Apple has today released a new update for Apple TV 3, listed as firmware 7.2.1 (iOS 8.4.1) build 12H523. The update is available to download to Apple TVs that are connected to the internet, whether that be via ethernet or WiFi.
The next generation Apple TV may be going on sale this coming Monday, but there is still plenty of life in the existing model with three new channels being added to its content lineup.