link in HTML email templates

the link in the line For an in-depth tutorial on how to use this plugin, check out the WPMU article about it!

gives a 404 error.

should be linked to

https://premium.wpmudev.org/blog/pretty-and-responsive-wordpress-emails/

not

https://premium.wpmudev.org/blog/how-to-make-wordpress-emails-better-looking-and-responsive/