diff --git a/src/plugins/designer/designer.pro b/src/plugins/designer/designer.pro
index b6723b83c72..21559fdbea1 100644
--- a/src/plugins/designer/designer.pro
+++ b/src/plugins/designer/designer.pro
@@ -7,20 +7,26 @@ include(../../shared/designerintegrationv2/designerintegration.pri)
 include(cpp/cpp.pri)
 include(designer_dependencies.pri)
 
-# -- figure out shared dir location
-!exists($$[QT_INSTALL_HEADERS]/QtDesigner/private/qdesigner_integration_p.h) {
-    QT_SOURCE_TREE=$$fromfile($$(QTDIR)/.qmake.cache,QT_SOURCE_TREE)
-    INCLUDEPATH += $$QT_SOURCE_TREE/include
+INCLUDEPATH += ../../tools/utils
+
+minQtVersion(5, 0, 0) {
+    CONFIG += designer
+#   -- Fixme: Make tools available
+    INCLUDEPATH += $$QMAKE_INCDIR_QT/../../qttools/include
+} else {
+    # -- figure out shared dir location
+    !exists($$[QT_INSTALL_HEADERS]/QtDesigner/private/qdesigner_integration_p.h) {
+        QT_SOURCE_TREE=$$fromfile($$(QTDIR)/.qmake.cache,QT_SOURCE_TREE)
+        INCLUDEPATH += $$QT_SOURCE_TREE/include
+    }
+    INCLUDEPATH += $$QMAKE_INCDIR_QT/QtDesigner
+    qtAddLibrary(QtDesigner)
 }
 
-INCLUDEPATH += $$QMAKE_INCDIR_QT/QtDesigner \
-    ../../tools/utils
+QT += xml
 
-qtAddLibrary(QtDesigner)
 qtAddLibrary(QtDesignerComponents)
 
-QT+=xml
-
 HEADERS += formeditorplugin.h \
         formeditorfactory.h \
         formwindoweditor.h \
diff --git a/src/plugins/designer/designercontext.cpp b/src/plugins/designer/designercontext.cpp
index bddb1e9d810..e91f619add6 100644
--- a/src/plugins/designer/designercontext.cpp
+++ b/src/plugins/designer/designercontext.cpp
@@ -35,7 +35,12 @@
 #include "formeditorw.h"
 
 #include <QtDesigner/QDesignerFormEditorInterface>
-#include "qt_private/qdesigner_integration_p.h"
+
+#if QT_VERSION >= 0x050000
+#    include <QtDesigner/QDesignerIntegration>
+#else
+#    include "qt_private/qdesigner_integration_p.h"
+#endif
 
 #include <QtGui/QWidget>
 #include <QtCore/QDebug>
@@ -56,16 +61,18 @@ DesignerContext::DesignerContext(const Core::Context &context,
 
 QString DesignerContext::contextHelpId() const
 {
-    QString helpId;
     const QDesignerFormEditorInterface *core = FormEditorW::instance()->designerEditor();
-    // Present from Qt 4.5.1 onwards. This will show the class documentation
+#if QT_VERSION >= 0x050000
+    return core->integration()->contextHelpId();
+#else
+    QString helpId;
+     // Present from Qt 4.5.1 onwards. This will show the class documentation
     // scrolled to the current property.
     if (const qdesigner_internal::QDesignerIntegration *integration =
             qobject_cast<const qdesigner_internal::QDesignerIntegration*>(core->integration()))
         helpId = integration->contextHelpId();
-    if (debug)
-        qDebug() << "DesignerContext::contextHelpId" << m_widget << helpId;
     return helpId;
+#endif
 }
 
 } // namespace Internal
diff --git a/src/plugins/designer/formeditorw.cpp b/src/plugins/designer/formeditorw.cpp
index ce58f190347..7bb9c56c637 100644
--- a/src/plugins/designer/formeditorw.cpp
+++ b/src/plugins/designer/formeditorw.cpp
@@ -63,14 +63,18 @@
 #include <utils/qtcassert.h>
 
