http://www.elkarte.net/community/index.php?scheduled=mailq;ts=1453904261That's all there is to it.
/.../sources/subs/Mail.subs.php
Line: 1068
// Line breaks need to be \r\n only in windows or for SMTP.
$line_break = !empty($context['server']['is_windows']) || !$use_sendmail ? "\r\n" : "\n";
foreach ($emails as $key => $email)
{
// Use the right mail resource
if ($use_sendmail)
{
$email['subject'] = strtr($email['subject'], array("\r" => '', "\n" => ''));
$email['body_fail'] = $email['body'];
if (!empty($modSettings['mail_strip_carriage']))
{
$email['body'] = strtr($email['body'], array("\r" => ''));
$email['headers'] = strtr($email['headers'], array("\r" => ''));
}
$need_break = substr($email['headers'], -1) === "\n" || substr($email['headers'], -1) === "\r" ? false : true;
// Create our unique reply to email header if this message needs one
$unq_id = '';