Due to various issues, the game has been delayed to an unknown date in 2019.
Bushiroad has announced it plans to delay the release of its mobile game, Cardfight!! Vanguard ZERO.
The cited reasons are feedback from testing and demonstrations at major events.
Cited issues are game play problems, visuals not being up to snuff, desires to make the My Room system better, and near as I can tell, attempt to improve Cardfighting.