Rated 5 out of 5 stars

Update: Thanks for the quick reply, appreciated. Postbox wrote: "contact the original add-on developer directly or disable the add-on". So I had hope they did not lie. Anyway thanks. Giving you for the TB version a 5/5

This review is for a previous version of the add-on (1.5.1). 

The Postbox version of Enigmail are provided by Postbox. It's not the fault of Enigmail that Postbox doesn't publish their source code, such that official releases of Enigmail don't work on Postbox ...