Destiny: Rise of Iron will increase it’s light level cap to 400 when the new raid launches, from the previously announced light level cap of 385.
When Destiny: Rise of Iron is released, the new light level cap will be raised to level 385. When the new raid is released post-launch, the new light level cap will be raised to 400 with the introduction of new gear, such as weapons and armor. The character level will remain unchanged at level 40, as it was with the release of Destiny: The Taken King last year.
It was announced this year that Destiny: Rise of Iron will be exclusive to the Xbox One and Playstation 4. The previous generation consoles such as the Playstation 3 and Xbox 360 will have their life-cycle end with Destiny: The Taken King, which was released last year.
Destiny: Rise of Iron will be available on September 20th, 2016.
Source: Gameinformer
