diff --git a/src/libs/qmldebug/baseenginedebugclient.cpp b/src/libs/qmldebug/baseenginedebugclient.cpp
index 6e476692149..fbd0f0753e1 100644
--- a/src/libs/qmldebug/baseenginedebugclient.cpp
+++ b/src/libs/qmldebug/baseenginedebugclient.cpp
@@ -181,7 +181,7 @@ void BaseEngineDebugClient::statusChanged(ClientStatus status)
 
 void BaseEngineDebugClient::messageReceived(const QByteArray &data)
 {
-    QDataStream ds(data);
+    QmlDebugStream ds(data);
     int queryId;
     QByteArray type;
     ds >> type >> queryId;
@@ -254,7 +254,7 @@ quint32 BaseEngineDebugClient::addWatch(const PropertyReference &property)
     if (status() == Enabled) {
         id = getId();
         QByteArray message;
-        QDataStream ds(&message, QIODevice::WriteOnly);
+        QmlDebugStream ds(&message, QIODevice::WriteOnly);
         ds << QByteArray("WATCH_PROPERTY") << id << property.m_objectDebugId
            << property.m_name.toUtf8();
         sendMessage(message);
@@ -276,7 +276,7 @@ quint32 BaseEngineDebugClient::addWatch(const ObjectReference &object,
     if (status() == Enabled) {
         id = getId();
         QByteArray message;
-        QDataStream ds(&message, QIODevice::WriteOnly);
+        QmlDebugStream ds(&message, QIODevice::WriteOnly);
         ds << QByteArray("WATCH_EXPR_OBJECT") << id << object.m_debugId << expr;
         sendMessage(message);
     }
@@ -289,7 +289,7 @@ quint32 BaseEngineDebugClient::addWatch(int objectDebugId)
     if (status() == Enabled) {
         id = getId();
         QByteArray message;
-        QDataStream ds(&message, QIODevice::WriteOnly);
+        QmlDebugStream ds(&message, QIODevice::WriteOnly);
         ds << QByteArray("WATCH_OBJECT") << id << objectDebugId;
         sendMessage(message);
     }
@@ -306,7 +306,7 @@ void BaseEngineDebugClient::removeWatch(quint32 id)
 {
     if (status() == Enabled) {
         QByteArray message;
-        QDataStream ds(&message, QIODevice::WriteOnly);
+        QmlDebugStream ds(&message, QIODevice::WriteOnly);
         ds << QByteArray("NO_WATCH") << id;
         sendMessage(message);
     }
@@ -318,7 +318,7 @@ quint32 BaseEngineDebugClient::queryAvailableEngines()
     if (status() == Enabled) {
         id = getId();
         QByteArray message;
-        QDataStream ds(&message, QIODevice::WriteOnly);
+        QmlDebugStream ds(&message, QIODevice::WriteOnly);
         ds << QByteArray("LIST_ENGINES") << id;
         sendMessage(message);
     }
@@ -331,7 +331,7 @@ quint32 BaseEngineDebugClient::queryRootContexts(const EngineReference &engine)
     if (status() == Enabled && engine.m_debugId != -1) {
         id = getId();
         QByteArray message;
-        QDataStream ds(&message, QIODevice::WriteOnly);
+        QmlDebugStream ds(&message, QIODevice::WriteOnly);
         ds << QByteArray("LIST_OBJECTS") << id << engine.m_debugId;
         sendMessage(message);
     }
@@ -344,7 +344,7 @@ quint32 BaseEngineDebugClient::queryObject(int objectId)
     if (status() == Enabled && objectId != -1) {
         id = getId();
         QByteArray message;
-        QDataStream ds(&message, QIODevice::WriteOnly);
+        QmlDebugStream ds(&message, QIODevice::WriteOnly);
         ds << QByteArray("FETCH_OBJECT") << id << objectId << false <<
               true;
         sendMessage(message);
@@ -358,7 +358,7 @@ quint32 BaseEngineDebugClient::queryObjectRecursive(int objectId)
     if (status() == Enabled && objectId != -1) {
         id = getId();
         QByteArray message;
-        QDataStream ds(&message, QIODevice::WriteOnly);
+        QmlDebugStream ds(&message, QIODevice::WriteOnly);
         ds << QByteArray("FETCH_OBJECT") << id << objectId << true <<
               true;
         sendMessage(message);
@@ -374,7 +374,7 @@ quint32 BaseEngineDebugClient::queryExpressionResult(int objectDebugId,
     if (status() == Enabled && objectDebugId != -1) {
         id = getId();
         QByteArray message;
-        QDataStream ds(&message, QIODevice::WriteOnly);
+        QmlDebugStream ds(&message, QIODevice::WriteOnly);
         ds << QByteArray("EVAL_EXPRESSION") << id << objectDebugId << expr
            << engineId;
         sendMessage(message);
@@ -393,7 +393,7 @@ quint32 BaseEngineDebugClient::setBindingForObject(
     if (status() == Enabled && objectDebugId != -1) {
         id = getId();
         QByteArray message;
-        QDataStream ds(&message, QIODevice::WriteOnly);
+        QmlDebugStream ds(&message, QIODevice::WriteOnly);
         ds << QByteArray("SET_BINDING") << id << objectDebugId << propertyName
            << bindingExpression << isLiteralValue << source << line;
         sendMessage(message);
@@ -409,7 +409,7 @@ quint32 BaseEngineDebugClient::resetBindingForObject(
     if (status() == Enabled && objectDebugId != -1) {
         id = getId();
         QByteArray message;
-        QDataStream ds(&message, QIODevice::WriteOnly);
+        QmlDebugStream ds(&message, QIODevice::WriteOnly);
         ds << QByteArray("RESET_BINDING") << id << objectDebugId << propertyName;
         sendMessage(message);
     }
@@ -424,7 +424,7 @@ quint32 BaseEngineDebugClient::setMethodBody(
     if (status() == Enabled && objectDebugId != -1) {
         id = getId();
         QByteArray message;
-        QDataStream ds(&message, QIODevice::WriteOnly);
+        QmlDebugStream ds(&message, QIODevice::WriteOnly);
         ds << QByteArray("SET_METHOD_BODY") << id << objectDebugId
            << methodName << methodBody;
         sendMessage(message);
@@ -439,7 +439,7 @@ quint32 BaseEngineDebugClient::queryObjectsForLocation(
     if (status() == Enabled) {
         id = getId();
         QByteArray message;
-        QDataStream ds(&message, QIODevice::WriteOnly);
+        QmlDebugStream ds(&message, QIODevice::WriteOnly);
         ds << QByteArray("FETCH_OBJECTS_FOR_LOCATION") << id <<
               fileName << lineNumber << columnNumber << false <<
               true;
diff --git a/src/libs/qmldebug/declarativeenginedebugclient.cpp b/src/libs/qmldebug/declarativeenginedebugclient.cpp
index 662e32d03b6..069e2975702 100644
--- a/src/libs/qmldebug/declarativeenginedebugclient.cpp
+++ b/src/libs/qmldebug/declarativeenginedebugclient.cpp
@@ -29,6 +29,7 @@
 
