The offer will not be cross platform though, so if you own the game on Xbox 360 you will only be able to upgrade to the Xbox One version and not the Playstation 4 version. Gamers will be pleased to know that any progress that they make on the Last-Gen version will carry over onto the New-Gen version, as well as the DLC from the Season Pass should you purchase it. Not only that but it will also carry backwards if you decide to switch back to the Last-Gen version.
You have plenty of time to make the leap and upgrade as the offer is valid until January 2015.
Destiny is due for release on 9th September on Xbox 360 and One, and Playstation 3 and 4.