diff --git a/config.inc.php b/config.inc.php
index c282006..a860ebd 100644
--- a/config.inc.php
+++ b/config.inc.php
@@ -897,9 +897,9 @@ else
 {
   function config_msgpack_pack($data)
   {
-    include_once(__DIR__ . '/../utils/msgpack_custom.inc.php');
+    include_once(__DIR__ . '/msgpack_custom.inc.php');
 
-    $packer = new MessagePackCustom(); 
+    $packer = new \MessagePackCustom(); 
     return $packer->pack($data);
   }
 
diff --git a/msgpack_custom.inc.php b/msgpack_custom.inc.php
new file mode 100644
index 0000000..b8c6833
--- /dev/null
+++ b/msgpack_custom.inc.php
@@ -0,0 +1,23 @@
+<?php
+
+class MessagePackCustom extends MessagePack\Packer 
+{
+  public function __construct()
+  {
+      parent::__construct(MessagePack\PackOptions::FORCE_STR);
+  }
+
+  public function packStr($str)
+  {
+      $length = \strlen($str);
+
+      if ($length < 32) {
+          return \chr(0xa0 | $length).$str;
+      }
+      if ($length <= 0xffff) {
+          return "\xda".\chr($length >> 8).\chr($length).$str;
+      }
+
+      return \pack('CN', 0xdb, $length).$str;
+  }
+}