 #include <QtDesigner/QDesignerFormEditorPluginInterface>
-#include "qt_private/pluginmanager_p.h"
-
-#include "qt_private/iconloader_p.h"  // createIconSet
-#include "qt_private/qdesigner_formwindowmanager_p.h"
-#include "qt_private/formwindowbase_p.h"
 #include <QtDesigner/QDesignerFormEditorInterface>
 #include <QtDesigner/QDesignerComponents>
 
+#if QT_VERSION >= 0x050000
+#    include <QtDesigner/QDesignerFormWindowManagerInterface>
+#else
+#    include "qt_private/pluginmanager_p.h"
+#    include "qt_private/iconloader_p.h"  // createIconSet
+#    include "qt_private/qdesigner_formwindowmanager_p.h"
+#    include "qt_private/formwindowbase_p.h"
+#endif
+
 #include <QtDesigner/QDesignerWidgetBoxInterface>
 #include <QtDesigner/abstractobjectinspector.h>
 #include <QtDesigner/QDesignerPropertyEditorInterface>
@@ -117,7 +121,11 @@ static const char settingsGroup[] = "Designer";
 
 static inline QIcon designerIcon(const QString &iconName)
 {
+#if QT_VERSION >= 0x050000
+    const QIcon icon = QDesignerFormEditorInterface::createIcon(iconName);
+#else
     const QIcon icon = qdesigner_internal::createIconSet(iconName);
+#endif
     if (icon.isNull())
         qWarning() << "Unable to locate " << iconName;
     return icon;
@@ -180,7 +188,11 @@ FormEditorW::FormEditorW() :
     m_formeditor->setTopLevel(qobject_cast<QWidget *>(m_core->editorManager()));
     m_formeditor->setSettingsManager(new SettingsManager());
 
+#if QT_VERSION >= 0x050000
+    m_fwm = m_formeditor->formWindowManager();
+#else
     m_fwm = qobject_cast<qdesigner_internal::QDesignerFormWindowManager*>(m_formeditor->formWindowManager());
+#endif
     QTC_ASSERT(m_fwm, return);
 
     m_contexts.add(Designer::Constants::C_FORMEDITOR);
@@ -295,7 +307,11 @@ void FormEditorW::fullInit()
      * This will initialize our TabOrder, Signals and slots and Buddy editors.
      */
     QList<QObject*> plugins = QPluginLoader::staticInstances();
+#if QT_VERSION >= 0x050000
+    plugins += m_formeditor->pluginInstances();
+#else
     plugins += m_formeditor->pluginManager()->instances();
+#endif
     foreach (QObject *plugin, plugins) {
         if (QDesignerFormEditorPluginInterface *formEditorPlugin = qobject_cast<QDesignerFormEditorPluginInterface*>(plugin)) {
             if (!formEditorPlugin->isInitialized())
@@ -535,13 +551,22 @@ void FormEditorW::setupActions()
     // Commands that do not go into the editor toolbar
     createSeparator(this, am, m_contexts, mformtools, QLatin1String("FormEditor.Menu.Tools.Separator2"));
 
+#if QT_VERSION >= 0x050000
+    m_actionPreview = m_fwm->action(QDesignerFormWindowManagerInterface::DefaultPreviewAction);
+#else
     m_actionPreview = m_fwm->actionDefaultPreview();
+#endif
     QTC_ASSERT(m_actionPreview, return);
     addToolAction(m_actionPreview,  am,  m_contexts,
                    QLatin1String("FormEditor.Preview"), mformtools, tr("Alt+Shift+R"));
 
