Kingdom Hearts 3D: Dream Drop Distance will provide some details on Kingdom Hearts III, according to Famitsu's recent Square Enix feature. There will be a hidden movie, though whether it will contain these details was not stated directly. Tetsuya Nomura said to the magazine that Sora will still be the protagonist in games after Kingdom Hearts III, but said game will be the last appearance of Xehanort as the main antagonist.
As for Kingdom Hearts 3D itself, Nomura says it is between 40% and 50% complete. The story will reportedly be mysterious and hard to follow, involving Sora's secret data. Nomura also stated that Traverse Town will have two certain elements to it, but the specifics were obscured in the magazine feature. These may be new areas to explore, but nothing is certain for now. It will also be possible to climb up onto rooftops.
Kingdom Hearts 3D: Dream Drop Distance is an upcoming 3DS game which according to Nomura, will have a story on par with the main series. There is no known release date for the game in any part of the world. Kingdom Hearts III has long been spoken about, but development has yet to begin on it. It is not known when the game will come out, or even what platform(s) it will be on.