Tetsuya Nomura, famed for directing the Kingdom Hearts series and giving more outlandish titles as the series progressed, recently spoke about the development details of the newest remix. Kingdom Hearts II.8 was announced at Tokyo Game Show and is comprised of Kingdom Hearts Dream Drop Distance, Kingdom Hearts X Back Cover, and Kingdom Hearts 0.2 Birth by Sleep Fragmentary Passage. Nomura gave an interview, translated by Siliconera via Hachima, in which he stated that there is no timeframe for the development status on KH2.8. He described how the three games are not just simple HD ports, as Dream Drop Distance is going from the two screen setup of the Nintendo 3DS to a single screen home console. Additionally X Back Cover is a movie, reflecting the inclusion of 358/2 Days and RE: Coded as simple cutscene movies.

Lastly we have KH0.2 which is a story revolving around Aqua's time in the realm of darkness, taking place after the Birth by Sleep Final Mix's secret trailer. Nomura talked about that particular scene last year (via KH13),

By the way, the indication for Birth By Sleep -Volume 2- is still there. It shows the existence of Aqua's story in the Realm of Darkness. It means that she didn't just wander about in the Darkness for ten years, but that she passed through many experiences. However, it is a "Fragmentary Passage", as the same suggests-- that story was severed and wasn't told. I hope I can tell it when given the opportunity.