Just a quick observation. I find that the NSNotification.Name NEVPNStatusDidChange is not visible when the Swift Compiler setting: C++ and Objective-C Interoperability is set to C++/Objective-C++. Simply switching between C/Objective-C and C++/Objective-C++, a successfully building app is no longer able to build with error: Type 'NSNotification.Name?' has no member 'NEVPNStatusDidChange'. The Swift code being used is: NotificationCenter.default.addObserver(self, selector: #selector(self.updateNetworkStatus(_:)), name: .NEVPNStatusDidChange, object: nil)