Rated 4 out of 5 stars

Does not work anymore with Thunderbird 63.0beta

This review is for a previous version of the add-on (2.0.8). 

That's correct. Release versions of Enigmail typically don't work with beta versions of Thunderbird. You have to use the nightly builds of Enigmail provided on https://enigmail.net/index.php/en/download/nightly-build