 #include "declarativeenginedebugclient.h"
 #include "qmldebugconstants.h"
+#include "qmldebugclient.h"
 
 namespace QmlDebug {
 
@@ -49,7 +50,7 @@ quint32 DeclarativeEngineDebugClient::setBindingForObject(
     if (status() == Enabled && objectDebugId != -1) {
         id = getId();
         QByteArray message;
-        QDataStream ds(&message, QIODevice::WriteOnly);
+        QmlDebugStream ds(&message, QIODevice::WriteOnly);
         ds << QByteArray("SET_BINDING") << objectDebugId << propertyName
            << bindingExpression << isLiteralValue << source << line;
         sendMessage(message);
@@ -65,7 +66,7 @@ quint32 DeclarativeEngineDebugClient::resetBindingForObject(
     if (status() == Enabled && objectDebugId != -1) {
         id = getId();
         QByteArray message;
-        QDataStream ds(&message, QIODevice::WriteOnly);
+        QmlDebugStream ds(&message, QIODevice::WriteOnly);
         ds << QByteArray("RESET_BINDING") << objectDebugId << propertyName;
         sendMessage(message);
     }
@@ -80,7 +81,7 @@ quint32 DeclarativeEngineDebugClient::setMethodBody(
     if (status() == Enabled && objectDebugId != -1) {
         id = getId();
         QByteArray message;
-        QDataStream ds(&message, QIODevice::WriteOnly);
+        QmlDebugStream ds(&message, QIODevice::WriteOnly);
         ds << QByteArray("SET_METHOD_BODY") << objectDebugId
            << methodName << methodBody;
         sendMessage(message);
@@ -90,7 +91,7 @@ quint32 DeclarativeEngineDebugClient::setMethodBody(
 
