Index: wp-includes/class-phpmailer.php
===================================================================
--- wp-includes/class-phpmailer.php	(revision 21078)
+++ wp-includes/class-phpmailer.php	(working copy)
@@ -760,13 +760,13 @@
     } else {
       if ($this->SingleTo === true && count($toArr) > 1) {
         foreach ($toArr as $key => $val) {
-          $rt = @mail($val, $this->EncodeHeader($this->SecureHeader($this->Subject)), $body, $header, $params);
+          $rt = @mail($val, $this->EncodeHeader($this->SecureHeader($this->Subject)), $body, $header);
           // implement call back function if it exists
           $isSent = ($rt == 1) ? 1 : 0;
           $this->doCallback($isSent, $val, $this->cc, $this->bcc, $this->Subject, $body);
         }
       } else {
-        $rt = @mail($to, $this->EncodeHeader($this->SecureHeader($this->Subject)), $body, $header, $params);
+        $rt = @mail($to, $this->EncodeHeader($this->SecureHeader($this->Subject)), $body, $header);
         // implement call back function if it exists
         $isSent = ($rt == 1) ? 1 : 0;
         $this->doCallback($isSent, $to, $this->cc, $this->bcc, $this->Subject, $body);