From the trailer we see, aside from the new party member a new Doctor Character too, a new explorable Hub with a place that has a pool table, darts and other bar games, enhaned dungeons, Joker now has a Grappling Hook, January being playable, the team sending selfies of moments in the story in the Chat and new attacks for Futaba and the Benched party members.
Atlus USA just confirmed it will coming out on 2020 on the west.