I have used it for years Rated 4 out of 5 stars

Over the years that I have been using Sync Kolab it has continuously improved. The efforts of the author are to be commended. There were problems in the beginning that almost caused me to quit using it, but over time, most of my objections were resolved. Sync Kolab's current reliability and the availability of Lightning have made Thunderbird my primary email client.

This review is for a previous version of the add-on (0.6.0).