Rated 5 out of 5 stars
Works like a charm on Thunderbird 60.0 + Thunderstats 1.4.2 (no errors of any kind)
Very useful addon to know how many emails you are dealing with, and very customizable also.
You can select both the time interval, and customize it further; by default Today, Yesterday, Last 7 days; and also you can see the Top email Senders&Top email Recipients (by default this list is Top 10 you can select any number)
Last but a plus, very nice looking, pretty graphics and colors.