Hi, Gordon. This is a great question. There are a couple of things to try.
Please make sure you first upgrade The Events Calendar (free version) before attempting to upgrade any add-ons. If you attempt to update add-ons first, you can get unexpected behaviors.
Second, if you’re having trouble getting the automatic updates to trigger, you can download the zip file for them from this site here: https://theeventscalendar.com/downloads/ Then, you’ll need to rename the existing add-on folder before attempting to update through the WP Admin interface.
Hope that helps!