[Plugin: Subscribe To Comments Reloaded] Cannot send emails due to duplicate header

PHPMailer (part of WordPress) unconditionally adds the “MIME-Version” header to outgoing email messages. This causes MTAs like Postfix and Exim to reject the emails due to duplicate headers.

There are two places in subscribe-to-comments-reloaded.php where I applied a simple patch:

// PhpMailer adds this header without checking if it already exists
// $headers = "MIME-Version: 1.0\n";
$headers = "From: $from_name <$from_email>\n";

http://wordpress.org/extend/plugins/subscribe-to-comments-reloaded/