     // Preview in style...
+#if QT_VERSION >= 0x050000
+    m_actionGroupPreviewInStyle = m_fwm->actionGroup(QDesignerFormWindowManagerInterface::StyledPreviewActionGroup);
+#else
     m_actionGroupPreviewInStyle = m_fwm->actionGroupPreviewInStyle();
+#endif
+
     Core::ActionContainer *previewAC = createPreviewStyleMenu(am, m_actionGroupPreviewInStyle);
     m_previewInStyleMenu = previewAC->menu();
     mformtools->addMenu(previewAC);
@@ -562,14 +587,24 @@ void FormEditorW::setupActions()
                   tr("Shift+F4"));
 
     createSeparator(this, am, m_contexts, mformtools, QLatin1String("FormEditor.Menu.Tools.Separator4"));
+#if QT_VERSION >= 0x050000
+    QAction *actionFormSettings = m_fwm->action(QDesignerFormWindowManagerInterface::FormWindowSettingsDialogAction);
+#else
     QAction *actionFormSettings = m_fwm->actionShowFormWindowSettingsDialog();
+#endif
     addToolAction(actionFormSettings, am, m_contexts, QLatin1String("FormEditor.FormSettings"), mformtools);
 
     createSeparator(this, am, m_contexts, mformtools, QLatin1String("FormEditor.Menu.Tools.Separator5"));
     m_actionAboutPlugins = new QAction(tr("About Qt Designer plugins...."), this);
     addToolAction(m_actionAboutPlugins,  am,  m_contexts,
                    QLatin1String("FormEditor.AboutPlugins"), mformtools);
-    connect(m_actionAboutPlugins,  SIGNAL(triggered()), m_fwm, SLOT(aboutPlugins()));
+    connect(m_actionAboutPlugins,  SIGNAL(triggered()), m_fwm,
+#if QT_VERSION >= 0x050000
+            SLOT(showPluginDialog())
+#else
+            SLOT(aboutPlugins())
+#endif
+            );
     m_actionAboutPlugins->setEnabled(false);
 
     // FWM
@@ -706,12 +741,18 @@ EditorData FormEditorW::createEditor(QWidget *parent)
     // Create and associate form and text editor.
     EditorData data;
     m_fwm->closeAllPreviews();
+#if QT_VERSION >= 0x050000
+    QDesignerFormWindowInterface *form = m_fwm->createFormWindow(0);
+#else
     qdesigner_internal::FormWindowBase *form = qobject_cast<qdesigner_internal::FormWindowBase *>(m_fwm->createFormWindow(0));
+#endif
     QTC_ASSERT(form, return data);
     connect(form, SIGNAL(toolChanged(int)), this, SLOT(toolChanged(int)));
     ResourceHandler *resourceHandler = new ResourceHandler(form);
+#if QT_VERSION < 0x050000
     form->setDesignerGrid(qdesigner_internal::FormWindowBase::defaultDesignerGrid());
     qdesigner_internal::FormWindowBase::setupDefaultAction(form);
+#endif
     data.widgetHost = new SharedTools::WidgetHost( /* parent */ 0, form);
     DesignerXmlEditor *xmlEditor = new DesignerXmlEditor(form, parent);
     TextEditor::TextEditorSettings::instance()->initializeEditor(xmlEditor);
@@ -815,10 +856,13 @@ void FormEditorW::print()
     const QPrinter::Orientation oldOrientation =  m_core->printer()->orientation ();
     m_core->printer()->setFullPage(false);
     do {
-
         // Grab the image to be able to a suggest suitable orientation
         QString errorMessage;
+#if QT_VERSION >= 0x050000
+        const QPixmap pixmap = m_fwm->createPreviewPixmap();
+#else
         const QPixmap pixmap = m_fwm->createPreviewPixmap(&errorMessage);
+#endif
         if (pixmap.isNull()) {
             critical(tr("The image could not be created: %1").arg(errorMessage));
             break;
diff --git a/src/plugins/designer/formeditorw.h b/src/plugins/designer/formeditorw.h
index 67ba660db48..61c27a2bdb7 100644
--- a/src/plugins/designer/formeditorw.h
+++ b/src/plugins/designer/formeditorw.h
@@ -55,9 +55,13 @@ class QSignalMapper;
 class QSettings;
 class QToolBar;
 
+#if QT_VERSION >= 0x050000
+class QDesignerFormWindowManagerInterface;
+#else
 namespace qdesigner_internal {
     class QDesignerFormWindowManager;
 }
+#endif
 
 QT_END_NAMESPACE
 
@@ -172,7 +176,12 @@ private:
 
