According to ain the official forum:
"This will certainly not be the final update for the game. Atari will continue to support the game with regular releases of DLC.
"We do not have any further details on the content and timing at this time, but I can confirm that we will continue to evolve the gameplay and the online experience of Test Drive Unlimited 2."
TheExploration DLC will come with 20 new events, new event types, new cars, new outfits and a new help channel.