Rated 5 out of 5 stars

I have been using the SOGO-connector previously to manage contacts in Thunderbird. This never worked well, particularly it synced poorly and unreliably with my cloud and other devices.
For the first time, I now have the feeling that I can use an app which not only does the job reliably, but also has all features for professional contact management (for computer beginners, it might have too many features though). It works perfectly with my Nextcloud installation, thus allowing me to store and manage my data on my own infrastructure.
I can definitely recommend this important Addon to Thunderbird which fills a big gap in the functionality of Thunderbird. @community: please help to spread, promote, support and improve this Addon !

This review is for a previous version of the add-on (27.3).