Changes

The documentation is really poor for the mail handling aspects. To be fair, it's complicated. But I wish I had the time to contribute to the documentation. Maybe someday. The best succinct resource I found for adding a 'Newsletter subscription form' is at https://forum.civicrm.org/index.php?topic=18364.0And this old post from 2013 does a pretty good job of explaining the variations on [https://warrenpost.wordpress.com/2013/09/13/civicrm-mail/ setting up 'Bounce Handling' and 'Email to Activity' handling].