You can actually do this from the ST cloud. If you hub goes offline, the ST cloud still knows about it. So, you can notify yourself from ST if your hub is offline. The problem with doing this on your home network is that if you’re offline you can’t send yourself the notification. And if you fail over to another means of getting online, you’re now back-online so why would it send the notification. If you are using some-type of redundant backup internet, that system should have a way of notifying you that it’s gone to backup mode.