According to a report by Austrian news agency APA

Says that a special summit will be held in Brussels on 17-18 November to secure an agreement on the UK's withdrawal from the EU. There's no official source cited by the news agency here so it's a bit iffy at the moment if you ask me, particularly when the October summit still to come.

But if they've already set a firm date for this, it means that the October summit isn't going to be discussing Brexit details much - if at all.