Check out the articles here, and here detailing the specifics of the reveals. The new mode was announced at PAX East 2013 along side a new playable character class called, Krieg and a fourth coming DLC named Tiny Tina's Assault on Dragon Keep. The new mode was released alongside a level cap increase by eleven. The mode is available to anyone who has beaten True Vault Hunter Mode and reached level 50 and has enemies scaled to the highest level in your party. On April 2nd, 2013 Gearbox released a new mode called Ultimate Vault Hunter Mode as a free update to all players.
