The official GTR website has posted a patch for their game.
"With the official European release of "GTR - FIA GT Racing Game" on the 11th of March, all fans of the Award-winning motor sport simulation can finally compete on an international level. Everyone who is running the German box-version must update their games to 1.3, as all public servers will be switched to the new version. The update 1.3 offers improved multiplayer stability and performance, as well as graphical improvements; new setups for all the cars that came with the "Proximus 24H of Spa" Add-On; and two new race classes with the Cup 400 and Cup 300. So be prepared for thrilling man to man races on hot asphalt in the sun of Monza or during heavy rain in the night of Spa-Franchorchamps."