diff --git a/zipcode.it.inc b/zipcode.it.inc
index 0696ac2..8888c5b 100644
--- a/zipcode.it.inc
+++ b/zipcode.it.inc
@@ -16,9 +16,9 @@
  */
 function valid_it_zipcode($zipcodestring) {
 
-  $zipcodestring = trim($zipcodestring);
+  $zipcodestring = strtoupper(trim($zipcodestring));
 
-  if (!preg_match("/^(V-|I-|IT-)?[0-9]{4}$/i",$zipcodestring)) {
+  if (!preg_match("/^(V-|I-|IT-)?[0-9]{5}$/",$zipcodestring)) {
   	return FALSE;
   }
   //right now just do a quick check ==> has to be improved