The Xbox One SmartGlass companion app is now available for Windows computers, Windows Phones, iOS devices, and Android devices.
You also get an early look at the new Xbox One Challenges, similar to Achievements (but not replacing them), they’re time specific challenges for you to complete for bragging rights. Also the new Friend/Follower system has been activated on Xbox Smartglass so go ahead and begin to sort your friends list, add gamertags to a list of favorites, and begin following your favorite gamers. With the launch of Xbox One the friends list cap is increased to 1000 gamertags. You can follow people and if they follow back, you become friends.
iOS Devices (iPhone/iPad): https://itunes.apple.com/us/app/id736179781?mt=8