We published the ACCU 2020 schedule just some days ago. There is the usual disclaimer that the schedule is subject to change without notice till the end of the conference. This is intended to mean just amendments to the sessions, quickies, side events, or social events, as the keynotes are normally fixed points.
This year we have such an unusual situation, again. Which means we need to swap two of the keynotes this year too: Kevlins’s Saturday closing keynote has become Thursday’s opening keynote; and Sean’s Thursday opening keynote has become Saturday’s closing keynote. Given that constraints sometimes change - what never happens in real life software projects as we all know, - this was unfortunately The Right Thing To Do™ even though it is a change to the keynotes post publication of the schedule.