This took me so long to find on the RFL site thought I would post it here too. Hope it saves somebody else some time:
"Details of the Super 8s fixtures for Kingstone Press League 1 and the League 1 Shield will be confirmed on the morning of Wednesday July 19 and fixtures will begin on Sunday July 30.
Details for the Betfred Super League, Qualifiers and Kingstone Press Championship Shield will be published on Wednesday July 26: this will allow all clubs to feed in details of their stadium availability once the regular season has been completed, and give broadcasters the opportunity to select televised fixtures for the early rounds of Super 8s. The Super 8s begin on Thursday August 3."