Actually, deactivating and then activating the free version fixes MOST of the problems. I can create a new event (also edit and delete it), and the new event appears in my event calendar/event list. But the actual event page still gives a “404 Page Not Found” error.
Good deal, and depending on your host, you may need to clear CDN or server side caching (same if you use a caching plugin). That would only be needed if you visited a page that generated a 404, did the deactivate/reactivate move, then revisited the page without refreshing.