Next mythic skin? (Answer from rioter pls)

I was wondering if their is gonna be a next mythic skin (a.k.a hextech exclusive skin) in the following patch notes hextech annie released at patch 6.5 and soulstealer vayne at 6.13. Is their is gonna be a new one at 6.21? Rioter pls tell me the plans :D I already have soulstealer vayne,only need annie but I'm scared that their could be a potential release for one of my loved main champs :D (katarina and miss fortune) even though they both got recently new skins, you can't always trust a company x)