Rated 4 out of 5 stars

The add-on worked well and silent in the background, until Thunderbird made its update to 78.7.1. (64-bit on Ubuntu 20). Now, unfortunately, exchange is just not syncing any more... would be glad if that could be fixed!

Many thanks for the quick reply! I can't edit or add/remove accounts... that function has disappeared at the TB Sync options. Just opened a thread in Thunderbird help, too. There I will upload a screenshot... see https://support.mozilla.org/de/questions/1328759#answer-1397622

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

Remove the account in TbSync and set it up anew, maybe use the new modern auth method.