Contrary to what the name suggests, it’s a brand new game, not a re-release.
After a short countdown, Atlus today announced Shin Megami Tensei IV: FINAL, a new game in the Shin Megami Tensei universe that is set in the same universe as the excellent Shin Megami Tensei IV, which released on the Nintendo 3DS back in 2013. Not a whole lot is known about the game, except for its general setting (it seems to be directly related to Shin Megami Tensei IV somehow, and it seems like its central theme is ‘Godslayer’), although we do know that we will learn more about the game next week.
Shin Megami Tensei IV FINAL is the first game in the franchise to feature a direct connection to another game in the series since Shin Megami Tensei II, which was a direct sequel to the original Shin Megami Tensei. The name implies it is a direct sequel, though of course, nothing is stopping it from being a prequel or even an alternate universe take on the same narrative.
Shin Megami Tensei IV FINAL will launch on the Nintendo 3DS exclusively, on February 10 2016 in Japan. A western release date has not yet been confirmed.