Some members of Game Freak, the developer of all main series Pokémon games, reportedly had a recent interview with Japanese magazine Famitsu. Information from this interview appears to have leaked before the issue of Famitsu with released, however.
Information from the interview was recently posted on Game’s Talk and later translated into English on NeoGAF by user sinonobu. One thing that is revealed from this information is that Ultra Sun and Ultra Moon won’t be sequels to Sun and Moon, but rather tell the same basic story but with “different divergence.” The inclusion of the Ultra Recon Squad is listed as one of the things that will bring drastic change to the story and it is also stated that these games will be much more different from Sun and Moon than Platinum was from Diamond and Pearl, or Emerald was from Ruby and Sapphire. In fact, the script for Ultra Sun and Ultra Moon is reportedly twice as long as the script from Sun and Moon, so expect more than just minor changes.
The leaked information also states that there will be more post-game content for players who defeat the Elite Four and that capturing and raising Pokémon will somehow be easier in these games than in Sun and Moon. It is also stated that the player will be able to use Ultra Wormholes to visit different dimensions and that Legendary Pokémon, such as Mewtwo, can be found in these new dimensions.
Pokémon Ultra Sun and Ultra Moon will be released on November 17 for the 3DS.