Here is the list of release dates:
Booster Pack+ and Booster Pack (Free Version) – February 21, 2017
Obtain powerful items that give you an advantage in battle and make them more exhilarating with the “Booster Pack+” and “Booster Pack (Free Version).” One of the items is an suit that makes you invincible for 30 minutes. (It also boosts your fishing skills. After use, it cannot be used again for 24 hours.)
Episode: Gladiolus – March 28, 2017
An original episode that unfolds from the perspective of Gladio, who was not playable in the main story of Final Fantasy XV. Enjoy fresh controls with Gladio-like action different from Noctis. Additionally, Final Fantasy series familiar character Gilgamesh will also appear.
Episode: Prompto – June 2017
No new details were shared.
View screenshots from the “Episode Gladiolus” add-on at the gallery.