alexknowshtml/postmark-approved-wordpress-plugin — pull request #5 by morrisdj (2014-08-31 20:49:32+00:00)
Title: Add support for attachments

I've added the support to allow sending of attachments to the plugin.
The attachments parameter works the same way as the original wp_mail.
"Files to attach: a single filename, an array of filenames, or a newline-delimited string list of multiple filenames."