Index: program/include/rcube_shared.inc
===================================================================
--- program/include/rcube_shared.inc	(revision 0144c50fc474c5f0145f3ac1fd2f0d2360e21695)
+++ program/include/rcube_shared.inc	(revision db401bfb0a3891b06a4c70207f88942e7628ac11)
@@ -541,5 +541,5 @@
     {
     $key  = 'HTTP_' . strtoupper(strtr($name, '-', '_'));
-    $hdrs = array_change_key_case($_SERVER[$key], CASE_UPPER);
+    $hdrs = array_change_key_case($_SERVER, CASE_UPPER);
     }
   if (isset($hdrs[$key]))