Tom has an Apple TV and he just got a message on his YouTube app that the device isn't compatible anymore. Leo said there's a new update to the YouTube app that has broken the app on older Apple TVs. Leo says one possibility is to jailbreak it. If he needs to, he should check out Google's supported list of devices here. And he can always start the video on his YouTube app on the iPad or iPhone and then AirPlay it.
That's the way it is with computers -- updates just break stuff. It's the only way to move forward.