jaswrks
commented
8 years ago I see now why I was expecting to see a multipart message the other day when I was testing this in a video. The SMTP class that Comment Mail comes with does send a multipart message. However, as it stands, that's only used if SMTP credentials are configured. Otherwise, it is sent to wp_mail() with only content-type: text/html here.
It is that send() method that handles all outbound mail in the CM project. If SMTP credentials are used, you can see it behaves differently.
It would be nice if Comment Mail would not only sent plain-text versions of the HTML email notifications (which it does not currently do), but if also had an option that allowed you to specifically toggle plain-text-only emails, so that only a plain-text version would be sent. With that option enabled, a site owner could strip all HTML tags from the email templates and greatly simplify them.
WordPress notification emails are already plain-text and StCR notification emails are also plain-text. With Comment Mail, it's currently only possible to send HTML notification emails