diff --git a/lib/moodlelib.php b/lib/moodlelib.php
index 79e1a76..f9f4b6e 100644
--- a/lib/moodlelib.php
+++ b/lib/moodlelib.php
@@ -4061,8 +4061,8 @@ function &get_mailer($action='get') {
             get_mailer('flush');
         }
 
-        include_once($CFG->libdir.'/phpmailer/class.phpmailer.php');
-        $mailer = new phpmailer();
+        include_once($CFG->libdir.'/phpmailer/moodle_phpmailer.php');
+        $mailer = new moodle_phpmailer();
 
         $counter = 1;
 
diff --git a/lib/phpmailer/moodle_phpmailer.php b/lib/phpmailer/moodle_phpmailer.php
new file mode 100644
index 0000000..3617bb2
--- /dev/null
+++ b/lib/phpmailer/moodle_phpmailer.php
@@ -0,0 +1,61 @@
+<?php
+
+require_once($CFG->libdir.'/phpmailer/class.phpmailer.php');
+
+class moodle_phpmailer extends PHPMailer {
+
+    /**
+     * Set Moodle Defaults
+     */
+    public function __construct(){
+        global $CFG;
+        $this->Version   = 'Moodle '.$CFG->version;         // mailer version
+        $this->PluginDir = $CFG->libdir.'/phpmailer/';      // plugin directory (eg smtp plugin)
+        $this->CharSet   = 'UTF-8';
+    }
+
+    /**
+     * Extended AddCustomHeader function in order to stop duplicate 
+     * message-ids
+     * http://tracker.moodle.org/browse/MDL-3681
+     */
+    public function AddCustomHeader($custom_header) {
+        if(preg_match('/message-id:(.*)/i', $custom_header, $matches)){
+            $this->MessageID = $matches[1];
+            return true;
+        }else{
+            return parent::AddCustomHeader($custom_header);
+        }
+    }
+
+    /**
+     * Use internal moodles own textlib to encode mimeheaders
+     */
+    public function EncodeHeader ($str, $position = 'text') {
+        $textlib = textlib_get_instance();
+        $encoded = $textlib->encode_mimeheader($str, $this->CharSet);
+        if ($encoded !== false) {
+            $encoded = str_replace("\n", $this->LE, $encoded);
+            if ($position == 'phrase') {
+                return ("\"$encoded\"");
+            }
+            return $encoded;
+        }
+
+        return parent::EncodeHeader($str, $position);
+    }
+
+    /**
+     * Replaced function to fix tz bug:
+     * http://tracker.moodle.org/browse/MDL-12596
+     */
+    private static function RFCDate() {
+        $tz = date('Z');
+        $tzs = ($tz < 0) ? '-' : '+';
+        $tz = abs($tz);
+        $tz = (($tz - ($tz%3600) )/3600)*100 + ($tz%3600)/60; // fixed tz bug
+        $result = sprintf("%s %s%04d", date('D, j M Y H:i:s'), $tzs, $tz);
+
+        return $result;
+    }
+}