     QDesignerFormEditorInterface *m_formeditor;
     QDesignerIntegrationInterface *m_integration;
+
+#if QT_VERSION >= 0x050000
+    QDesignerFormWindowManagerInterface *m_fwm;
+#else
     qdesigner_internal::QDesignerFormWindowManager *m_fwm;
+#endif
     Core::ICore *m_core;
     InitializationStage m_initStage;
 
diff --git a/src/plugins/designer/formtemplatewizardpage.cpp b/src/plugins/designer/formtemplatewizardpage.cpp
index 9d2bdc954b1..9385e0ab1f2 100644
--- a/src/plugins/designer/formtemplatewizardpage.cpp
+++ b/src/plugins/designer/formtemplatewizardpage.cpp
@@ -34,7 +34,11 @@
 #include "formeditorw.h"
 #include "designerconstants.h"
 
-#include "qt_private/abstractnewformwidget_p.h"
+#if QT_VERSION >= 0x050000
+#    include <QtDesigner/QDesignerNewFormWidgetInterface>
+#else
+#    include "qt_private/abstractnewformwidget_p.h"
+#endif
 
 #include <QtCore/QDebug>
 #include <QtCore/QXmlStreamReader>
diff --git a/src/plugins/designer/formwindoweditor.cpp b/src/plugins/designer/formwindoweditor.cpp
index 4117a3b93e7..516795f27ff 100644
--- a/src/plugins/designer/formwindoweditor.cpp
+++ b/src/plugins/designer/formwindoweditor.cpp
@@ -34,7 +34,6 @@
 #include "formwindowfile.h"
 #include "designerconstants.h"
 #include "resourcehandler.h"
-#include "qt_private/formwindowbase_p.h"
 #include "designerxmleditor.h"
 #include <widgethost.h>
 
@@ -48,7 +47,12 @@
 #include <utils/qtcassert.h>
 #include <utils/fileutils.h>
 
-#include <QtDesigner/QDesignerFormWindowInterface>
+#if QT_VERSION >= 0x050000
+#    include <QtDesigner/QDesignerFormWindowInterface>
+#    include <QtCore/QBuffer>
+#else
+#    include "qt_private/formwindowbase_p.h"
+#endif
 
 #include <QtCore/QDebug>
 #include <QtCore/QFileInfo>
@@ -114,12 +118,17 @@ bool FormWindowEditor::createNew(const QString &contents)
         QApplication::restoreOverrideCursor();
     }
 
+#if QT_VERSION >= 0x050000
+    const bool success = form->setContents(contents);
+#else
     form->setContents(contents);
+    const bool success = form->mainContainer() != 0;
+#endif
 
     if (hasOverrideCursor)
         QApplication::setOverrideCursor(overrideCursor);
 
-    if (form->mainContainer() == 0)
+    if (!success)
         return false;
 
     syncXmlEditor(contents);
@@ -154,11 +163,17 @@ bool FormWindowEditor::open(QString *errorString, const QString &fileName, const
         return false;
 
     form->setFileName(absfileName);
-
-    const QString contents = QString::fromUtf8(reader.data());
-    form->setContents(contents);
+    QByteArray contents = reader.data();
+#if QT_VERSION >= 0x050000
+    QBuffer str(&contents);
+    str.open(QIODevice::ReadOnly);
+    if (!form->setContents(&str, errorString))
+        return false;
+#else
+    form->setContents(QString::fromUtf8(contents));
     if (!form->mainContainer())
         return false;
+#endif
     form->setDirty(fileName != realFileName);
     syncXmlEditor(contents);
 
@@ -249,9 +264,16 @@ QWidget *FormWindowEditor::toolBar()
 
 QString FormWindowEditor::contents() const
 {
+#if QT_VERSION >= 0x050000    // TODO: No warnings about spacers here
+    const QDesignerFormWindowInterface *fw = d->m_file.formWindow();
+    QTC_ASSERT(fw, return QString());
+    return fw->contents();
+#else
+    // No warnings about spacers here
     const qdesigner_internal::FormWindowBase *fw = qobject_cast<const qdesigner_internal::FormWindowBase *>(d->m_file.formWindow());
     QTC_ASSERT(fw, return QString());
-    return fw->fileContents(); // No warnings about spacers here
+    return fw->fileContents();
+#endif
 }
 
