While certainly not required for gameplay, the new Assassin’s Creed IV companion app offers simple mapping and game-tracking options for the game. The app is free to download on iTunes and Google Play.
Essentially a more fully-featured version of the mapping and game-tracking options already found in Assassin’s Creed 4, the game’s newly-released companion app is far from mandatory. Still, it’s available as a free download on iTunes and Google Play, so it’s hard to complain about what might have been.