The change is due to the annual Hull Fair taking place that weekend on Walton Street next to the KC Stadium.
Following the change of date, the match has now been downgraded to a Category B fixture, meaning that admission prices will be less than was first planned.
The home game against Milton Keynes Dons has also been put back 24 hours. It will be played on Wednesday 20th October at 7:45pm.
City's game against Bradford was also recently moved. It's to be held on Tuesday 31st August (kick-off 7:45pm).