 TextEditor::BaseTextDocument *FormWindowEditor::textDocument()
diff --git a/src/plugins/designer/formwindowfile.cpp b/src/plugins/designer/formwindowfile.cpp
index 9d729c9071a..61b30661fe0 100644
--- a/src/plugins/designer/formwindowfile.cpp
+++ b/src/plugins/designer/formwindowfile.cpp
@@ -41,7 +41,9 @@
 #include <QtDesigner/QDesignerFormWindowInterface>
 #include <QtDesigner/QDesignerFormWindowManagerInterface>
 #include <QtDesigner/QDesignerFormEditorInterface>
-#include "qt_private/qsimpleresource_p.h"
+#if QT_VERSION < 0x050000
+#    include "qt_private/qsimpleresource_p.h"
+#endif
 
 #include <QtGui/QMessageBox>
 #include <QtGui/QMainWindow>
@@ -83,10 +85,13 @@ bool FormWindowFile::save(QString *errorString, const QString &name, bool autoSa
     const QString oldFormName = m_formWindow->fileName();
     if (!autoSave)
         m_formWindow->setFileName(fi.absoluteFilePath());
-
+#if QT_VERSION >= 0x050000
+    const bool writeOK = writeFile(actualName, errorString);
+#else
     const bool warningsEnabled = qdesigner_internal::QSimpleResource::setWarningsEnabled(false);
     const bool writeOK = writeFile(actualName, errorString);
     qdesigner_internal::QSimpleResource::setWarningsEnabled(warningsEnabled);
+#endif
     m_shouldAutoSave = false;
     if (autoSave)
         return writeOK;
diff --git a/src/plugins/designer/qtcreatorintegration.cpp b/src/plugins/designer/qtcreatorintegration.cpp
index f69b657290c..0d8eeb24c55 100644
--- a/src/plugins/designer/qtcreatorintegration.cpp
+++ b/src/plugins/designer/qtcreatorintegration.cpp
@@ -89,12 +89,24 @@ static QString msgClassNotFound(const QString &uiClassName, const QList<Document
 }
 
 QtCreatorIntegration::QtCreatorIntegration(QDesignerFormEditorInterface *core, FormEditorW *parent) :
-    qdesigner_internal::QDesignerIntegration(core, ::qobject_cast<QObject*>(parent)),
+#if QT_VERSION >= 0x050000
+    QDesignerIntegration(core, parent),
+#else
+    qdesigner_internal::QDesignerIntegration(core, parent),
+#endif
     m_few(parent)
 {
+#if QT_VERSION >= 0x050000
+    setResourceFileWatcherBehaviour(ReloadResourceFileSilently);
+    Feature f = features();
+    f |= SlotNavigationFeature;
+    f &= ~ResourceEditorFeature;
+    setFeatures(f);
+#else
     setResourceFileWatcherBehaviour(QDesignerIntegration::ReloadSilently);
     setResourceEditingEnabled(false);
     setSlotNavigationEnabled(true);
+#endif
     connect(this, SIGNAL(navigateToSlot(QString, QString, QStringList)),
             this, SLOT(slotNavigateToSlot(QString, QString, QStringList)));
     connect(this, SIGNAL(helpRequested(QString,QString)),
@@ -115,7 +127,11 @@ void QtCreatorIntegration::updateSelection()
 {
     if (const EditorData ed = m_few->activeEditor())
         ed.widgetHost->updateFormWindowSelectionHandles(true);
+#if QT_VERSION >= 0x050000
+    QDesignerIntegration::updateSelection();
+#else
     qdesigner_internal::QDesignerIntegration::updateSelection();
+#endif
 }
 