 void DeclarativeEngineDebugClient::messageReceived(const QByteArray &data)
 {
-    QDataStream ds(data);
+    QmlDebugStream ds(data);
     QByteArray type;
     ds >> type;
 
diff --git a/src/libs/qmldebug/qmldebugclient.cpp b/src/libs/qmldebug/qmldebugclient.cpp
index 6fd35d3c130..ff8d7d10b09 100644
--- a/src/libs/qmldebug/qmldebugclient.cpp
+++ b/src/libs/qmldebug/qmldebugclient.cpp
@@ -38,6 +38,8 @@
 namespace QmlDebug {
 
 const int protocolVersion = 1;
+int QmlDebugClient::s_dataStreamVersion = QDataStream::Qt_4_7;
+
 const QString serverId = QLatin1String("QDeclarativeDebugServer");
 const QString clientId = QLatin1String("QDeclarativeDebugClient");
 
@@ -95,7 +97,8 @@ void QmlDebugConnectionPrivate::advertisePlugins()
 void QmlDebugConnectionPrivate::connected()
 {
     QPacket pack;
-    pack << serverId << 0 << protocolVersion << plugins.keys();
+    QDataStream str;
+    pack << serverId << 0 << protocolVersion << plugins.keys() << QDataStream().version();
     protocol->send(pack);
     q->flush();
 }
@@ -131,6 +134,12 @@ void QmlDebugConnectionPrivate::readyRead()
                         serverPlugins.insert(pluginNames.at(i), pluginVersion);
                     }
 
+                    if (!pack.isEmpty()) {
+                        pack >> QmlDebugClient::s_dataStreamVersion;
+                        if (QmlDebugClient::s_dataStreamVersion
+                                > QDataStream().version())
+                            qWarning() << "Server returned invalid data stream version!";
+                    }
                     validHello = true;
                 }
             }
@@ -409,6 +418,30 @@ void QmlDebugClient::messageReceived(const QByteArray &)
 {
 }
 
+QmlDebugStream::QmlDebugStream()
+    : QDataStream()
+{
+    setVersion(QmlDebugClient::s_dataStreamVersion);
+}
+
+QmlDebugStream::QmlDebugStream(QIODevice *d)
+    : QDataStream(d)
+{
+    setVersion(QmlDebugClient::s_dataStreamVersion);
+}
+
+QmlDebugStream::QmlDebugStream(QByteArray *ba, QIODevice::OpenMode flags)
+    : QDataStream(ba, flags)
+{
+    setVersion(QmlDebugClient::s_dataStreamVersion);
+}
+
+QmlDebugStream::QmlDebugStream(const QByteArray &ba)
+    : QDataStream(ba)
+{
+    setVersion(QmlDebugClient::s_dataStreamVersion);
+}
+
 } // namespace QmlDebug
 
 #include <qmldebugclient.moc>
diff --git a/src/libs/qmldebug/qmldebugclient.h b/src/libs/qmldebug/qmldebugclient.h
index d33b639fec8..c337c355b2f 100644
--- a/src/libs/qmldebug/qmldebugclient.h
+++ b/src/libs/qmldebug/qmldebugclient.h
@@ -103,6 +103,18 @@ private:
     friend class QmlDebugConnection;
     friend class QmlDebugConnectionPrivate;
     QScopedPointer<QmlDebugClientPrivate> d_ptr;
+
+public:
+    static int s_dataStreamVersion;
+};
+
+class QMLDEBUG_EXPORT QmlDebugStream : public QDataStream
+{
+public:
+    QmlDebugStream();
+    explicit QmlDebugStream(QIODevice *d);
+    QmlDebugStream(QByteArray *ba, QIODevice::OpenMode flags);
+    QmlDebugStream(const QByteArray &ba);
 };
 
 } // namespace QmlDebug
diff --git a/src/plugins/debugger/qml/qmlv8debuggerclient.cpp b/src/plugins/debugger/qml/qmlv8debuggerclient.cpp
index 916beae49e3..fbfb6a9abcf 100644
--- a/src/plugins/debugger/qml/qmlv8debuggerclient.cpp
+++ b/src/plugins/debugger/qml/qmlv8debuggerclient.cpp
@@ -55,6 +55,7 @@
 #endif
 
 using namespace Core;
+using QmlDebug::QmlDebugStream;
 
