diff --git a/CMakeLists.txt b/CMakeLists.txt
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -53,14 +53,6 @@
 set(CMAKE_CXX_STANDARD 14)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
-# This is a workaround/compromise for a Kwin specific policy of not applying the relevant override fix.
-# See thread in D18167.
-if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-inconsistent-missing-override")
-else()
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-suggest-override")
-endif()
-
 find_package(Qt5Multimedia QUIET)
 set_package_properties(Qt5Multimedia PROPERTIES
          PURPOSE "Runtime-only dependency for effect video playback"
diff --git a/abstract_client.h b/abstract_client.h
--- a/abstract_client.h
+++ b/abstract_client.h
@@ -332,7 +332,7 @@
     Q_PROPERTY(QString colorScheme READ colorScheme NOTIFY colorSchemeChanged)
 
 public:
-    virtual ~AbstractClient();
+    ~AbstractClient() override;
 
     QWeakPointer<TabBox::TabBoxClientImpl> tabBoxClient() const {
         return m_tabBoxClient.toWeakRef();
@@ -479,7 +479,7 @@
     int desktop() const override {
         return m_desktops.isEmpty() ? (int)NET::OnAllDesktops : m_desktops.last()->x11DesktopNumber();
     }
-    virtual QVector<VirtualDesktop *> desktops() const {
+    QVector<VirtualDesktop *> desktops() const override {
         return m_desktops;
     }
     QVector<uint> x11DesktopIds() const;
diff --git a/abstract_wayland_output.h b/abstract_wayland_output.h
--- a/abstract_wayland_output.h
+++ b/abstract_wayland_output.h
@@ -57,7 +57,7 @@
     Q_OBJECT
 public:
     explicit AbstractWaylandOutput(QObject *parent = nullptr);
-    virtual ~AbstractWaylandOutput();
+    ~AbstractWaylandOutput() override;
 
     QString name() const override;
     bool isEnabled() const {
diff --git a/activities.h b/activities.h
--- a/activities.h
+++ b/activities.h
@@ -40,7 +40,7 @@
     Q_OBJECT
 
 public:
-    ~Activities();
+    ~Activities() override;
 
     bool stop(const QString &id);
     bool start(const QString &id);
diff --git a/autotests/fakeeffectplugin.cpp b/autotests/fakeeffectplugin.cpp
--- a/autotests/fakeeffectplugin.cpp
+++ b/autotests/fakeeffectplugin.cpp
@@ -27,7 +27,7 @@
     Q_OBJECT
 public:
     FakeEffect() {}
-    virtual ~FakeEffect() {}
+    ~FakeEffect() override {}
 
     static bool supported() {
         return effects->isOpenGLCompositing();
diff --git a/autotests/fakeeffectplugin_version.cpp b/autotests/fakeeffectplugin_version.cpp
--- a/autotests/fakeeffectplugin_version.cpp
+++ b/autotests/fakeeffectplugin_version.cpp
@@ -27,7 +27,7 @@
     Q_OBJECT
 public:
     FakeVersionEffect() {}
-    virtual ~FakeVersionEffect() {}
+    ~FakeVersionEffect() override {}
 };
 
 } // namespace
@@ -39,7 +39,7 @@
     Q_INTERFACES(KPluginFactory)
 public:
     FakeEffectPluginFactory() {}
-    ~FakeEffectPluginFactory() {}
+    ~FakeEffectPluginFactory() override {}
     KWin::Effect *createEffect() const override {
         return new KWin::FakeVersionEffect();
     }
diff --git a/autotests/integration/debug_console_test.cpp b/autotests/integration/debug_console_test.cpp
--- a/autotests/integration/debug_console_test.cpp
+++ b/autotests/integration/debug_console_test.cpp
@@ -413,7 +413,7 @@
     Q_OBJECT
 public:
     HelperWindow() : QRasterWindow(nullptr) {}
-    ~HelperWindow() = default;
+    ~HelperWindow() override = default;
 
 Q_SIGNALS:
     void entered();
diff --git a/autotests/integration/helper/copy.cpp b/autotests/integration/helper/copy.cpp
--- a/autotests/integration/helper/copy.cpp
+++ b/autotests/integration/helper/copy.cpp
@@ -28,7 +28,7 @@
     Q_OBJECT
 public:
     explicit Window();
-    virtual ~Window();
+    ~Window() override;
 
 protected:
     void paintEvent(QPaintEvent *event) override;
diff --git a/autotests/integration/helper/paste.cpp b/autotests/integration/helper/paste.cpp
--- a/autotests/integration/helper/paste.cpp
+++ b/autotests/integration/helper/paste.cpp
@@ -28,7 +28,7 @@
     Q_OBJECT
 public:
     explicit Window();
-    virtual ~Window();
+    ~Window() override;
 
 protected:
     void paintEvent(QPaintEvent *event) override;
diff --git a/autotests/integration/internal_window.cpp b/autotests/integration/internal_window.cpp
--- a/autotests/integration/internal_window.cpp
+++ b/autotests/integration/internal_window.cpp
@@ -84,7 +84,7 @@
     Q_OBJECT
 public:
     HelperWindow();
-    ~HelperWindow();
+    ~HelperWindow() override;
 
     QPoint latestGlobalMousePos() const {
         return m_latestGlobalMousePos;
diff --git a/autotests/integration/kwin_wayland_test.h b/autotests/integration/kwin_wayland_test.h
--- a/autotests/integration/kwin_wayland_test.h
+++ b/autotests/integration/kwin_wayland_test.h
@@ -67,7 +67,7 @@
     Q_OBJECT
 public:
     WaylandTestApplication(OperationMode mode, int &argc, char **argv);
-    virtual ~WaylandTestApplication();
+    ~WaylandTestApplication() override;
 
 protected:
     void performStartup() override;
diff --git a/autotests/integration/lockscreen.cpp b/autotests/integration/lockscreen.cpp
--- a/autotests/integration/lockscreen.cpp
+++ b/autotests/integration/lockscreen.cpp
@@ -93,7 +93,7 @@
     Q_OBJECT
 public:
     HelperEffect() {}
-    ~HelperEffect() {}
+    ~HelperEffect() override {}
 
     void windowInputMouseEvent(QEvent*) override {
         emit inputEvent();
diff --git a/autotests/integration/modifier_only_shortcut_test.cpp b/autotests/integration/modifier_only_shortcut_test.cpp
--- a/autotests/integration/modifier_only_shortcut_test.cpp
+++ b/autotests/integration/modifier_only_shortcut_test.cpp
@@ -61,7 +61,7 @@
 
 public:
     Target();
-    virtual ~Target();
+    ~Target() override;
 
 public Q_SLOTS:
     Q_SCRIPTABLE void shortcut();
diff --git a/autotests/integration/no_global_shortcuts_test.cpp b/autotests/integration/no_global_shortcuts_test.cpp
--- a/autotests/integration/no_global_shortcuts_test.cpp
+++ b/autotests/integration/no_global_shortcuts_test.cpp
@@ -70,7 +70,7 @@
 
 public:
     Target();
-    virtual ~Target();
+    ~Target() override;
 
 public Q_SLOTS:
     Q_SCRIPTABLE void shortcut();
diff --git a/autotests/integration/plasmawindow_test.cpp b/autotests/integration/plasmawindow_test.cpp
--- a/autotests/integration/plasmawindow_test.cpp
+++ b/autotests/integration/plasmawindow_test.cpp
@@ -207,7 +207,7 @@
     Q_OBJECT
 public:
     HelperWindow();
-    ~HelperWindow();
+    ~HelperWindow() override;
 
 protected:
     void paintEvent(QPaintEvent *event) override;
diff --git a/autotests/integration/pointer_input.cpp b/autotests/integration/pointer_input.cpp
--- a/autotests/integration/pointer_input.cpp
+++ b/autotests/integration/pointer_input.cpp
@@ -1079,7 +1079,7 @@
     Q_OBJECT
 public:
     HelperEffect() {}
-    ~HelperEffect() {}
+    ~HelperEffect() override {}
 };
 
 void PointerInputTest::testEffectOverrideCursorImage()
diff --git a/autotests/mock_abstract_client.h b/autotests/mock_abstract_client.h
--- a/autotests/mock_abstract_client.h
+++ b/autotests/mock_abstract_client.h
@@ -31,7 +31,7 @@
     Q_OBJECT
 public:
     explicit AbstractClient(QObject *parent);
-    virtual ~AbstractClient();
+    ~AbstractClient() override;
 
     int screen() const;
     bool isOnScreen(int screen) const;
diff --git a/autotests/mock_client.h b/autotests/mock_client.h
--- a/autotests/mock_client.h
+++ b/autotests/mock_client.h
@@ -33,7 +33,7 @@
     Q_OBJECT
 public:
     explicit Client(QObject *parent);
-    virtual ~Client();
+    ~Client() override;
     void showOnScreenEdge() override;
 
 };
diff --git a/autotests/mock_effectshandler.h b/autotests/mock_effectshandler.h
--- a/autotests/mock_effectshandler.h
+++ b/autotests/mock_effectshandler.h
@@ -29,7 +29,7 @@
 public:
     explicit MockEffectsHandler(KWin::CompositingType type);
     void activateWindow(KWin::EffectWindow *) override {}
-    KWin::Effect *activeFullScreenEffect() const {
+    KWin::Effect *activeFullScreenEffect() const override {
         return nullptr;
     }
     bool hasActiveFullScreenEffect() const override {
@@ -271,7 +271,7 @@
     }
     void hideOnScreenMessage(OnScreenMessageHideFlags flags = OnScreenMessageHideFlags()) override { Q_UNUSED(flags)}
 
