October 19 & 20.  
No word on when the tickets will be on sale.  That's the reason I keep checking this forum.    
 

The lack of any announcement this late has me disheartened.  It is difficult for gamers to come from out-of-state with no advance notice.  If Arkham Nights is October 13-14, it is less than a month away, making arrangements will be very difficult. 
Heck, I can tell you the dates of GenCon 2020 (July 30-Aug 2) and Origins 2018 (June 13-17) even though those events might not have any content yet, I still know when they will be held, so I can put in leave requests, arrange transportation, and finding lodging (if not through con site).