Hi Peter,
I’m sorry you were getting 404 errors after updating! I just took a look at your site, and the events appear to be showing up correctly now. Were you able to get this resolved?
If you were not able to update, I would recommend setting up a testing environment (if you do not have one already – the free WP Staging plugin will let you create a quick copy of your live site that you can use for testing) and trying to install the latest versions again. If you’re still getting the errors, try running through the steps outlined here. If that doesn’t resolve this, the next step would be to try testing for conflicts with your theme and other plugins. Since this occurred after an update, it is possible that the current versions are not getting along with something else on your site.
Let me know how it goes!
Thanks,
Jennifer