I've been using this plugin forever and I love it! It always works no matter the version of WP I have. I've always customized my emails for every theme change to correspond with our look and have received great comments on how nice they look. Recently though, I decided to just use the default template as my health has been suffering and I do not have the energy to customize it right now, of course it too looks great.
However, I noticed that the WordPress logo in the bottom right of the template has a different file name than what my installation (3.8) uses. It is relatively small non-issue but anyway... This is the file name for the logo if you do use it, I don't have a wp-logo.png it's actually w-logo-blue.png or w-logo-white.png.
Just a note in case anyone else is as particular as me! :)