To update the Apple TV, open the Settings app. Then select System > Software Update > Update Software > Download and Install.
Why this matters: This is a pretty huge update, and both key features were sorely needed. We complained the loudest about the lack of Remote app support, since using the software keyboard on the iPhone to enter usernames, passwords and search terms is about a zillion times easier than hunting-and-pecking a letter at a time with the Siri Remote (or even with the old remote, to be honest). The lack of Siri support for Apple Music on the Apple TV was confusing too, since it works so well on iOS. Apple had promised to get it working in early 2016, so we’re glad the company beat its own estimate. Both of these additions make the Apple TV easier to recommend as a holiday gift.