This Block installed OK, and in fact still runs well in Moodle 3.1 - perhaps because it's operation is actually fairly simple and straightforward. It still functions as documented, including the notification to Students (if used) and booking in Calendars correctly. The only slight niggle is the formatting of the Block does not seem to adhere to the newer Block formatting (see below).
Very easy to use . You can try this Block yourself for real on our public plugins site: http://plugins.moodlebites.com