Rated 5 out of 5 stars

I've been using ExQuilla for some time and now I just tested it with the new Thunderbird 91. Setup and basic functionality are working fine. I can send/receive Emails without problems, so far so good.

I don't see any problems in paying a small annual fee, the developers are indeed working to maintain the addon for every new version of Thunderbird.

This review is for a previous version of the add-on (91.0).  This user has a previous review of this add-on.