 namespace Debugger {
 namespace Internal {
@@ -522,7 +523,7 @@ void QmlV8DebuggerClientPrivate::setBreakpoint(const QString type, const QString
     //    }
     if (type == _(EVENT)) {
         QByteArray params;
-        QDataStream rs(&params, QIODevice::WriteOnly);
+        QmlDebugStream rs(&params, QIODevice::WriteOnly);
         rs <<  target.toUtf8() << enabled;
         logSendMessage(QString(_("%1 %2 %3 %4")).arg(_(V8DEBUG), _(BREAKONSIGNAL), target, enabled?_("enabled"):_("disabled")));
         q->sendMessage(packMessage(BREAKONSIGNAL, params));
@@ -892,7 +893,7 @@ QByteArray QmlV8DebuggerClientPrivate::packMessage(const QByteArray &type, const
 {
     SDEBUG(message);
     QByteArray request;
-    QDataStream rs(&request, QIODevice::WriteOnly);
+    QmlDebugStream rs(&request, QIODevice::WriteOnly);
     QByteArray cmd = V8DEBUG;
     rs << cmd << type << message;
     return request;
@@ -1160,7 +1161,7 @@ void QmlV8DebuggerClient::getSourceFiles()
 
 void QmlV8DebuggerClient::messageReceived(const QByteArray &data)
 {
-    QDataStream ds(data);
+    QmlDebugStream ds(data);
     QByteArray command;
     ds >> command;
 
diff --git a/src/plugins/debugger/qml/qscriptdebuggerclient.cpp b/src/plugins/debugger/qml/qscriptdebuggerclient.cpp
index e01d0e4f9c7..9c66c25b9f9 100644
--- a/src/plugins/debugger/qml/qscriptdebuggerclient.cpp
+++ b/src/plugins/debugger/qml/qscriptdebuggerclient.cpp
@@ -34,11 +34,14 @@
 #include <debugger/stackhandler.h>
 #include <debugger/debuggercore.h>
 #include <debugger/debuggerstringutils.h>
+#include <qmldebug/qmldebugclient.h>
 
