Okay! I got it working! (I don't know if I did a crude job of it as I don't know PHP, but it's working)
Here's how I did it for anyone else who has problems, I guess. (Hopefully someone will correct any wrong code in here)
1. I went into inc/functions.php and found
//
// MyBB mail wrapper (soon to be a class)
//
function mymail($to, $subject, $message, $from="")
{
global $db, $mybb, $settings;
// For some reason sendmail/qmail doesn't like \r\n
$sendmail = @ini_get('sendmail_path');
if($sendmail)
{
$message = preg_replace("#(\r\n|\r|\n)#s", "\n", $message);
}
else
{
$message = preg_replace("#(\r\n|\r|\n)#s", "\r\n", $message);
}
if(strlen(trim($from)) == 0)
{
$from = "\"".$mybb->settings['bbname']." Mailer\" <".$mybb->settings['adminemail'].">";
}
mail($to, $subject, $message, "From: $from");
}
and then added headers and $headers to the mail() part, so it looked like this:
//
// MyBB mail wrapper (soon to be a class)
//
function mymail($to, $subject, $message, $from="")
{
global $db, $mybb, $settings;
// For some reason sendmail/qmail doesn't like \r\n
$sendmail = @ini_get('sendmail_path');
if($sendmail)
{
$message = preg_replace("#(\r\n|\r|\n)#s", "\n", $message);
}
else
{
$message = preg_replace("#(\r\n|\r|\n)#s", "\r\n", $message);
}
if(strlen(trim($from)) == 0)
{
$from = "\"".$mybb->settings['bbname']." Mailer\" <".$mybb->settings['adminemail'].">";
}
$headers .= "X-Priority: 1\n";
$headers .= "X-MSMail-Priority: High\n";
$headers .= "X-Mailer: My mailer";
mail($to, $subject, $message, $headers, "From: $from");
}
EDIT: It now sends it to the junk email folder, but at least it got there.