Spotted on the UK WDW site these are most likely the dates for Mickey's Not So Scary Halloween Party.
August 17, 24, 28, and 31
September 3, 7, 9, 11, 14, 16, 18, 21, 23, 25, 28, 30
October 2, 4, 5 8, 9, 11, 12, 14, 16, 18, 19, 21, 23, 25, 28, 30, 31
These have not been confirmed in the US yet but will most likely be the dates to plan for.