Iron Banner, any Crucible, and Forge. Exotic engrams will decrypt above your light level also. Legendary engrams cap out at different levels ending at 385 but exotics go to 400. Make sure you equip your highest leveled gear before you decrypt engrams in order to get the most out of them. I haven't don't the ROI raid, everyone I used to play with quit destiny, but all of my characters are level 400. I started ROI at 335 on all characters and completed 400 on all very quickly. When you get your first character to 400 just decrypt all exotics with that one to get 400 out of them then transfer to your other two. Same for Banner and any other rewarded game play, use your first 400 to feed your others. Edit: If you're playing Banner, regular Crucible, or any other rewarded gameplay make sure you have your highest leveled gear equipped. Even if you switch it just before the game ends. Your reward is based on your current equipped items.