diff --git a/smpp/pdu/types.go b/smpp/pdu/types.go
index d2b0bcc..c003f0b 100644
--- a/smpp/pdu/types.go
+++ b/smpp/pdu/types.go
@@ -308,8 +308,6 @@ func newDeliverSM(hdr *Header) *codec {
 			pdufield.DataCoding,
 			pdufield.SMDefaultMsgID,
 			pdufield.SMLength,
-			pdufield.UDHLength,
-			pdufield.GSMUserData,
 			pdufield.ShortMessage,
 		},
 	}