diff --git a/include/pear/Mail/mimeDecode.php b/include/pear/Mail/mimeDecode.php
index 9b1e208be17859b5380910fd0ce9f77aff1d7ada..02f00f068863a4d0ae08bb9628e93428371f9ca3 100644
--- a/include/pear/Mail/mimeDecode.php
+++ b/include/pear/Mail/mimeDecode.php
@@ -645,7 +645,10 @@ class Mail_mimeDecode extends PEAR
         $input = preg_replace("/=\r?\n/", '', $input);
 
         // Replace encoded characters
-		$input = preg_replace('/=([a-f0-9]{2})/ie', "chr(hexdec('\\1'))", $input);
+       $input = preg_replace_callback('/=([a-f0-9]{2})/i',
+               create_function('$matches',
+                   ' return chr(hexdec($matches[0]));'),
+               $input);
 
         return $input;
     }