diff --git a/libs/piqt/piqt.h b/libs/piqt/piqt.h
index 0a823a1..3d47cb1 100644
--- a/libs/piqt/piqt.h
+++ b/libs/piqt/piqt.h
@@ -360,17 +360,19 @@ BINARY_STREAM_READ (QImage) {
 
 /// pure Qt
 
-template <typename T> QByteArray qSerialize(const T & value) {
+template <typename T> QByteArray qSerialize(const T & value, int version = -1) {
 	QByteArray ret;
 	QDataStream s(&ret, QIODevice::ReadWrite);
+	if (version > 0) s.setVersion((QDataStream::Version)version);
 	s << value;
 	return ret;
 }
 
-template <typename T> T qDeserialize(const QByteArray & data) {
+template <typename T> T qDeserialize(const QByteArray & data, int version = -1) {
 	T ret;
 	if (!data.isEmpty()) {
 		QDataStream s(data);
+		if (version > 0) s.setVersion((QDataStream::Version)version);
 		s >> ret;
 	}
 	return ret;