As far as I know, you need to complete Korg's onesie event for this to unlock. The event is available in Bareshade on Sundays as a Halloween event (I haven't tried it, but that's what it says on the game's Event log)
I vaguely remember doing this though. Any way of activating it in case i haven't?
My only advise is to play again the halloween event in Bareshade in hopes of triggering the condition for this new updatde