Deprecated Xcode issues

im getting errors and warnings with the following code:

1. Warning undeclared selector uniqueIdentifier at the first if statement;
2. Error Property uniqueIdentifier not found on object of type UIDevice
3. Error Cast of C pointer type CFStringRef

// Get the users Device Model, Display Name, Unique ID, Token & Version Number

UIDevice *dev = [UIDevice currentDevice]; NSString *deviceUuid; if ([dev respondsToSelector:@selector(uniqueIdentifier)]) // Warning #1 deviceUuid = dev.uniqueIdentifier; // Error #1 else { NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults]; id uuid = [defaults objectForKey:@"deviceUuid"]; if (uuid) deviceUuid = (NSString *)uuid; else { CFStringRef cfUuid = CFUUIDCreateString(NULL, CFUUIDCreate(NULL)); deviceUuid = (NSString *)cfUuid; // Error #2 CFRelease(cfUuid); [defaults setObject:deviceUuid forKey:@"deviceUuid"]; } }