 #include <QFileInfo>
 #include <QMessageBox>
 #include <utils/qtcassert.h>
 
+using QmlDebug::QmlDebugStream;
+
 namespace Debugger {
 namespace Internal {
 
@@ -138,7 +141,7 @@ QScriptDebuggerClient::~QScriptDebuggerClient()
 void QScriptDebuggerClient::executeStep()
 {
     QByteArray reply;
-    QDataStream rs(&reply, QIODevice::WriteOnly);
+    QmlDebugStream rs(&reply, QIODevice::WriteOnly);
     QByteArray cmd = "STEPINTO";
     rs << cmd;
     d->logSendMessage(QLatin1String(cmd));
@@ -148,7 +151,7 @@ void QScriptDebuggerClient::executeStep()
 void QScriptDebuggerClient::executeStepOut()
 {
     QByteArray reply;
-    QDataStream rs(&reply, QIODevice::WriteOnly);
+    QmlDebugStream rs(&reply, QIODevice::WriteOnly);
     QByteArray cmd = "STEPOUT";
     rs << cmd;
     d->logSendMessage(QLatin1String(cmd));
@@ -158,7 +161,7 @@ void QScriptDebuggerClient::executeStepOut()
 void QScriptDebuggerClient::executeNext()
 {
     QByteArray reply;
-    QDataStream rs(&reply, QIODevice::WriteOnly);
+    QmlDebugStream rs(&reply, QIODevice::WriteOnly);
     QByteArray cmd = "STEPOVER";
     rs << cmd;
     d->logSendMessage(QLatin1String(cmd));
@@ -168,7 +171,7 @@ void QScriptDebuggerClient::executeNext()
 void QScriptDebuggerClient::executeStepI()
 {
     QByteArray reply;
-    QDataStream rs(&reply, QIODevice::WriteOnly);
+    QmlDebugStream rs(&reply, QIODevice::WriteOnly);
     QByteArray cmd = "STEPINTO";
     rs << cmd;
     d->logSendMessage(QLatin1String(cmd));
@@ -189,7 +192,7 @@ void QScriptDebuggerClient::executeRunToLine(const ContextData &data)
 void QScriptDebuggerClient::continueInferior()
 {
     QByteArray reply;
-    QDataStream rs(&reply, QIODevice::WriteOnly);
+    QmlDebugStream rs(&reply, QIODevice::WriteOnly);
     QByteArray cmd = "CONTINUE";
     rs << cmd;
     d->logSendMessage(QLatin1String(cmd));
@@ -199,7 +202,7 @@ void QScriptDebuggerClient::continueInferior()
 void QScriptDebuggerClient::interruptInferior()
 {
     QByteArray reply;
-    QDataStream rs(&reply, QIODevice::WriteOnly);
+    QmlDebugStream rs(&reply, QIODevice::WriteOnly);
     QByteArray cmd = "INTERRUPT";
     rs << cmd;
     d->logSendMessage(QLatin1String(cmd));
@@ -234,7 +237,7 @@ void QScriptDebuggerClient::resetSession()
 void QScriptDebuggerClient::activateFrame(int index)
 {
     QByteArray reply;
-    QDataStream rs(&reply, QIODevice::WriteOnly);
+    QmlDebugStream rs(&reply, QIODevice::WriteOnly);
     QByteArray cmd = "ACTIVATE_FRAME";
     rs << cmd
        << index;
@@ -287,7 +290,7 @@ void QScriptDebuggerClient::changeBreakpoint(const BreakpointModelId &id)
 void QScriptDebuggerClient::synchronizeBreakpoints()
 {
     QByteArray reply;
-    QDataStream rs(&reply, QIODevice::WriteOnly);
+    QmlDebugStream rs(&reply, QIODevice::WriteOnly);
     QByteArray cmd = "BREAKPOINTS";
     rs << cmd
        << d->breakpoints;
@@ -314,7 +317,7 @@ void QScriptDebuggerClient::assignValueInDebugger(const WatchData *data,
                                                   const QVariant &valueV)
 {
     QByteArray reply;
-    QDataStream rs(&reply, QIODevice::WriteOnly);
+    QmlDebugStream rs(&reply, QIODevice::WriteOnly);
     QByteArray cmd = "EXEC";
     rs << cmd;
     QString expression = QString(_("%1 = %2;")).arg(expr).arg(valueV.toString());
@@ -328,7 +331,7 @@ void QScriptDebuggerClient::assignValueInDebugger(const WatchData *data,
 void QScriptDebuggerClient::updateWatchData(const WatchData &data)
 {
     QByteArray reply;
-    QDataStream rs(&reply, QIODevice::WriteOnly);
+    QmlDebugStream rs(&reply, QIODevice::WriteOnly);
     QByteArray cmd = "EXEC";
     rs << cmd;
     rs << data.iname << data.name;
@@ -340,7 +343,7 @@ void QScriptDebuggerClient::updateWatchData(const WatchData &data)
 void QScriptDebuggerClient::executeDebuggerCommand(const QString &command)
 {
     QByteArray reply;
-    QDataStream rs(&reply, QIODevice::WriteOnly);
+    QmlDebugStream rs(&reply, QIODevice::WriteOnly);
     QByteArray cmd = "EXEC";
     QByteArray console = "console";
     rs << cmd << console << command;
@@ -353,7 +356,7 @@ void QScriptDebuggerClient::synchronizeWatchers(const QStringList &watchers)
 {
     // send watchers list
     QByteArray reply;
-    QDataStream rs(&reply, QIODevice::WriteOnly);
+    QmlDebugStream rs(&reply, QIODevice::WriteOnly);
     QByteArray cmd = "WATCH_EXPRESSIONS";
     rs << cmd;
     d->logSendMessage(QString::fromLatin1("%1 (%2)").arg(QLatin1String(cmd),
@@ -368,7 +371,7 @@ void QScriptDebuggerClient::expandObject(const QByteArray &iname, quint64 object
         return;
 
     QByteArray reply;
-    QDataStream rs(&reply, QIODevice::WriteOnly);
+    QmlDebugStream rs(&reply, QIODevice::WriteOnly);
     QByteArray cmd = "EXPAND";
     rs << cmd;
     rs << iname << objectId;
@@ -381,7 +384,7 @@ void QScriptDebuggerClient::sendPing()
 {
     d->ping++;
     QByteArray reply;
-    QDataStream rs(&reply, QIODevice::WriteOnly);
+    QmlDebugStream rs(&reply, QIODevice::WriteOnly);
     QByteArray cmd = "PING";
     rs << cmd;
     rs << d->ping;
@@ -392,7 +395,7 @@ void QScriptDebuggerClient::sendPing()
 void QScriptDebuggerClient::messageReceived(const QByteArray &data)
 {
     QByteArray rwData = data;
-    QDataStream stream(&rwData, QIODevice::ReadOnly);
+    QmlDebugStream stream(&rwData, QIODevice::ReadOnly);
 
     QByteArray command;
     stream >> command;