Accroding to Square Enix the next Final Fantasy smartphone game the Final Fantasy Legends II release on November 10, 2016 in Japan.
The pre-registration season already closed and the game will be available in the AppStore and the Google Play from 0:01 but Square Enix going to starts immediately a service maintenance and you can play with it from 15:00 (local Japan time).

The pre-registration season was alive for 8 days and during this time 103 094 people registered for the game.