diff --git a/README.md b/README.md
index b8472a8e..bb00df62 100644
--- a/README.md
+++ b/README.md
@@ -25,8 +25,7 @@ can be found at https://en.bitcoin.it/wiki/Script
 ```Go
 	pkscript := txS.TxOut[origintxidx].PkScript
 	engine, err := btcscript.NewScript(sigScript, pkscript, txInIdx,
-		txValidator, pver,
-		timestamp.After(btcscript.Bip16Activation))
+		txValidator, timestamp.After(btcscript.Bip16Activation))
 	err = engine.Execute()
 ```
 
diff --git a/doc.go b/doc.go
index 0fb28f23..ebca20c6 100644
--- a/doc.go
+++ b/doc.go
@@ -40,13 +40,12 @@ engine to validate a transaction.
 
 	// ValidateTx validates the txIdx'th input of tx. The output transaction
 	// corresponding to the this input is the txInIdx'th output of txIn. The
-	// block timestamp of tx is timestamp and the protocol version involved
-	// is pver.
-	func ValidateTx(tx *btcwire.MsgTx, txIdx int, txIn *btcwire.MsgTx, txInIdx int, pver int, timestamp time.Time) {
+	// block timestamp of tx is timestamp.
+	func ValidateTx(tx *btcwire.MsgTx, txIdx int, txIn *btcwire.MsgTx, txInIdx int, timestamp time.Time) {
 		pkScript := txIn.TxOut[txInIdx].PkScript
 		sigScript := tx.txIn[TxIdx]
 		engine, err := btcscript.NewScript(sigScript, pkScript, txInIdx,
-			tx, pver, timestamp.After(btcscript.Bip16Activation))
+			tx, timestamp.After(btcscript.Bip16Activation))
 		return engine.Execute()
 	}
 
diff --git a/opcode_test.go b/opcode_test.go
index 5df53f3c..61eb31c0 100644
--- a/opcode_test.go
+++ b/opcode_test.go
@@ -494,7 +494,7 @@ func testScript(t *testing.T, script []byte) (err error) {
 	tx.TxOut[0].PkScript = script
 
 	engine, err := btcscript.NewScript(tx.TxIn[0].SignatureScript,
-		tx.TxOut[0].PkScript, 0, tx, 1, false)
+		tx.TxOut[0].PkScript, 0, tx, false)
 	if err != nil {
 		return err
 	}
@@ -3875,7 +3875,7 @@ func testOpcode(t *testing.T, test *detailedTest) {
 	tx.TxOut[0].PkScript = test.script
 
 	engine, err := btcscript.NewScript(tx.TxIn[0].SignatureScript,
-		tx.TxOut[0].PkScript, 0, tx, 1, false)
+		tx.TxOut[0].PkScript, 0, tx, false)
 	if err != nil {
 		if err != test.expectedReturn {
 			t.Errorf("Error return not expected %s: %v %v",
diff --git a/script.go b/script.go
index 8e6fd052..581cf1eb 100644
--- a/script.go
+++ b/script.go
@@ -147,7 +147,6 @@ type Script struct {
 	astack          Stack // alt stack
 	tx              btcwire.MsgTx
 	txidx           int
-	pver            uint32
 	condStack       []int
 	numOps          int
 	bip16           bool     // treat execution as pay-to-script-hash
@@ -341,7 +340,7 @@ func unparseScript(pops []parsedOpcode) []byte {
 // a signature script scriptSig and a pubkeyscript scriptPubKey. If bip16 is
 // true then it will be treated as if the bip16 threshhold has passed and thus
 // pay-to-script hash transactions will be fully validated.
-func NewScript(scriptSig []byte, scriptPubKey []byte, txidx int, tx *btcwire.MsgTx, pver uint32, bip16 bool) (*Script, error) {
+func NewScript(scriptSig []byte, scriptPubKey []byte, txidx int, tx *btcwire.MsgTx, bip16 bool) (*Script, error) {
 	var m Script
 	scripts := [][]byte{scriptSig, scriptPubKey}
 	m.scripts = make([][]parsedOpcode, len(scripts))
@@ -372,7 +371,6 @@ func NewScript(scriptSig []byte, scriptPubKey []byte, txidx int, tx *btcwire.Msg
 
 	m.tx = *tx
 	m.txidx = txidx
-	m.pver = pver
 	m.condStack = []int{OpCondTrue}
 
 	return &m, nil
@@ -692,7 +690,7 @@ func (s *Script) calcScriptHash(script []parsedOpcode, hashType byte) []byte {
 	}
 
 	var wbuf bytes.Buffer
-	txCopy.BtcEncode(&wbuf, s.pver)
+	txCopy.Serialize(&wbuf)
 	// Append LE 4 bytes hash type
 	binary.Write(&wbuf, binary.LittleEndian, uint32(hashType))
 
diff --git a/script_test.go b/script_test.go
index ac05927a..5f203792 100644
--- a/script_test.go
+++ b/script_test.go
@@ -1204,7 +1204,7 @@ var txTests = []txTest{
 func testTx(t *testing.T, test txTest) {
 	engine, err := btcscript.NewScript(
 		test.tx.TxIn[test.idx].SignatureScript, test.pkScript,
-		test.idx, test.tx, 70001, test.bip16)
+		test.idx, test.tx, test.bip16)
 	if err != nil {
 		if err != test.parseErr {
 			t.Errorf("Failed to parse %s: got \"%v\" expected "+
@@ -1731,7 +1731,7 @@ func TestBadPC(t *testing.T) {
 
 	for _, test := range pcTests {
 		engine, err := btcscript.NewScript(tx.TxIn[0].SignatureScript,
-			pkScript, 0, tx, 70001, false)
+			pkScript, 0, tx, false)
 		if err != nil {
 			t.Errorf("Failed to create script: %v", err)
 		}
@@ -1801,7 +1801,7 @@ func TestCheckErrorCondition(t *testing.T) {
 	}
 
 	engine, err := btcscript.NewScript(tx.TxIn[0].SignatureScript, pkScript,
-		0, tx, 70001, false)
+		0, tx, false)
 	if err != nil {
 		t.Errorf("failed to create script: %v", err)
 	}