-    void windowToDesktops(KWin::EffectWindow *w, const QVector<uint> &desktops) {
+    void windowToDesktops(KWin::EffectWindow *w, const QVector<uint> &desktops) override {
         Q_UNUSED(w)
         Q_UNUSED(desktops)
     }
diff --git a/autotests/mock_screens.h b/autotests/mock_screens.h
--- a/autotests/mock_screens.h
+++ b/autotests/mock_screens.h
@@ -30,7 +30,7 @@
     Q_OBJECT
 public:
     explicit MockScreens(QObject *parent = nullptr);
-    virtual ~MockScreens();
+    ~MockScreens() override;
     QRect geometry(int screen) const override;
     int number(const QPoint &pos) const override;
     QString name(int screen) const override;
diff --git a/autotests/mock_workspace.h b/autotests/mock_workspace.h
--- a/autotests/mock_workspace.h
+++ b/autotests/mock_workspace.h
@@ -38,7 +38,7 @@
     Q_OBJECT
 public:
     explicit MockWorkspace(QObject *parent = nullptr);
-    virtual ~MockWorkspace();
+    ~MockWorkspace() override;
     AbstractClient *activeClient() const;
     AbstractClient *moveResizeClient() const;
     void setShowingDesktop(bool showing);
diff --git a/autotests/tabbox/mock_tabboxclient.h b/autotests/tabbox/mock_tabboxclient.h
--- a/autotests/tabbox/mock_tabboxclient.h
+++ b/autotests/tabbox/mock_tabboxclient.h
@@ -31,38 +31,38 @@
 {
 public:
     explicit MockTabBoxClient(QString caption, WId id);
-    virtual bool isMinimized() const {
+    bool isMinimized() const override {
         return false;
     }
-    virtual QString caption() const {
+    QString caption() const override {
         return m_caption;
     }
-    virtual void close();
-    virtual int height() const {
+    void close() override;
+    int height() const override {
         return 100;
     }
     virtual QPixmap icon(const QSize &size = QSize(32, 32)) const {
         return QPixmap(size);
     }
-    virtual bool isCloseable() const {
+    bool isCloseable() const override {
         return true;
     }
-    virtual bool isFirstInTabBox() const {
+    bool isFirstInTabBox() const override {
         return false;
     }
-    virtual int width() const {
+    int width() const override {
         return 100;
     }
-    virtual WId window() const {
+    WId window() const override {
         return m_wId;
     }
-    virtual int x() const {
+    int x() const override {
         return 0;
     }
-    virtual int y() const {
+    int y() const override {
         return 0;
     }
-    virtual QIcon icon() const {
+    QIcon icon() const override {
         return QIcon();
     }
 
diff --git a/autotests/tabbox/mock_tabboxhandler.h b/autotests/tabbox/mock_tabboxhandler.h
--- a/autotests/tabbox/mock_tabboxhandler.h
+++ b/autotests/tabbox/mock_tabboxhandler.h
@@ -28,70 +28,70 @@
     Q_OBJECT
 public:
     MockTabBoxHandler(QObject *parent = nullptr);
-    virtual ~MockTabBoxHandler();
-    virtual void activateAndClose() {
+    ~MockTabBoxHandler() override;
+    void activateAndClose() override {
     }
-    virtual QWeakPointer< TabBox::TabBoxClient > activeClient() const;
+    QWeakPointer< TabBox::TabBoxClient > activeClient() const override;
     void setActiveClient(const QWeakPointer<TabBox::TabBoxClient> &client);
-    virtual int activeScreen() const {
+    int activeScreen() const override {
         return 0;
     }
-    virtual QWeakPointer< TabBox::TabBoxClient > clientToAddToList(TabBox::TabBoxClient *client, int desktop) const;
-    virtual int currentDesktop() const {
+    QWeakPointer< TabBox::TabBoxClient > clientToAddToList(TabBox::TabBoxClient *client, int desktop) const override;
+    int currentDesktop() const override {
         return 1;
     }
-    virtual QWeakPointer< TabBox::TabBoxClient > desktopClient() const {
+    QWeakPointer< TabBox::TabBoxClient > desktopClient() const override {
         return QWeakPointer<TabBox::TabBoxClient>();
     }
-    virtual QString desktopName(int desktop) const {
+    QString desktopName(int desktop) const override {
         Q_UNUSED(desktop)
         return "desktop 1";
     }
-    virtual QString desktopName(TabBox::TabBoxClient *client) const {
+    QString desktopName(TabBox::TabBoxClient *client) const override {
         Q_UNUSED(client)
         return "desktop";
     }
-    virtual void elevateClient(TabBox::TabBoxClient *c, QWindow *tabbox, bool elevate) const {
+    void elevateClient(TabBox::TabBoxClient *c, QWindow *tabbox, bool elevate) const override {
         Q_UNUSED(c)
         Q_UNUSED(tabbox)
         Q_UNUSED(elevate)
     }
-    virtual void shadeClient(TabBox::TabBoxClient *c, bool b) const {
+    void shadeClient(TabBox::TabBoxClient *c, bool b) const override {
         Q_UNUSED(c)
         Q_UNUSED(b)
     }
     virtual void hideOutline() {
     }
-    virtual QWeakPointer< TabBox::TabBoxClient > nextClientFocusChain(TabBox::TabBoxClient *client) const;
-    virtual QWeakPointer<TabBox::TabBoxClient> firstClientFocusChain() const;
-    virtual bool isInFocusChain (TabBox::TabBoxClient* client) const;
-    virtual int nextDesktopFocusChain(int desktop) const {
+    QWeakPointer< TabBox::TabBoxClient > nextClientFocusChain(TabBox::TabBoxClient *client) const override;
+    QWeakPointer<TabBox::TabBoxClient> firstClientFocusChain() const override;
+    bool isInFocusChain (TabBox::TabBoxClient* client) const override;
+    int nextDesktopFocusChain(int desktop) const override {
         Q_UNUSED(desktop)
         return 1;
     }
-    virtual int numberOfDesktops() const {
+    int numberOfDesktops() const override {
         return 1;
     }
     virtual QVector< xcb_window_t > outlineWindowIds() const {
         return QVector<xcb_window_t>();
     }
-    virtual bool isKWinCompositing() const {
+    bool isKWinCompositing() const override {
         return false;
     }
-    virtual void raiseClient(TabBox::TabBoxClient *c) const {
+    void raiseClient(TabBox::TabBoxClient *c) const override {
         Q_UNUSED(c)
     }
-    virtual void restack(TabBox::TabBoxClient *c, TabBox::TabBoxClient *under) {
+    void restack(TabBox::TabBoxClient *c, TabBox::TabBoxClient *under) override {
         Q_UNUSED(c)
         Q_UNUSED(under)
     }
     virtual void showOutline(const QRect &outline) {
         Q_UNUSED(outline)
     }
-    virtual TabBox::TabBoxClientList stackingOrder() const {
+    TabBox::TabBoxClientList stackingOrder() const override {
         return TabBox::TabBoxClientList();
     }
-    virtual void grabbedKeyEvent(QKeyEvent *event) const;
+    void grabbedKeyEvent(QKeyEvent *event) const override;
 
     void highlightWindows(TabBox::TabBoxClient *window = nullptr, QWindow *controller = nullptr) override {
         Q_UNUSED(window)
diff --git a/autotests/test_virtualkeyboard_dbus.cpp b/autotests/test_virtualkeyboard_dbus.cpp
--- a/autotests/test_virtualkeyboard_dbus.cpp
+++ b/autotests/test_virtualkeyboard_dbus.cpp
@@ -52,7 +52,7 @@
             this,
             SLOT(slotEnabledChanged()));
     }
-    ~DbusPropertyHelper() = default;
+    ~DbusPropertyHelper() override = default;
 
 Q_SIGNALS:
     void enabledChanged();
diff --git a/autotests/test_x11_timestamp_update.cpp b/autotests/test_x11_timestamp_update.cpp
--- a/autotests/test_x11_timestamp_update.cpp
+++ b/autotests/test_x11_timestamp_update.cpp
@@ -35,7 +35,7 @@
     Q_OBJECT
 public:
     X11TestApplication(int &argc, char **argv);
-    virtual ~X11TestApplication();
+    ~X11TestApplication() override;
 
 protected:
     void performStartup() override;
diff --git a/client.h b/client.h
--- a/client.h
+++ b/client.h
@@ -90,7 +90,7 @@
     explicit Client();
     xcb_window_t wrapperId() const;
     xcb_window_t inputId() const { return m_decoInputExtent; }
-    virtual xcb_window_t frameId() const override;
+    xcb_window_t frameId() const override;
 
     bool isTransient() const override;
     bool groupTransient() const override;
@@ -111,17 +111,17 @@
     QSize minSize() const override;
     QSize maxSize() const override;
     QSize basicUnit() const;
-    virtual QSize clientSize() const;
+    QSize clientSize() const override;
     QPoint inputPos() const { return input_offset; } // Inside of geometry()
 
     bool windowEvent(xcb_generic_event_t *e);
-    NET::WindowType windowType(bool direct = false, int supported_types = 0) const;
+    NET::WindowType windowType(bool direct = false, int supported_types = 0) const override;
 
     bool manage(xcb_window_t w, bool isMapped);
     void releaseWindow(bool on_shutdown = false);
     void destroyClient();
 
-    virtual QStringList activities() const;
+    QStringList activities() const override;
     void setOnActivity(const QString &activity, bool enable);
     void setOnAllActivities(bool set) override;
     void setOnActivities(QStringList newActivitiesList) override;
@@ -203,7 +203,7 @@
     void hideClient(bool hide) override;
     bool hiddenPreview() const; ///< Window is mapped in order to get a window pixmap
 
-    virtual bool setupCompositing();
+    bool setupCompositing() override;
     void finishCompositing(ReleaseReason releaseReason = ReleaseReason::Release) override;
     void setBlockingCompositing(bool block);
     inline bool isBlockingCompositing() { return blocks_compositing; }
@@ -263,9 +263,9 @@
     bool hasOffscreenXineramaStrut() const;
 
     // Decorations <-> Effects
-    QRect decorationRect() const;
+    QRect decorationRect() const override;
 
-    QRect transparentRect() const;
+    QRect transparentRect() const override;
 
     bool isClientSideDecorated() const;
     bool wantsShadowToBeRendered() const override;
@@ -281,7 +281,7 @@
 
     //sets whether the client should be faked as being on all activities (and be shown during session save)
     void setSessionActivityOverride(bool needed);
-    virtual bool isClient() const;
+    bool isClient() const override;
 
     template <typename T>
     void print(T &stream) const;
@@ -327,29 +327,29 @@
 
 private:
     // Use Workspace::createClient()
-    virtual ~Client(); ///< Use destroyClient() or releaseWindow()
+    ~Client() override; ///< Use destroyClient() or releaseWindow()
 
