According to the letter I received, it is a change from the originally scheduled September dates to a different time in October:
“Due to a change in the course instructors, we have had to shift the dates to October 5-13, 2018. We recognize that this date change is coming to you on short notice, and sincerely apologize for the inconvenience this may cause. We hope that you will still be able to participate in this offering, and understand if that is not possible.”
Hope this is helpful.