HBO Now waves goodbye to older Apple TVs
Third-gen Apple TVs launched eight years ago, and HBO thinks it's time for an upgrade. However, people don't buy set boxes as frequently as other gadgets (mobile phones, for example), and many of them are still using these older Apple TV models. The timing is not perfect either - there are rumors of a tvOS hardware refresh later this year, so don't rush to the stores yet.
HBO Go will have to go, too - it will be available for a couple more months and then follow HBO Now's fate. The upcoming HBO Max streaming service will also be supported on the 4th-gen and later Apple TVs. All in all, everything points toward an upgrade, but if new hardware is in the pipeline, a little patience can be a wiser choice.