     // Handlers for X11 events
     bool mapRequestEvent(xcb_map_request_event_t *e);
     void unmapNotifyEvent(xcb_unmap_notify_event_t *e);
     void destroyNotifyEvent(xcb_destroy_notify_event_t *e);
     void configureRequestEvent(xcb_configure_request_event_t *e);
-    virtual void propertyNotifyEvent(xcb_property_notify_event_t *e) override;
+    void propertyNotifyEvent(xcb_property_notify_event_t *e) override;
     void clientMessageEvent(xcb_client_message_event_t *e) override;
     void enterNotifyEvent(xcb_enter_notify_event_t *e);
     void leaveNotifyEvent(xcb_leave_notify_event_t *e);
     void focusInEvent(xcb_focus_in_event_t *e);
     void focusOutEvent(xcb_focus_out_event_t *e);
-    virtual void damageNotifyEvent();
+    void damageNotifyEvent() override;
 
     bool buttonPressEvent(xcb_window_t w, int button, int state, int x, int y, int x_root, int y_root, xcb_timestamp_t time = XCB_CURRENT_TIME);
     bool buttonReleaseEvent(xcb_window_t w, int button, int state, int x, int y, int x_root, int y_root);
     bool motionNotifyEvent(xcb_window_t w, int state, int x, int y, int x_root, int y_root);
 
     Client* findAutogroupCandidate() const;
 
 protected:
-    virtual void debug(QDebug& stream) const;
+    void debug(QDebug& stream) const override;
     void addDamage(const QRegion &damage) override;
     bool belongsToSameApplication(const AbstractClient *other, SameApplicationChecks checks) const override;
     void doSetActive() override;
diff --git a/client_machine.h b/client_machine.h
--- a/client_machine.h
+++ b/client_machine.h
@@ -35,7 +35,7 @@
     Q_OBJECT
 public:
     explicit GetAddrInfo(const QByteArray &hostName, QObject *parent = NULL);
-    virtual ~GetAddrInfo();
+    ~GetAddrInfo() override;
 
     void resolve();
 
@@ -65,7 +65,7 @@
     Q_OBJECT
 public:
     explicit ClientMachine(QObject *parent = NULL);
-    virtual ~ClientMachine();
+    ~ClientMachine() override;
 
     void resolve(xcb_window_t window, xcb_window_t clientLeader);
     const QByteArray &hostName() const;
diff --git a/colorcorrection/colorcorrectdbusinterface.h b/colorcorrection/colorcorrectdbusinterface.h
--- a/colorcorrection/colorcorrectdbusinterface.h
+++ b/colorcorrection/colorcorrectdbusinterface.h
@@ -39,7 +39,7 @@
 
 public:
     explicit ColorCorrectDBusInterface(Manager *parent);
-    virtual ~ColorCorrectDBusInterface() = default;
+    ~ColorCorrectDBusInterface() override = default;
 
 public Q_SLOTS:
     /**
diff --git a/cursor.h b/cursor.h
--- a/cursor.h
+++ b/cursor.h
@@ -97,7 +97,7 @@
 {
     Q_OBJECT
 public:
-    virtual ~Cursor();
+    ~Cursor() override;
     void startMousePolling();
     void stopMousePolling();
     /**
@@ -258,11 +258,11 @@
     Q_OBJECT
 public:
     explicit InputRedirectionCursor(QObject *parent);
-    virtual ~InputRedirectionCursor();
+    ~InputRedirectionCursor() override;
 protected:
-    virtual void doSetPos();
-    virtual void doStartCursorTracking();
-    virtual void doStopCursorTracking();
+    void doSetPos() override;
+    void doStartCursorTracking() override;
+    void doStopCursorTracking() override;
 private Q_SLOTS:
     void slotPosChanged(const QPointF &pos);
     void slotPointerButtonChanged();
diff --git a/dbusinterface.h b/dbusinterface.h
--- a/dbusinterface.h
+++ b/dbusinterface.h
@@ -52,7 +52,7 @@
     Q_CLASSINFO("D-Bus Interface", "org.kde.KWin")
 public:
     explicit DBusInterface(QObject *parent);
-    virtual ~DBusInterface();
+    ~DBusInterface() override;
 
 public: // PROPERTIES
 public Q_SLOTS: // METHODS
@@ -125,7 +125,7 @@
     Q_PROPERTY(bool platformRequiresCompositing READ platformRequiresCompositing)
 public:
     explicit CompositorDBusInterface(Compositor *parent);
-    virtual ~CompositorDBusInterface() = default;
+    ~CompositorDBusInterface() override = default;
 
     bool isActive() const;
     bool isCompositingPossible() const;
@@ -211,7 +211,7 @@
 
 public:
     VirtualDesktopManagerDBusInterface(VirtualDesktopManager *parent);
-    ~VirtualDesktopManagerDBusInterface() = default;
+    ~VirtualDesktopManagerDBusInterface() override = default;
 
     uint count() const;
 
diff --git a/debug_console.h b/debug_console.h
--- a/debug_console.h
+++ b/debug_console.h
@@ -49,7 +49,7 @@
     Q_OBJECT
 public:
     explicit DebugConsoleModel(QObject *parent = nullptr);
-    virtual ~DebugConsoleModel();
+    ~DebugConsoleModel() override;
 
 
     int columnCount(const QModelIndex &parent) const override;
@@ -90,7 +90,7 @@
     Q_OBJECT
 public:
     explicit DebugConsoleDelegate(QObject *parent = nullptr);
-    virtual ~DebugConsoleDelegate();
+    ~DebugConsoleDelegate() override;
 
     QString displayText(const QVariant &value, const QLocale &locale) const override;
 };
@@ -100,7 +100,7 @@
     Q_OBJECT
 public:
     DebugConsole();
-    virtual ~DebugConsole();
+    ~DebugConsole() override;
 
 protected:
     void showEvent(QShowEvent *event) override;
@@ -118,7 +118,7 @@
     Q_OBJECT
 public:
     explicit SurfaceTreeModel(QObject *parent = nullptr);
-    virtual ~SurfaceTreeModel();
+    ~SurfaceTreeModel() override;
 
     int columnCount(const QModelIndex &parent) const override;
     QVariant data(const QModelIndex &index, int role) const override;
@@ -131,7 +131,7 @@
 {
 public:
     explicit DebugConsoleFilter(QTextEdit *textEdit);
-    virtual ~DebugConsoleFilter();
+    ~DebugConsoleFilter() override;
 
     void pointerEvent(MouseEvent *event) override;
     void wheelEvent(WheelEvent *event) override;
@@ -166,7 +166,7 @@
     Q_OBJECT
 public:
     explicit InputDeviceModel(QObject *parent = nullptr);
-    virtual ~InputDeviceModel();
+    ~InputDeviceModel() override;
 
     int columnCount(const QModelIndex &parent) const override;
     QVariant data(const QModelIndex &index, int role) const override;
diff --git a/decorations/decoratedclient.h b/decorations/decoratedclient.h
--- a/decorations/decoratedclient.h
+++ b/decorations/decoratedclient.h
@@ -42,7 +42,7 @@
     Q_OBJECT
 public:
     explicit DecoratedClientImpl(AbstractClient *client, KDecoration2::DecoratedClient *decoratedClient, KDecoration2::Decoration *decoration);
-    virtual ~DecoratedClientImpl();
+    ~DecoratedClientImpl() override;
     QString caption() const override;
     WId decorationId() const override;
     int desktop() const override;
@@ -87,7 +87,7 @@
     void requestToggleOnAllDesktops() override;
     void requestToggleShade() override;
 
-    void showApplicationMenu(int actionId);
+    void showApplicationMenu(int actionId) override;
 
     AbstractClient *client() {
         return m_client;
diff --git a/decorations/decorationbridge.h b/decorations/decorationbridge.h
--- a/decorations/decorationbridge.h
+++ b/decorations/decorationbridge.h
@@ -48,7 +48,7 @@
 {
     Q_OBJECT
 public:
-    virtual ~DecorationBridge();
+    ~DecorationBridge() override;
 
     void init();
     KDecoration2::Decoration *createDecoration(AbstractClient *client);
diff --git a/decorations/decorationrenderer.h b/decorations/decorationrenderer.h
--- a/decorations/decorationrenderer.h
+++ b/decorations/decorationrenderer.h
@@ -39,7 +39,7 @@
 {
     Q_OBJECT
 public:
-    virtual ~Renderer();
+    ~Renderer() override;
 
     void schedule(const QRect &rect);
 
diff --git a/decorations/settings.h b/decorations/settings.h
--- a/decorations/settings.h
+++ b/decorations/settings.h
@@ -36,7 +36,7 @@
     Q_OBJECT
 public:
     explicit SettingsImpl(KDecoration2::DecorationSettings *parent);
-    virtual ~SettingsImpl();
+    ~SettingsImpl() override;
     bool isAlphaChannelSupported() const override;
     bool isOnAllDesktopsAvailable() const override;
     bool isCloseOnDoubleClickOnMenu() const override;
diff --git a/deleted.h b/deleted.h
--- a/deleted.h
+++ b/deleted.h
@@ -44,23 +44,23 @@
     void refWindow();
     void unrefWindow();
     void discard();
-    virtual int desktop() const;
-    virtual QStringList activities() const;
-    virtual QVector<VirtualDesktop *> desktops() const;
-    virtual QPoint clientPos() const;
-    virtual QSize clientSize() const;
+    int desktop() const override;
+    QStringList activities() const override;
+    QVector<VirtualDesktop *> desktops() const override;
+    QPoint clientPos() const override;
+    QSize clientSize() const override;
     QPoint clientContentPos() const override {
         return m_contentPos;
     }
-    virtual QRect transparentRect() const;
-    virtual bool isDeleted() const;
-    virtual xcb_window_t frameId() const override;
+    QRect transparentRect() const override;
+    bool isDeleted() const override;
+    xcb_window_t frameId() const override;
     bool noBorder() const {
         return no_border;
     }
     void layoutDecorationRects(QRect &left, QRect &top, QRect &right, QRect &bottom) const;
-    QRect decorationRect() const;
-    virtual Layer layer() const {
+    QRect decorationRect() const override;
+    Layer layer() const override {
         return m_layer;
     }
     bool isMinimized() const {
@@ -72,7 +72,7 @@
     QList<AbstractClient*> mainClients() const {
         return m_mainClients;
     }
-    NET::WindowType windowType(bool direct = false, int supported_types = 0) const;
+    NET::WindowType windowType(bool direct = false, int supported_types = 0) const override;
     bool wasClient() const {
         return m_wasClient;
     }
@@ -185,16 +185,16 @@
     }
 
 protected:
-    virtual void debug(QDebug& stream) const;
+    void debug(QDebug& stream) const override;
 
 private Q_SLOTS:
     void mainClientClosed(KWin::Toplevel *client);
     void transientForClosed(Toplevel *toplevel, Deleted *deleted);
 
 private:
     Deleted();   // use create()
     void copyToDeleted(Toplevel* c);
-    virtual ~Deleted(); // deleted only using unrefWindow()
+    ~Deleted() override; // deleted only using unrefWindow()
 
     void addTransient(Deleted *transient);
     void removeTransient(Deleted *transient);
diff --git a/effectloader.h b/effectloader.h
--- a/effectloader.h
+++ b/effectloader.h
@@ -70,7 +70,7 @@
 {
     Q_OBJECT
 public:
-    virtual ~AbstractEffectLoader();
+    ~AbstractEffectLoader() override;
 
