Rated 5 out of 5 stars

This addon is a big relief, as it allows me to keep a central oversight of my mix of caldav, ics and MS-exchange calendars in thunderbird.
It's still depressing that MS has been refusing to support caldav out of the box, but I'm grateful that the developer took the initiative to create this functional workaround.

This review is for a previous version of the add-on (1.20).