// additional headers
if (!empty($email->getAdditionalMailHeader())) {
foreach ($email->getAdditionalMailHeader() as $name => $values) {
- // Skip the "Message-ID" header because PHP-Mailer is using its own
+ // Set the "Message-ID" header for PHP-Mailer directly
if ($name == 'Message-Id') {
- continue;
+ // implode all values to one entry, because there's only one value possible
+ $mailer->MessageID = trim(implode("", $values));
+ } else {
+ $mailer->addCustomHeader(trim($name), trim(implode("\n", $values)));
}
- $mailer->addCustomHeader(trim($name), trim(implode("\n", $values)));
}
}