     /**
      * @brief The KSharedConfig this EffectLoader should operate on.
diff --git a/effects.h b/effects.h
--- a/effects.h
+++ b/effects.h
@@ -72,7 +72,7 @@
     Q_PROPERTY(QStringList listOfEffects READ listOfEffects)
 public:
     EffectsHandlerImpl(Compositor *compositor, Scene *scene);
-    virtual ~EffectsHandlerImpl();
+    ~EffectsHandlerImpl() override;
     void prePaintScreen(ScreenPrePaintData& data, int time) override;
     void paintScreen(int mask, QRegion region, ScreenPaintData& data) override;
     /**
@@ -262,7 +262,7 @@
         return registered_atoms.contains(atom);
     }
 
-    void windowToDesktops(EffectWindow *w, const QVector<uint> &desktops);
+    void windowToDesktops(EffectWindow *w, const QVector<uint> &desktops) override;
 
     /**
      * Finds an effect with the given name.
@@ -490,8 +490,8 @@
 
     void elevate(bool elevate);
 
-    void setData(int role, const QVariant &data);
-    QVariant data(int role) const;
+    void setData(int role, const QVariant &data) override;
+    QVariant data(int role) const override;
 
     void registerThumbnail(AbstractThumbnailItem *item);
     QHash<WindowThumbnailItem*, QWeakPointer<EffectWindowImpl> > const &thumbnails() const {
@@ -534,7 +534,7 @@
 public:
     explicit EffectFrameImpl(EffectFrameStyle style, bool staticSize = true, QPoint position = QPoint(-1, -1),
                              Qt::Alignment alignment = Qt::AlignCenter);
-    virtual ~EffectFrameImpl();
+    ~EffectFrameImpl() override;
 
     void free() override;
     void render(QRegion region = infiniteRegion(), double opacity = 1.0, double frameOpacity = 1.0) override;
diff --git a/effects/blur/blur_config.h b/effects/blur/blur_config.h
--- a/effects/blur/blur_config.h
+++ b/effects/blur/blur_config.h
@@ -32,9 +32,9 @@
 
 public:
     explicit BlurEffectConfig(QWidget *parent = 0, const QVariantList& args = QVariantList());
-    ~BlurEffectConfig();
+    ~BlurEffectConfig() override;
 
-    void save();
+    void save() override;
 
 private:
     ::Ui::BlurEffectConfig ui;
diff --git a/effects/colorpicker/colorpicker.h b/effects/colorpicker/colorpicker.h
--- a/effects/colorpicker/colorpicker.h
+++ b/effects/colorpicker/colorpicker.h
@@ -36,7 +36,7 @@
     Q_CLASSINFO("D-Bus Interface", "org.kde.kwin.ColorPicker")
 public:
     ColorPickerEffect();
-    virtual ~ColorPickerEffect();
+    ~ColorPickerEffect() override;
     void paintScreen(int mask, QRegion region, ScreenPaintData &data) override;
     void postPaintScreen() override;
     bool isActive() const override;
diff --git a/effects/coverswitch/coverswitch.h b/effects/coverswitch/coverswitch.h
--- a/effects/coverswitch/coverswitch.h
+++ b/effects/coverswitch/coverswitch.h
@@ -55,7 +55,7 @@
     void reconfigure(ReconfigureFlags) override;
     void prePaintScreen(ScreenPrePaintData &data, int time) override;
     void paintScreen(int mask, QRegion region, ScreenPaintData &data) override;
-    void postPaintScreen();
+    void postPaintScreen() override;
     void paintWindow(EffectWindow *w, int mask, QRegion region, WindowPaintData &data) override;
     void windowInputMouseEvent(QEvent *e) override;
     bool isActive() const override;
diff --git a/effects/coverswitch/coverswitch_config.h b/effects/coverswitch/coverswitch_config.h
--- a/effects/coverswitch/coverswitch_config.h
+++ b/effects/coverswitch/coverswitch_config.h
@@ -43,7 +43,7 @@
     explicit CoverSwitchEffectConfig(QWidget* parent = 0, const QVariantList& args = QVariantList());
 
 public Q_SLOTS:
-    virtual void save();
+    void save() override;
 
 private:
     CoverSwitchEffectConfigForm* m_ui;
diff --git a/effects/cube/cube.h b/effects/cube/cube.h
--- a/effects/cube/cube.h
+++ b/effects/cube/cube.h
@@ -56,24 +56,24 @@
     // TODO: electric borders: not a registered type
 public:
     CubeEffect();
-    ~CubeEffect();
-    virtual void reconfigure(ReconfigureFlags);
-    virtual void prePaintScreen(ScreenPrePaintData& data, int time);
-    virtual void paintScreen(int mask, QRegion region, ScreenPaintData& data);
-    virtual void postPaintScreen();
-    virtual void prePaintWindow(EffectWindow* w, WindowPrePaintData& data, int time);
-    virtual void paintWindow(EffectWindow* w, int mask, QRegion region, WindowPaintData& data);
-    virtual bool borderActivated(ElectricBorder border);
-    virtual void grabbedKeyboardEvent(QKeyEvent* e);
-    virtual void windowInputMouseEvent(QEvent* e);
-    virtual bool isActive() const;
+    ~CubeEffect() override;
+    void reconfigure(ReconfigureFlags) override;
+    void prePaintScreen(ScreenPrePaintData& data, int time) override;
+    void paintScreen(int mask, QRegion region, ScreenPaintData& data) override;
+    void postPaintScreen() override;
+    void prePaintWindow(EffectWindow* w, WindowPrePaintData& data, int time) override;
+    void paintWindow(EffectWindow* w, int mask, QRegion region, WindowPaintData& data) override;
+    bool borderActivated(ElectricBorder border) override;
+    void grabbedKeyboardEvent(QKeyEvent* e) override;
+    void windowInputMouseEvent(QEvent* e) override;
+    bool isActive() const override;
 
     int requestedEffectChainPosition() const override {
         return 50;
     }
 
     // proxy functions
-    virtual void* proxy();
+    void* proxy() override;
     void registerCubeInsideEffect(CubeInsideEffect* effect);
     void unregisterCubeInsideEffect(CubeInsideEffect* effect);
 
diff --git a/effects/cube/cube_config.h b/effects/cube/cube_config.h
--- a/effects/cube/cube_config.h
+++ b/effects/cube/cube_config.h
@@ -43,7 +43,7 @@
     explicit CubeEffectConfig(QWidget* parent = 0, const QVariantList& args = QVariantList());
 
 public Q_SLOTS:
-    virtual void save();
+    void save() override;
 
 private Q_SLOTS:
     void capsSelectionChanged();
diff --git a/effects/cube/cube_inside.h b/effects/cube/cube_inside.h
--- a/effects/cube/cube_inside.h
+++ b/effects/cube/cube_inside.h
@@ -29,7 +29,7 @@
 {
 public:
     CubeInsideEffect() {}
-    virtual ~CubeInsideEffect() {}
+    ~CubeInsideEffect() override {}
 
     virtual void paint() = 0;
     virtual void setActive(bool active) = 0;
diff --git a/effects/cubeslide/cubeslide.h b/effects/cubeslide/cubeslide.h
--- a/effects/cubeslide/cubeslide.h
+++ b/effects/cubeslide/cubeslide.h
@@ -40,14 +40,14 @@
     Q_PROPERTY(bool useWindowMoving READ isUseWindowMoving)
 public:
     CubeSlideEffect();
-    ~CubeSlideEffect();
-    virtual void reconfigure(ReconfigureFlags);
-    virtual void prePaintScreen(ScreenPrePaintData& data, int time);
-    virtual void paintScreen(int mask, QRegion region, ScreenPaintData& data);
-    virtual void postPaintScreen();
-    virtual void prePaintWindow(EffectWindow* w, WindowPrePaintData& data, int time);
-    virtual void paintWindow(EffectWindow* w, int mask, QRegion region, WindowPaintData& data);
-    virtual bool isActive() const;
+    ~CubeSlideEffect() override;
+    void reconfigure(ReconfigureFlags) override;
+    void prePaintScreen(ScreenPrePaintData& data, int time) override;
+    void paintScreen(int mask, QRegion region, ScreenPaintData& data) override;
+    void postPaintScreen() override;
+    void prePaintWindow(EffectWindow* w, WindowPrePaintData& data, int time) override;
+    void paintWindow(EffectWindow* w, int mask, QRegion region, WindowPaintData& data) override;
+    bool isActive() const override;
 
