Firewatch has received a new update which adds a new open world mode to the game. The Open World mode has no objectives so you are free to explore. It also features a day/night cycle. The Open World mode is unlocked after you complete the main game.
The update on PlayStation 4 also adds graphical updates for players with a PlayStation Pro such as support for 4K resolution and better visuals on 1080p TVs.
The update is already out on PlayStation 4 and Xbox One but isn't coming till tomorrow for the Steam version of the game.