Zanki Zero: Last Beginning 21:9 (2560x1080) FIX REQUEST

[igork2]

How do i config this game to be on ultrawide? i have an 21:9 2560x1080 monitor and i set the game in this resolution on ZankiZeroSetting, but there is still black letters on the sides.
I saw an video on yt of some guy running at 4k ultrawide, so i think this should support 2560x1080 right? if not, can someone help me? This game seems awesome but playing on 16:9 kills the game for me.
Thank you.