     int requestedEffectChainPosition() const override {
         return 50;
diff --git a/effects/cubeslide/cubeslide_config.h b/effects/cubeslide/cubeslide_config.h
--- a/effects/cubeslide/cubeslide_config.h
+++ b/effects/cubeslide/cubeslide_config.h
@@ -43,7 +43,7 @@
     explicit CubeSlideEffectConfig(QWidget* parent = 0, const QVariantList& args = QVariantList());
 
 public Q_SLOTS:
-    virtual void save();
+    void save() override;
 
 private:
     CubeSlideEffectConfigForm* m_ui;
diff --git a/effects/desktopgrid/desktopgrid.h b/effects/desktopgrid/desktopgrid.h
--- a/effects/desktopgrid/desktopgrid.h
+++ b/effects/desktopgrid/desktopgrid.h
@@ -67,17 +67,17 @@
     // TODO: electric borders
 public:
     DesktopGridEffect();
-    ~DesktopGridEffect();
-    virtual void reconfigure(ReconfigureFlags);
-    virtual void prePaintScreen(ScreenPrePaintData& data, int time);
-    virtual void paintScreen(int mask, QRegion region, ScreenPaintData& data);
-    virtual void postPaintScreen();
-    virtual void prePaintWindow(EffectWindow* w, WindowPrePaintData& data, int time);
-    virtual void paintWindow(EffectWindow* w, int mask, QRegion region, WindowPaintData& data);
-    virtual void windowInputMouseEvent(QEvent* e);
-    virtual void grabbedKeyboardEvent(QKeyEvent* e);
-    virtual bool borderActivated(ElectricBorder border);
-    virtual bool isActive() const;
+    ~DesktopGridEffect() override;
+    void reconfigure(ReconfigureFlags) override;
+    void prePaintScreen(ScreenPrePaintData& data, int time) override;
+    void paintScreen(int mask, QRegion region, ScreenPaintData& data) override;
+    void postPaintScreen() override;
+    void prePaintWindow(EffectWindow* w, WindowPrePaintData& data, int time) override;
+    void paintWindow(EffectWindow* w, int mask, QRegion region, WindowPaintData& data) override;
+    void windowInputMouseEvent(QEvent* e) override;
+    void grabbedKeyboardEvent(QKeyEvent* e) override;
+    bool borderActivated(ElectricBorder border) override;
+    bool isActive() const override;
 
     int requestedEffectChainPosition() const override {
         return 50;
diff --git a/effects/desktopgrid/desktopgrid_config.h b/effects/desktopgrid/desktopgrid_config.h
--- a/effects/desktopgrid/desktopgrid_config.h
+++ b/effects/desktopgrid/desktopgrid_config.h
@@ -42,12 +42,12 @@
     Q_OBJECT
 public:
     explicit DesktopGridEffectConfig(QWidget* parent = 0, const QVariantList& args = QVariantList());
-    ~DesktopGridEffectConfig();
+    ~DesktopGridEffectConfig() override;
 
 public Q_SLOTS:
-    virtual void save();
-    virtual void load();
-    virtual void defaults();
+    void save() override;
+    void load() override;
+    void defaults() override;
 
 private Q_SLOTS:
     void layoutSelectionChanged();
diff --git a/effects/fallapart/fallapart.h b/effects/fallapart/fallapart.h
--- a/effects/fallapart/fallapart.h
+++ b/effects/fallapart/fallapart.h
@@ -33,12 +33,12 @@
     Q_PROPERTY(int blockSize READ configuredBlockSize)
 public:
     FallApartEffect();
-    virtual void reconfigure(ReconfigureFlags);
-    virtual void prePaintScreen(ScreenPrePaintData& data, int time);
-    virtual void prePaintWindow(EffectWindow* w, WindowPrePaintData& data, int time);
-    virtual void paintWindow(EffectWindow* w, int mask, QRegion region, WindowPaintData& data);
-    virtual void postPaintScreen();
-    virtual bool isActive() const;
+    void reconfigure(ReconfigureFlags) override;
+    void prePaintScreen(ScreenPrePaintData& data, int time) override;
+    void prePaintWindow(EffectWindow* w, WindowPrePaintData& data, int time) override;
+    void paintWindow(EffectWindow* w, int mask, QRegion region, WindowPaintData& data) override;
+    void postPaintScreen() override;
+    bool isActive() const override;
 
     int requestedEffectChainPosition() const override {
         return 70;
diff --git a/effects/flipswitch/flipswitch.h b/effects/flipswitch/flipswitch.h
--- a/effects/flipswitch/flipswitch.h
+++ b/effects/flipswitch/flipswitch.h
@@ -43,17 +43,17 @@
     Q_PROPERTY(bool windowTitle READ isWindowTitle)
 public:
     FlipSwitchEffect();
-    ~FlipSwitchEffect();
-
-    virtual void reconfigure(ReconfigureFlags);
-    virtual void prePaintScreen(ScreenPrePaintData& data, int time);
-    virtual void paintScreen(int mask, QRegion region, ScreenPaintData& data);
-    virtual void postPaintScreen();
-    virtual void prePaintWindow(EffectWindow *w, WindowPrePaintData &data, int time);
-    virtual void paintWindow(EffectWindow* w, int mask, QRegion region, WindowPaintData& data);
-    virtual void grabbedKeyboardEvent(QKeyEvent* e);
-    virtual void windowInputMouseEvent(QEvent* e);
-    virtual bool isActive() const;
+    ~FlipSwitchEffect() override;
+
+    void reconfigure(ReconfigureFlags) override;
+    void prePaintScreen(ScreenPrePaintData& data, int time) override;
+    void paintScreen(int mask, QRegion region, ScreenPaintData& data) override;
+    void postPaintScreen() override;
+    void prePaintWindow(EffectWindow *w, WindowPrePaintData &data, int time) override;
+    void paintWindow(EffectWindow* w, int mask, QRegion region, WindowPaintData& data) override;
+    void grabbedKeyboardEvent(QKeyEvent* e) override;
+    void windowInputMouseEvent(QEvent* e) override;
+    bool isActive() const override;
 
     int requestedEffectChainPosition() const override {
         return 50;
diff --git a/effects/flipswitch/flipswitch_config.h b/effects/flipswitch/flipswitch_config.h
--- a/effects/flipswitch/flipswitch_config.h
+++ b/effects/flipswitch/flipswitch_config.h
@@ -42,10 +42,10 @@
     Q_OBJECT
 public:
     explicit FlipSwitchEffectConfig(QWidget* parent = 0, const QVariantList& args = QVariantList());
-    ~FlipSwitchEffectConfig();
+    ~FlipSwitchEffectConfig() override;
 
 public Q_SLOTS:
-    virtual void save();
+    void save() override;
 
 private:
     FlipSwitchEffectConfigForm* m_ui;
diff --git a/effects/highlightwindow/highlightwindow.h b/effects/highlightwindow/highlightwindow.h
--- a/effects/highlightwindow/highlightwindow.h
+++ b/effects/highlightwindow/highlightwindow.h
@@ -32,11 +32,11 @@
     Q_OBJECT
 public:
     HighlightWindowEffect();
-    virtual ~HighlightWindowEffect();
+    ~HighlightWindowEffect() override;
 
-    virtual void prePaintWindow(EffectWindow* w, WindowPrePaintData& data, int time);
-    virtual void paintWindow(EffectWindow* w, int mask, QRegion region, WindowPaintData& data);
-    virtual bool isActive() const;
+    void prePaintWindow(EffectWindow* w, WindowPrePaintData& data, int time) override;
+    void paintWindow(EffectWindow* w, int mask, QRegion region, WindowPaintData& data) override;
+    bool isActive() const override;
 
     int requestedEffectChainPosition() const override {
         return 70;
diff --git a/effects/invert/invert.h b/effects/invert/invert.h
--- a/effects/invert/invert.h
+++ b/effects/invert/invert.h
@@ -38,12 +38,12 @@
     Q_OBJECT
 public:
     InvertEffect();
-    ~InvertEffect();
+    ~InvertEffect() override;
 
-    virtual void drawWindow(EffectWindow* w, int mask, QRegion region, WindowPaintData& data);
-    virtual void paintEffectFrame(KWin::EffectFrame* frame, QRegion region, double opacity, double frameOpacity);
-    virtual bool isActive() const;
-    virtual bool provides(Feature);
+    void drawWindow(EffectWindow* w, int mask, QRegion region, WindowPaintData& data) override;
+    void paintEffectFrame(KWin::EffectFrame* frame, QRegion region, double opacity, double frameOpacity) override;
+    bool isActive() const override;
+    bool provides(Feature) override;
 
     int requestedEffectChainPosition() const override;
 
diff --git a/effects/invert/invert_config.h b/effects/invert/invert_config.h
--- a/effects/invert/invert_config.h
+++ b/effects/invert/invert_config.h
@@ -33,12 +33,12 @@
     Q_OBJECT
 public:
     explicit InvertEffectConfig(QWidget* parent = 0, const QVariantList& args = QVariantList());
-    ~InvertEffectConfig();
+    ~InvertEffectConfig() override;
 
 public Q_SLOTS:
-    virtual void save();
-    virtual void load();
-    virtual void defaults();
+    void save() override;
+    void load() override;
+    void defaults() override;
 
 private:
     KShortcutsEditor* mShortcutEditor;
diff --git a/effects/kscreen/kscreen.h b/effects/kscreen/kscreen.h
--- a/effects/kscreen/kscreen.h
+++ b/effects/kscreen/kscreen.h
@@ -31,15 +31,15 @@
 
 public:
     KscreenEffect();
-    virtual ~KscreenEffect();
+    ~KscreenEffect() override;
 
-    virtual void prePaintScreen(ScreenPrePaintData &data, int time);
-    virtual void postPaintScreen();
-    virtual void prePaintWindow(EffectWindow *w, WindowPrePaintData &data, int time);
-    virtual void paintWindow(EffectWindow *w, int mask, QRegion region, WindowPaintData &data);
+    void prePaintScreen(ScreenPrePaintData &data, int time) override;
+    void postPaintScreen() override;
+    void prePaintWindow(EffectWindow *w, WindowPrePaintData &data, int time) override;
+    void paintWindow(EffectWindow *w, int mask, QRegion region, WindowPaintData &data) override;
 
