I saw somewhere on Halford's forum that there's going to be a special guest at this show and that it's being recorded. The obvious guess would be K.K., but maybe it'll be someone like Les Binks!
Edit: Screw phones, I didn't mean to put a thumbs down on this post.
Brocas Helm/Hatchet/Exmortus/Midnight Chaser 11/22
High on Fire/Kvelertak 12/12
Exodus/Nails/Hellfire (???) 12/20
Neurosis/Bl'ast!/YOB (???) 12/29