Yes, it should be in the `dealloc` method:
```Objective-C
#if !(OS_OBJECT_USE_OBJC)
- (void)dealloc {
    if (self.queue) {
        dispatch_release(self.queue);
    }
}
#endif
```

On iOS5 ARC doesn't manage GCD objects for you so if the deployment target is set to iOS5 you have to use the 'old way'. iOS6 added ARC-support for GCD objects!