-    void reconfigure(ReconfigureFlags flags);
-    virtual bool isActive() const;
+    void reconfigure(ReconfigureFlags flags) override;
+    bool isActive() const override;
 
     int requestedEffectChainPosition() const override {
         return 99;
diff --git a/effects/lookingglass/lookingglass.h b/effects/lookingglass/lookingglass.h
--- a/effects/lookingglass/lookingglass.h
+++ b/effects/lookingglass/lookingglass.h
@@ -41,13 +41,13 @@
     Q_PROPERTY(int initialRadius READ initialRadius)
 public:
     LookingGlassEffect();
-    virtual ~LookingGlassEffect();
+    ~LookingGlassEffect() override;
 
-    virtual void reconfigure(ReconfigureFlags);
+    void reconfigure(ReconfigureFlags) override;
 
-    virtual void prePaintScreen(ScreenPrePaintData& data, int time);
+    void prePaintScreen(ScreenPrePaintData& data, int time) override;
     void paintScreen(int mask, QRegion region, ScreenPaintData &data) override;
-    virtual bool isActive() const;
+    bool isActive() const override;
 
     static bool supported();
 
diff --git a/effects/lookingglass/lookingglass_config.h b/effects/lookingglass/lookingglass_config.h
--- a/effects/lookingglass/lookingglass_config.h
+++ b/effects/lookingglass/lookingglass_config.h
@@ -42,10 +42,10 @@
     Q_OBJECT
 public:
     explicit LookingGlassEffectConfig(QWidget* parent = 0, const QVariantList& args = QVariantList());
-    virtual ~LookingGlassEffectConfig();
+    ~LookingGlassEffectConfig() override;
 
-    virtual void save();
-    virtual void defaults();
+    void save() override;
+    void defaults() override;
 
 private:
     LookingGlassEffectConfigForm* m_ui;
diff --git a/effects/magiclamp/magiclamp.h b/effects/magiclamp/magiclamp.h
--- a/effects/magiclamp/magiclamp.h
+++ b/effects/magiclamp/magiclamp.h
@@ -34,12 +34,12 @@
 public:
     MagicLampEffect();
 
-    virtual void reconfigure(ReconfigureFlags);
-    virtual void prePaintScreen(ScreenPrePaintData& data, int time);
-    virtual void prePaintWindow(EffectWindow* w, WindowPrePaintData& data, int time);
-    virtual void paintWindow(EffectWindow* w, int mask, QRegion region, WindowPaintData& data);
-    virtual void postPaintScreen();
-    virtual bool isActive() const;
+    void reconfigure(ReconfigureFlags) override;
+    void prePaintScreen(ScreenPrePaintData& data, int time) override;
+    void prePaintWindow(EffectWindow* w, WindowPrePaintData& data, int time) override;
+    void paintWindow(EffectWindow* w, int mask, QRegion region, WindowPaintData& data) override;
+    void postPaintScreen() override;
+    bool isActive() const override;
 
     int requestedEffectChainPosition() const override {
         return 50;
diff --git a/effects/magiclamp/magiclamp_config.h b/effects/magiclamp/magiclamp_config.h
--- a/effects/magiclamp/magiclamp_config.h
+++ b/effects/magiclamp/magiclamp_config.h
@@ -43,7 +43,7 @@
     explicit MagicLampEffectConfig(QWidget* parent = 0, const QVariantList& args = QVariantList());
 
 public Q_SLOTS:
-    virtual void save();
+    void save() override;
 
 private:
     MagicLampEffectConfigForm* m_ui;
diff --git a/effects/magnifier/magnifier.h b/effects/magnifier/magnifier.h
--- a/effects/magnifier/magnifier.h
+++ b/effects/magnifier/magnifier.h
@@ -39,12 +39,12 @@
     Q_PROPERTY(qreal targetZoom READ targetZoom)
 public:
     MagnifierEffect();
-    virtual ~MagnifierEffect();
-    virtual void reconfigure(ReconfigureFlags);
-    virtual void prePaintScreen(ScreenPrePaintData& data, int time);
-    virtual void paintScreen(int mask, QRegion region, ScreenPaintData& data);
-    virtual void postPaintScreen();
-    virtual bool isActive() const;
+    ~MagnifierEffect() override;
+    void reconfigure(ReconfigureFlags) override;
+    void prePaintScreen(ScreenPrePaintData& data, int time) override;
+    void paintScreen(int mask, QRegion region, ScreenPaintData& data) override;
+    void postPaintScreen() override;
+    bool isActive() const override;
     static bool supported();
 
     // for properties
diff --git a/effects/magnifier/magnifier_config.h b/effects/magnifier/magnifier_config.h
--- a/effects/magnifier/magnifier_config.h
+++ b/effects/magnifier/magnifier_config.h
@@ -42,10 +42,10 @@
     Q_OBJECT
 public:
     explicit MagnifierEffectConfig(QWidget* parent = 0, const QVariantList& args = QVariantList());
-    virtual ~MagnifierEffectConfig();
+    ~MagnifierEffectConfig() override;
 
-    virtual void save();
-    virtual void defaults();
+    void save() override;
+    void defaults() override;
 
 private:
     MagnifierEffectConfigForm* m_ui;
diff --git a/effects/mouseclick/mouseclick.h b/effects/mouseclick/mouseclick.h
--- a/effects/mouseclick/mouseclick.h
+++ b/effects/mouseclick/mouseclick.h
@@ -101,12 +101,12 @@
     Q_PROPERTY(bool enabled READ isEnabled)
 public:
     MouseClickEffect();
-    ~MouseClickEffect();
-    virtual void reconfigure(ReconfigureFlags);
-    virtual void prePaintScreen(ScreenPrePaintData& data, int time);
-    virtual void paintScreen(int mask, QRegion region, ScreenPaintData& data);
-    virtual void postPaintScreen();
-    virtual bool isActive() const;
+    ~MouseClickEffect() override;
+    void reconfigure(ReconfigureFlags) override;
+    void prePaintScreen(ScreenPrePaintData& data, int time) override;
+    void paintScreen(int mask, QRegion region, ScreenPaintData& data) override;
+    void postPaintScreen() override;
+    bool isActive() const override;
 
     // for properties
     QColor color1() const {
diff --git a/effects/mouseclick/mouseclick_config.h b/effects/mouseclick/mouseclick_config.h
--- a/effects/mouseclick/mouseclick_config.h
+++ b/effects/mouseclick/mouseclick_config.h
@@ -42,9 +42,9 @@
     Q_OBJECT
 public:
     explicit MouseClickEffectConfig(QWidget* parent = 0, const QVariantList& args = QVariantList());
-    virtual ~MouseClickEffectConfig();
+    ~MouseClickEffectConfig() override;
 
-    virtual void save();
+    void save() override;
 
 private:
     MouseClickEffectConfigForm* m_ui;
diff --git a/effects/mousemark/mousemark.h b/effects/mousemark/mousemark.h
--- a/effects/mousemark/mousemark.h
+++ b/effects/mousemark/mousemark.h
@@ -38,10 +38,10 @@
     Q_PROPERTY(QColor color READ configuredColor)
 public:
     MouseMarkEffect();
-    ~MouseMarkEffect();
-    virtual void reconfigure(ReconfigureFlags);
-    virtual void paintScreen(int mask, QRegion region, ScreenPaintData& data);
-    virtual bool isActive() const;
+    ~MouseMarkEffect() override;
+    void reconfigure(ReconfigureFlags) override;
+    void paintScreen(int mask, QRegion region, ScreenPaintData& data) override;
+    bool isActive() const override;
 
     // for properties
     int configuredWidth() const {
diff --git a/effects/mousemark/mousemark_config.h b/effects/mousemark/mousemark_config.h
--- a/effects/mousemark/mousemark_config.h
+++ b/effects/mousemark/mousemark_config.h
@@ -42,9 +42,9 @@
     Q_OBJECT
 public:
     explicit MouseMarkEffectConfig(QWidget* parent = 0, const QVariantList& args = QVariantList());
-    virtual ~MouseMarkEffectConfig();
+    ~MouseMarkEffectConfig() override;
 
-    virtual void save();
+    void save() override;
 
 private:
     MouseMarkEffectConfigForm* m_ui;
diff --git a/effects/presentwindows/presentwindows.h b/effects/presentwindows/presentwindows.h
--- a/effects/presentwindows/presentwindows.h
+++ b/effects/presentwindows/presentwindows.h
@@ -107,25 +107,25 @@
 
 public:
     PresentWindowsEffect();
-    virtual ~PresentWindowsEffect();
+    ~PresentWindowsEffect() override;
 
-    virtual void reconfigure(ReconfigureFlags);
-    virtual void* proxy();
+    void reconfigure(ReconfigureFlags) override;
+    void* proxy() override;
 
     // Screen painting
-    virtual void prePaintScreen(ScreenPrePaintData &data, int time);
-    virtual void paintScreen(int mask, QRegion region, ScreenPaintData &data);
-    virtual void postPaintScreen();
+    void prePaintScreen(ScreenPrePaintData &data, int time) override;
+    void paintScreen(int mask, QRegion region, ScreenPaintData &data) override;
+    void postPaintScreen() override;
 
     // Window painting
-    virtual void prePaintWindow(EffectWindow *w, WindowPrePaintData &data, int time);
-    virtual void paintWindow(EffectWindow *w, int mask, QRegion region, WindowPaintData &data);
+    void prePaintWindow(EffectWindow *w, WindowPrePaintData &data, int time) override;
+    void paintWindow(EffectWindow *w, int mask, QRegion region, WindowPaintData &data) override;
 