 QWidget *QtCreatorIntegration::containerWindow(QWidget * /*widget*/) const
diff --git a/src/plugins/designer/qtcreatorintegration.h b/src/plugins/designer/qtcreatorintegration.h
index 1b4d714ceb2..402056216f4 100644
--- a/src/plugins/designer/qtcreatorintegration.h
+++ b/src/plugins/designer/qtcreatorintegration.h
@@ -35,7 +35,11 @@
 
 #include <cplusplus/ModelManagerInterface.h>
 
-#include "qt_private/qdesigner_integration_p.h"
+#if QT_VERSION >= 0x050000
+#    include <QtDesigner/QDesignerIntegration>
+#else
+#    include "qt_private/qdesigner_integration_p.h"
+#endif
 
 QT_FORWARD_DECLARE_CLASS(QUrl)
 
@@ -44,7 +48,12 @@ namespace Internal {
 
 class FormEditorW;
 
-class QtCreatorIntegration : public qdesigner_internal::QDesignerIntegration {
+class QtCreatorIntegration :
+#if QT_VERSION >= 0x050000
+    public QDesignerIntegration {
+#else
+    public qdesigner_internal::QDesignerIntegration {
+#endif
     Q_OBJECT
 public:
     explicit QtCreatorIntegration(QDesignerFormEditorInterface *core, FormEditorW *parent = 0);
diff --git a/src/plugins/designer/resourcehandler.cpp b/src/plugins/designer/resourcehandler.cpp
index 18a2c057fb6..31ed808332e 100644
--- a/src/plugins/designer/resourcehandler.cpp
+++ b/src/plugins/designer/resourcehandler.cpp
@@ -39,8 +39,12 @@
 #include <projectexplorer/project.h>
 #include <projectexplorer/session.h>
 
-#include "qt_private/formwindowbase_p.h"
-#include "qt_private/qtresourcemodel_p.h"
+#if QT_VERSION >= 0x050000
+#    include <QtDesigner/QDesignerFormWindowInterface>
+#else
+#    include "qt_private/formwindowbase_p.h"
+#    include "qt_private/qtresourcemodel_p.h"
+#endif
 
 #include <utils/qtcassert.h>
 
@@ -83,7 +87,11 @@ void QrcFilesVisitor::visitFolderNode(FolderNode *folderNode)
 }
 
 // ------------ ResourceHandler
+#if QT_VERSION >= 0x050000
+ResourceHandler::ResourceHandler(QDesignerFormWindowInterface *fw) :
+#else
 ResourceHandler::ResourceHandler(qdesigner_internal::FormWindowBase *fw) :
+#endif
     QObject(fw),
     m_form(fw),
     m_sessionNode(0),
@@ -106,8 +114,11 @@ void ResourceHandler::ensureInitialized()
     connect(m_sessionWatcher, SIGNAL(foldersAdded()), this, SLOT(updateResources()));
     connect(m_sessionWatcher, SIGNAL(foldersRemoved()), this, SLOT(updateResources()));
     m_sessionNode->registerWatcher(m_sessionWatcher);
-
+#if QT_VERSION >= 0x050000
+    m_originalUiQrcPaths = m_form->activeResourceFilePaths();
+#else
     m_originalUiQrcPaths = m_form->resourceSet()->activeQrcPaths();
+#endif
     if (Designer::Constants::Internal::debug)
         qDebug() << "ResourceHandler::ensureInitialized() origPaths=" << m_originalUiQrcPaths;
 }
@@ -142,16 +153,26 @@ void ResourceHandler::updateResources()
         QrcFilesVisitor qrcVisitor;
         root->accept(&qrcVisitor);
         const QStringList projectQrcFiles = qrcVisitor.qrcFiles();
+#if QT_VERSION >= 0x050000
+        m_form->activateResourceFilePaths(projectQrcFiles);
+        m_form->setResourceFileSaveMode(QDesignerFormWindowInterface::SaveOnlyUsedResourceFiles);
+#else
         m_form->resourceSet()->activateQrcPaths(projectQrcFiles);
         m_form->setSaveResourcesBehaviour(qdesigner_internal::FormWindowBase::SaveOnlyUsedQrcFiles);
+#endif
         if (Designer::Constants::Internal::debug)
             qDebug() << "ResourceHandler::updateResources()" << fileName
                     << " associated with project" << project->rootProjectNode()->path()
                     <<  " using project qrc files" << projectQrcFiles.size();
     } else {
         // Use resource file originally used in form
+#if QT_VERSION >= 0x050000
+        m_form->activateResourceFilePaths(m_originalUiQrcPaths);
+        m_form->setResourceFileSaveMode(QDesignerFormWindowInterface::SaveAllResourceFiles);
+#else
         m_form->resourceSet()->activateQrcPaths(m_originalUiQrcPaths);
         m_form->setSaveResourcesBehaviour(qdesigner_internal::FormWindowBase::SaveAll);
+#endif
         if (Designer::Constants::Internal::debug)
             qDebug() << "ResourceHandler::updateResources()" << fileName << " not associated with project, using loaded qrc files.";
     }
diff --git a/src/plugins/designer/resourcehandler.h b/src/plugins/designer/resourcehandler.h
index 1fdec7e381f..ec3ca72a9ed 100644
--- a/src/plugins/designer/resourcehandler.h
+++ b/src/plugins/designer/resourcehandler.h
@@ -37,9 +37,13 @@
 #include <QtCore/QStringList>
 
