Short answers, pulled from the story.
Final Fantasy XV: Pocket Edition was released for Android and iOS devices on the 8th of February 2018. This release date was one day earlier than the initially announced schedule for the mobile version.
Hajime Tabata served as co-producer for Final Fantasy XV: Pocket Edition alongside Kosei Ito. Tabata was the director of the original Final Fantasy XV game and used an iPhone daily during the development process.
The development team rebuilt the entire game using the Unity engine for Final Fantasy XV: Pocket Edition. This replaced the in-house Luminous Engine that powered the original console version to accommodate hardware limitations.
Final Fantasy XV: Pocket Edition reached three million downloads within its first month after release. This mobile adventure transformed the original console-bound epic into a ten-chapter experience.
The Nintendo Switch version of Final Fantasy XV: Pocket Edition was released on September 13. This release followed the PlayStation 4 and Xbox One versions which arrived on September 7.