The Ys series is quite old honestly, so old in fact that Ys IV was made in two versions, Ys IV: Mask of the Sun which was released on the Super Nintendo in 1993 and Ys IV: The Dawn of Ys the same year for the PC. Despite the age however, Ys IV is going to be totally remade for the PlayStation Vita by Falcom.
As you can see in the leaked screenshot above the game is going to be extensively remade. The official name for this new remake is Ys IV: Woodland of Celceta. Despite the leaked screenshot above, not much is currently known about the title, including which version of Ys IV will be remade into this title.