Rated 5 out of 5 stars

Very nice theme but not working with "RealPrevNextButtons for new Thunderbird versions 0.3" addon (https://addons.mozilla.org/de/thunderbird/addon/rpnb-new/). Maybe you can fix it in your next release. Thanks!

This review is for a previous version of the add-on (3.5.7). 

That's an obsolete extension, those buttons are built in these days (previous and next).