Ticket #22492: patchfile.txt

--- wp-includes/class-phpmailer.php   Sun Nov 18 01:56:59 2012 +0000
+++ wp-includes/class-phpmailer.php   Sun Nov 18 03:17:01 2012 +0000
@@ -1238,11 +1238,17 @@
     }

     // Add custom headers
+    $mime_version_encountered = false; // sometimes mime-version is already included in custom headers, and some mail servers reject messages with duplicate mime-version headers.
     for($index = 0; $index < count($this->CustomHeader); $index++) {
       $result .= $this->HeaderLine(trim($this->CustomHeader[$index][0]), $this->EncodeHeader(trim($this->CustomHeader[$index][1])));
+      if (strcasecmp(trim($this->CustomHeader[$index][0]), 'mime-version') == 0) {
+         $mime_version_encountered = true;
+      }
     }
     if (!$this->sign_key_file) {
-      $result .= $this->HeaderLine('MIME-Version', '1.0');
+      if (!$mime_version_encountered) {
+         $result .= $this->HeaderLine('MIME-Version', '1.0');
+      }
       $result .= $this->GetMailMIME();
     }