A couple of days ago the Jump Festa took place in Japan (which is an annual exposition showing new anime, manga and also games). During the event a new trailer has been revealed of Kingdom Hearts HD 2.5 ReMIX showing in-game footage of the 3 games (Kingdom Hearts II, Kingdom Hearts: Birth By Sleep and Kingdom Hearts Re:coded (cinematics only) that are included in this HD version.
Kingdom Hearts HD 2.5 ReMIX is stated for a release somewhere next year.