdentifier;
}

```