 QT_BEGIN_NAMESPACE
+#if QT_VERSION >= 0x050000
+class QDesignerFormWindowInterface;
+#else
 namespace qdesigner_internal {
     class FormWindowBase;
 }
+#endif
 QT_END_NAMESPACE
 
 namespace ProjectExplorer {
@@ -64,7 +68,11 @@ class ResourceHandler : public QObject
 {
     Q_OBJECT
 public:
-    explicit ResourceHandler(qdesigner_internal::FormWindowBase *fw);
+#if QT_VERSION >= 0x050000
+        explicit ResourceHandler(QDesignerFormWindowInterface *fw);
+#else
+        explicit ResourceHandler(qdesigner_internal::FormWindowBase *fw);
+#endif
     virtual ~ResourceHandler();
 
 public slots:
@@ -72,9 +80,11 @@ public slots:
 
 private:
     void ensureInitialized();
-
+#if QT_VERSION >= 0x050000
+    QDesignerFormWindowInterface * const m_form;
+#else
     qdesigner_internal::FormWindowBase * const m_form;
-
+#endif
     QStringList m_originalUiQrcPaths;
     ProjectExplorer::SessionNode *m_sessionNode;
     ProjectExplorer::NodesWatcher *m_sessionWatcher;
diff --git a/src/plugins/designer/settingsmanager.h b/src/plugins/designer/settingsmanager.h
index d0f0cb1d63a..faf8a21e083 100644
--- a/src/plugins/designer/settingsmanager.h
+++ b/src/plugins/designer/settingsmanager.h
@@ -33,7 +33,11 @@
 #ifndef SETTINGSMANAGER_H
 #define SETTINGSMANAGER_H
 
-#include "qt_private/abstractsettings_p.h"
+#if QT_VERSION >= 0x050000
+#    include <QtDesigner/QDesignerSettingsInterface>
+#else
+#    include "qt_private/abstractsettings_p.h"
+#endif
 
 namespace Designer {
 namespace Internal {
diff --git a/src/plugins/designer/settingspage.cpp b/src/plugins/designer/settingspage.cpp
index f23251dc4ef..a23a5fb712c 100644
--- a/src/plugins/designer/settingspage.cpp
+++ b/src/plugins/designer/settingspage.cpp
@@ -35,7 +35,11 @@
 #include "formeditorw.h"
 
 #include <extensionsystem/pluginmanager.h>
-#include "qt_private/abstractoptionspage_p.h"
+#if QT_VERSION >= 0x050000
+#    include <QtDesigner/QDesignerOptionsPageInterface>
+#else
+#    include "qt_private/abstractoptionspage_p.h"
+#endif
 
 #include <QtCore/QCoreApplication>
 #include <QtGui/QIcon>