Square Enix announced on Thursday that it is developing a new Kingdom Hearts "experience" for smartphones tentatively codenamed "Project Xehanort." The project is slated for release this spring on iOS, Android, and Amazon. It will have in-app purchases. The project's tagline is "Why did he become the seeker of darkness?"
An official Japanese "Kingdom Hearts OOO OOO" Twitter account also opened on Thursday to provide information on Kingdom Hearts' new mobile service. (The "OOO OOO" characters represent six unrevealed Japanese characters.)
Square Enix had teased on Wednesday that the team working on Kingdom Hearts Union χ [Cross] will have an "unexpected announcement" on Thursday. Square Enix also teased that it has two more active teams besides the ones working on Kingdom Hearts III and Kingdom Hearts Union χ, and that one of the projects from these new teams will be revealed 'surprisingly soon."
Square Enix is currently holding a campaign where participants can guess the title of the game. Square Enix will give a prize to 10 winners who guess the name correctly.
Square Enix released the Kingdom Hearts III game in January 2019 in Japan and the West for the PlayStation 4 and Xbox One. The game had shipped more than 5 million copies worldwide, including digital sales, as of February 2019, and is the fastest-selling title in the history of the franchise.
Square Enix originally released the Kingdom Hearts χ ("chi", pronounced "key") PC browser game in 2013, and the game ended service in September 2016. The prequel game is set during the events of the Keyblade War. In the game, players create their own avatar and play as a keyblade wielder. The game inspired the Kingdom Hearts Unchained χ smartphone game, which Square Enix released in Japan in September 2015 and then released in North America in April 2016. It relaunched in April 2017 with the title Kingdom Hearts Union χ [Cross].
Update on January 31: The game's title is Kingdom Hearts Dark Road. Square Enix will reveal more details about the game around mid-February. Source: Kingdom Hearts Dark Road game's Twitter account
Sources: Project Xehanort website and Twitter account, Kingdom Hearts OOO OOO's Twitter account