     // User interaction
-    virtual bool borderActivated(ElectricBorder border);
-    virtual void windowInputMouseEvent(QEvent *e);
-    virtual void grabbedKeyboardEvent(QKeyEvent *e);
-    virtual bool isActive() const;
+    bool borderActivated(ElectricBorder border) override;
+    void windowInputMouseEvent(QEvent *e) override;
+    void grabbedKeyboardEvent(QKeyEvent *e) override;
+    bool isActive() const override;
 
     bool touchDown(quint32 id, const QPointF &pos, quint32 time) override;
     bool touchMotion(quint32 id, const QPointF &pos, quint32 time) override;
diff --git a/effects/presentwindows/presentwindows_config.h b/effects/presentwindows/presentwindows_config.h
--- a/effects/presentwindows/presentwindows_config.h
+++ b/effects/presentwindows/presentwindows_config.h
@@ -41,11 +41,11 @@
     Q_OBJECT
 public:
     explicit PresentWindowsEffectConfig(QWidget* parent = 0, const QVariantList& args = QVariantList());
-    ~PresentWindowsEffectConfig();
+    ~PresentWindowsEffectConfig() override;
 
 public Q_SLOTS:
-    virtual void save();
-    virtual void defaults();
+    void save() override;
+    void defaults() override;
 
 private:
     PresentWindowsEffectConfigForm* m_ui;
diff --git a/effects/resize/resize.h b/effects/resize/resize.h
--- a/effects/resize/resize.h
+++ b/effects/resize/resize.h
@@ -34,15 +34,15 @@
     Q_PROPERTY(bool outline READ isOutline)
 public:
     ResizeEffect();
-    ~ResizeEffect();
-    virtual inline bool provides(Effect::Feature ef) {
+    ~ResizeEffect() override;
+    inline bool provides(Effect::Feature ef) override {
         return ef == Effect::Resize;
     }
-    inline bool isActive() const { return m_active || AnimationEffect::isActive(); }
-    virtual void prePaintScreen(ScreenPrePaintData& data, int time);
-    virtual void prePaintWindow(EffectWindow* w, WindowPrePaintData& data, int time);
-    virtual void paintWindow(EffectWindow* w, int mask, QRegion region, WindowPaintData& data);
-    virtual void reconfigure(ReconfigureFlags);
+    inline bool isActive() const override { return m_active || AnimationEffect::isActive(); }
+    void prePaintScreen(ScreenPrePaintData& data, int time) override;
+    void prePaintWindow(EffectWindow* w, WindowPrePaintData& data, int time) override;
+    void paintWindow(EffectWindow* w, int mask, QRegion region, WindowPaintData& data) override;
+    void reconfigure(ReconfigureFlags) override;
 
     int requestedEffectChainPosition() const override {
         return 60;
diff --git a/effects/resize/resize_config.h b/effects/resize/resize_config.h
--- a/effects/resize/resize_config.h
+++ b/effects/resize/resize_config.h
@@ -43,7 +43,7 @@
     explicit ResizeEffectConfig(QWidget* parent = 0, const QVariantList& args = QVariantList());
 
 public Q_SLOTS:
-    virtual void save();
+    void save() override;
 
 private:
     ResizeEffectConfigForm* m_ui;
diff --git a/effects/screenedge/screenedgeeffect.h b/effects/screenedge/screenedgeeffect.h
--- a/effects/screenedge/screenedgeeffect.h
+++ b/effects/screenedge/screenedgeeffect.h
@@ -35,10 +35,10 @@
     Q_OBJECT
 public:
     ScreenEdgeEffect();
-    virtual ~ScreenEdgeEffect();
-    virtual void prePaintScreen(ScreenPrePaintData &data, int time);
-    virtual void paintScreen(int mask, QRegion region, ScreenPaintData &data);
-    virtual bool isActive() const;
+    ~ScreenEdgeEffect() override;
+    void prePaintScreen(ScreenPrePaintData &data, int time) override;
+    void paintScreen(int mask, QRegion region, ScreenPaintData &data) override;
+    bool isActive() const override;
 
     int requestedEffectChainPosition() const override {
         return 90;
diff --git a/effects/showfps/showfps.h b/effects/showfps/showfps.h
--- a/effects/showfps/showfps.h
+++ b/effects/showfps/showfps.h
@@ -44,11 +44,11 @@
     Q_PROPERTY(QColor textColor READ configuredTextColor)
 public:
     ShowFpsEffect();
-    virtual void reconfigure(ReconfigureFlags);
-    virtual void prePaintScreen(ScreenPrePaintData& data, int time);
-    virtual void paintScreen(int mask, QRegion region, ScreenPaintData& data);
-    virtual void paintWindow(EffectWindow* w, int mask, QRegion region, WindowPaintData& data);
-    virtual void postPaintScreen();
+    void reconfigure(ReconfigureFlags) override;
+    void prePaintScreen(ScreenPrePaintData& data, int time) override;
+    void paintScreen(int mask, QRegion region, ScreenPaintData& data) override;
+    void paintWindow(EffectWindow* w, int mask, QRegion region, WindowPaintData& data) override;
+    void postPaintScreen() override;
     enum { INSIDE_GRAPH, NOWHERE, TOP_LEFT, TOP_RIGHT, BOTTOM_LEFT, BOTTOM_RIGHT }; // fps text position
 
     // for properties
diff --git a/effects/showfps/showfps_config.h b/effects/showfps/showfps_config.h
--- a/effects/showfps/showfps_config.h
+++ b/effects/showfps/showfps_config.h
@@ -33,10 +33,10 @@
     Q_OBJECT
 public:
     explicit ShowFpsEffectConfig(QWidget* parent = 0, const QVariantList& args = QVariantList());
-    ~ShowFpsEffectConfig();
+    ~ShowFpsEffectConfig() override;
 
 public Q_SLOTS:
-    virtual void save();
+    void save() override;
 
 private:
     Ui::ShowFpsEffectConfigForm *m_ui;
diff --git a/effects/slide/slide_config.h b/effects/slide/slide_config.h
--- a/effects/slide/slide_config.h
+++ b/effects/slide/slide_config.h
@@ -34,9 +34,9 @@
 
 public:
     explicit SlideEffectConfig(QWidget *parent = nullptr, const QVariantList &args = QVariantList());
-    ~SlideEffectConfig();
+    ~SlideEffectConfig() override;
 
-    void save();
+    void save() override;
 
 private:
     ::Ui::SlideEffectConfig m_ui;
diff --git a/effects/slideback/slideback.h b/effects/slideback/slideback.h
--- a/effects/slideback/slideback.h
+++ b/effects/slideback/slideback.h
@@ -34,13 +34,13 @@
 public:
     SlideBackEffect();
 
-    virtual void prePaintWindow(EffectWindow *w, WindowPrePaintData &data, int time);
-    virtual void paintWindow(EffectWindow* w, int mask, QRegion region, WindowPaintData& data);
-    virtual void postPaintWindow(EffectWindow* w);
+    void prePaintWindow(EffectWindow *w, WindowPrePaintData &data, int time) override;
+    void paintWindow(EffectWindow* w, int mask, QRegion region, WindowPaintData& data) override;
+    void postPaintWindow(EffectWindow* w) override;
 
-    virtual void prePaintScreen(ScreenPrePaintData &data, int time);
-    virtual void postPaintScreen();
-    virtual bool isActive() const;
+    void prePaintScreen(ScreenPrePaintData &data, int time) override;
+    void postPaintScreen() override;
+    bool isActive() const override;
 
     int requestedEffectChainPosition() const override {
         return 50;
diff --git a/effects/startupfeedback/startupfeedback.h b/effects/startupfeedback/startupfeedback.h
--- a/effects/startupfeedback/startupfeedback.h
+++ b/effects/startupfeedback/startupfeedback.h
@@ -36,13 +36,13 @@
     Q_PROPERTY(int type READ type)
 public:
     StartupFeedbackEffect();
-    virtual ~StartupFeedbackEffect();
+    ~StartupFeedbackEffect() override;
 
-    virtual void reconfigure(ReconfigureFlags flags);
-    virtual void prePaintScreen(ScreenPrePaintData& data, int time);
-    virtual void paintScreen(int mask, QRegion region, ScreenPaintData& data);
-    virtual void postPaintScreen();
-    virtual bool isActive() const;
+    void reconfigure(ReconfigureFlags flags) override;
+    void prePaintScreen(ScreenPrePaintData& data, int time) override;
+    void paintScreen(int mask, QRegion region, ScreenPaintData& data) override;
+    void postPaintScreen() override;
+    bool isActive() const override;
 
     int requestedEffectChainPosition() const override {
         return 90;
diff --git a/effects/thumbnailaside/thumbnailaside.h b/effects/thumbnailaside/thumbnailaside.h
--- a/effects/thumbnailaside/thumbnailaside.h
+++ b/effects/thumbnailaside/thumbnailaside.h
@@ -45,9 +45,9 @@
     Q_PROPERTY(int screen READ configuredScreen)
 public:
     ThumbnailAsideEffect();
-    virtual void reconfigure(ReconfigureFlags);
-    virtual void paintScreen(int mask, QRegion region, ScreenPaintData& data);
-    virtual void paintWindow(EffectWindow *w, int mask, QRegion region, WindowPaintData &data);
+    void reconfigure(ReconfigureFlags) override;
+    void paintScreen(int mask, QRegion region, ScreenPaintData& data) override;
+    void paintWindow(EffectWindow *w, int mask, QRegion region, WindowPaintData &data) override;
 
     // for properties
     int configuredMaxWidth() const {
@@ -67,7 +67,7 @@
     void slotWindowClosed(KWin::EffectWindow *w);
     void slotWindowGeometryShapeChanged(KWin::EffectWindow *w, const QRect &old);
     void slotWindowDamaged(KWin::EffectWindow* w, const QRect& damage);
-    virtual bool isActive() const;
+    bool isActive() const override;
     void repaintAll();
 private:
     void addThumbnail(EffectWindow* w);
diff --git a/effects/thumbnailaside/thumbnailaside_config.h b/effects/thumbnailaside/thumbnailaside_config.h
--- a/effects/thumbnailaside/thumbnailaside_config.h
+++ b/effects/thumbnailaside/thumbnailaside_config.h
@@ -42,9 +42,9 @@
     Q_OBJECT
 public:
     explicit ThumbnailAsideEffectConfig(QWidget* parent = 0, const QVariantList& args = QVariantList());
-    virtual ~ThumbnailAsideEffectConfig();
+    ~ThumbnailAsideEffectConfig() override;
 
