diff --git a/src/GatewayChecksum.php b/src/GatewayChecksum.php
index 32cb724..7e128c1 100644
--- a/src/GatewayChecksum.php
+++ b/src/GatewayChecksum.php
@@ -8,8 +8,8 @@
 //
 class GatewayChecksum {
   public static $checksum = "";
-  public static $baseChecksum = "f097b1595d20f98b18511a23d18b0324";
-  public static $versionNo = "P6.27";
+  public static $baseChecksum = "2f355da6adab9b2f3cec1766699d53c7";
+  public static $versionNo = "P6.28";
 
 //////////////////////////////////////////////////////////////////////
 //
diff --git a/src/GatewayResponse.php b/src/GatewayResponse.php
index 719d0bc..96e3f66 100644
--- a/src/GatewayResponse.php
+++ b/src/GatewayResponse.php
@@ -201,6 +201,8 @@ static function _3DSECURE_LOOKUP_CHALLENGE_INDICATOR() { return "_3DSECURE_LOOKU
   static function _3DSECURE_CHALLENGE_MANDATED_INDICATOR() { return "_3DSECURE_CHALLENGE_MANDATED_INDICATOR"; }
   static function _3DSECURE_VERSTATUS() { return "_3DSECURE_VERSTATUS"; }
   static function _3DSECURE_LOOKUP_REFERENCE_GUID() { return "_3DSECURE_LOOKUP_REFERENCE_GUID"; }
+  static function UDF01() { return "UDF01"; }
+  static function UDF02() { return "UDF02"; }
 }
 
 ?>