-    virtual void save();
+    void save() override;
 
 private:
     ThumbnailAsideEffectConfigForm* m_ui;
diff --git a/effects/touchpoints/touchpoints.h b/effects/touchpoints/touchpoints.h
--- a/effects/touchpoints/touchpoints.h
+++ b/effects/touchpoints/touchpoints.h
@@ -37,7 +37,7 @@
     Q_PROPERTY(int ringCount READ ringCount)
 public:
     TouchPointsEffect();
-    ~TouchPointsEffect();
+    ~TouchPointsEffect() override;
     void prePaintScreen(ScreenPrePaintData& data, int time) override;
     void paintScreen(int mask, QRegion region, ScreenPaintData& data) override;
     void postPaintScreen() override;
diff --git a/effects/trackmouse/trackmouse.h b/effects/trackmouse/trackmouse.h
--- a/effects/trackmouse/trackmouse.h
+++ b/effects/trackmouse/trackmouse.h
@@ -39,12 +39,12 @@
     Q_PROPERTY(bool mousePolling READ isMousePolling)
 public:
     TrackMouseEffect();
-    virtual ~TrackMouseEffect();
-    virtual void prePaintScreen(ScreenPrePaintData& data, int time);
-    virtual void paintScreen(int mask, QRegion region, ScreenPaintData& data);
-    virtual void postPaintScreen();
-    virtual void reconfigure(ReconfigureFlags);
-    virtual bool isActive() const;
+    ~TrackMouseEffect() override;
+    void prePaintScreen(ScreenPrePaintData& data, int time) override;
+    void paintScreen(int mask, QRegion region, ScreenPaintData& data) override;
+    void postPaintScreen() override;
+    void reconfigure(ReconfigureFlags) override;
+    bool isActive() const override;
 
     // for properties
     Qt::KeyboardModifiers modifiers() const {
diff --git a/effects/trackmouse/trackmouse_config.h b/effects/trackmouse/trackmouse_config.h
--- a/effects/trackmouse/trackmouse_config.h
+++ b/effects/trackmouse/trackmouse_config.h
@@ -43,12 +43,12 @@
     Q_OBJECT
 public:
     explicit TrackMouseEffectConfig(QWidget* parent = 0, const QVariantList& args = QVariantList());
-    ~TrackMouseEffectConfig();
+    ~TrackMouseEffectConfig() override;
 
 public Q_SLOTS:
-    virtual void save();
-    virtual void load();
-    virtual void defaults();
+    void save() override;
+    void load() override;
+    void defaults() override;
 private Q_SLOTS:
     void shortcutChanged(const QKeySequence &seq);
 private:
diff --git a/effects/windowgeometry/windowgeometry.h b/effects/windowgeometry/windowgeometry.h
--- a/effects/windowgeometry/windowgeometry.h
+++ b/effects/windowgeometry/windowgeometry.h
@@ -33,14 +33,14 @@
     Q_PROPERTY(bool handlesResizes READ isHandlesResizes)
 public:
     WindowGeometry();
-    ~WindowGeometry();
+    ~WindowGeometry() override;
 
-    inline bool provides(Effect::Feature ef) {
+    inline bool provides(Effect::Feature ef) override {
         return ef == Effect::GeometryTip;
     }
-    void reconfigure(ReconfigureFlags);
-    void paintScreen(int mask, QRegion region, ScreenPaintData &data);
-    virtual bool isActive() const;
+    void reconfigure(ReconfigureFlags) override;
+    void paintScreen(int mask, QRegion region, ScreenPaintData &data) override;
+    bool isActive() const override;
 
     int requestedEffectChainPosition() const override {
         return 90;
diff --git a/effects/windowgeometry/windowgeometry_config.h b/effects/windowgeometry/windowgeometry_config.h
--- a/effects/windowgeometry/windowgeometry_config.h
+++ b/effects/windowgeometry/windowgeometry_config.h
@@ -41,11 +41,11 @@
     Q_OBJECT
 public:
     explicit WindowGeometryConfig(QWidget* parent = 0, const QVariantList& args = QVariantList());
-    ~WindowGeometryConfig();
+    ~WindowGeometryConfig() override;
 
 public Q_SLOTS:
-    void save();
-    void defaults();
+    void save() override;
+    void defaults() override;
 
 private:
     WindowGeometryConfigForm* myUi;
diff --git a/effects/wobblywindows/wobblywindows.h b/effects/wobblywindows/wobblywindows.h
--- a/effects/wobblywindows/wobblywindows.h
+++ b/effects/wobblywindows/wobblywindows.h
@@ -44,14 +44,14 @@
 public:
 
     WobblyWindowsEffect();
-    virtual ~WobblyWindowsEffect();
-
-    virtual void reconfigure(ReconfigureFlags);
-    virtual void prePaintScreen(ScreenPrePaintData& data, int time);
-    virtual void prePaintWindow(EffectWindow* w, WindowPrePaintData& data, int time);
-    virtual void paintWindow(EffectWindow* w, int mask, QRegion region, WindowPaintData& data);
-    virtual void postPaintScreen();
-    virtual bool isActive() const;
+    ~WobblyWindowsEffect() override;
+
+    void reconfigure(ReconfigureFlags) override;
+    void prePaintScreen(ScreenPrePaintData& data, int time) override;
+    void prePaintWindow(EffectWindow* w, WindowPrePaintData& data, int time) override;
+    void paintWindow(EffectWindow* w, int mask, QRegion region, WindowPaintData& data) override;
+    void postPaintScreen() override;
+    bool isActive() const override;
 
     int requestedEffectChainPosition() const override {
         // Please notice that the Wobbly Windows effect has to be placed
diff --git a/effects/wobblywindows/wobblywindows_config.h b/effects/wobblywindows/wobblywindows_config.h
--- a/effects/wobblywindows/wobblywindows_config.h
+++ b/effects/wobblywindows/wobblywindows_config.h
@@ -35,10 +35,10 @@
     Q_OBJECT
 public:
     explicit WobblyWindowsEffectConfig(QWidget* parent = 0, const QVariantList& args = QVariantList());
-    ~WobblyWindowsEffectConfig();
+    ~WobblyWindowsEffectConfig() override;
 
 public Q_SLOTS:
-    virtual void save();
+    void save() override;
 
 private Q_SLOTS:
     void wobblinessChanged();
diff --git a/effects/zoom/zoom.h b/effects/zoom/zoom.h
--- a/effects/zoom/zoom.h
+++ b/effects/zoom/zoom.h
@@ -46,12 +46,12 @@
     Q_PROPERTY(qreal targetZoom READ targetZoom)
 public:
     ZoomEffect();
-    virtual ~ZoomEffect();
-    virtual void reconfigure(ReconfigureFlags flags);
-    virtual void prePaintScreen(ScreenPrePaintData& data, int time);
-    virtual void paintScreen(int mask, QRegion region, ScreenPaintData& data);
-    virtual void postPaintScreen();
-    virtual bool isActive() const;
+    ~ZoomEffect() override;
+    void reconfigure(ReconfigureFlags flags) override;
+    void prePaintScreen(ScreenPrePaintData& data, int time) override;
+    void paintScreen(int mask, QRegion region, ScreenPaintData& data) override;
+    void postPaintScreen() override;
+    bool isActive() const override;
     // for properties
     qreal configuredZoomFactor() const {
         return zoomFactor;
diff --git a/effects/zoom/zoom_config.h b/effects/zoom/zoom_config.h
--- a/effects/zoom/zoom_config.h
+++ b/effects/zoom/zoom_config.h
@@ -42,10 +42,10 @@
     Q_OBJECT
 public:
     explicit ZoomEffectConfig(QWidget* parent = 0, const QVariantList& args = QVariantList());
-    virtual ~ZoomEffectConfig();
+    ~ZoomEffectConfig() override;
 
 public Q_SLOTS:
-    virtual void save();
+    void save() override;
 
 private:
     ZoomEffectConfigForm* m_ui;
diff --git a/focuschain.h b/focuschain.h
--- a/focuschain.h
+++ b/focuschain.h
@@ -55,7 +55,7 @@
         Update,
         MakeFirstMinimized = MakeFirst
     };
-    virtual ~FocusChain();
+    ~FocusChain() override;
     /**
      * @brief Updates the position of the @p client according to the requested @p change in the
      * focus chain.
diff --git a/geometrytip.h b/geometrytip.h
--- a/geometrytip.h
+++ b/geometrytip.h
@@ -32,7 +32,7 @@
     Q_OBJECT
 public:
     GeometryTip(const Xcb::GeometryHints* xSizeHints);
-    ~GeometryTip();
+    ~GeometryTip() override;
     void setGeometry(const QRect& geom);
 
 private:
diff --git a/globalshortcuts.h b/globalshortcuts.h
--- a/globalshortcuts.h
+++ b/globalshortcuts.h
@@ -49,7 +49,7 @@
     Q_OBJECT
 public:
     explicit GlobalShortcutsManager(QObject *parent = nullptr);
-    virtual ~GlobalShortcutsManager();
+    ~GlobalShortcutsManager() override;
     void init();
 
     /**
@@ -149,7 +149,7 @@
     InternalGlobalShortcut(Qt::KeyboardModifiers pointerButtonModifiers, Qt::MouseButtons pointerButtons, QAction *action);
     InternalGlobalShortcut(Qt::KeyboardModifiers axisModifiers, PointerAxisDirection axis, QAction *action);
     InternalGlobalShortcut(Qt::KeyboardModifiers swipeModifier, SwipeDirection direction, QAction *action);
-    virtual ~InternalGlobalShortcut();
+    ~InternalGlobalShortcut() override;
 
     void invoke() override;
 
diff --git a/idle_inhibition.h b/idle_inhibition.h
--- a/idle_inhibition.h
+++ b/idle_inhibition.h
@@ -44,7 +44,7 @@
     Q_OBJECT
 public:
     explicit IdleInhibition(IdleInterface *idle);
-    ~IdleInhibition();
+    ~IdleInhibition() override;
 
     void registerShellClient(ShellClient *client);
 
diff --git a/input.h b/input.h
--- a/input.h
+++ b/input.h
@@ -92,7 +92,7 @@
         KeyboardKeyPressed,
         KeyboardKeyAutoRepeat
     };
-    virtual ~InputRedirection();
+    ~InputRedirection() override;
     void init();
 
     /**
@@ -378,7 +378,7 @@
 {
     Q_OBJECT
 public:
-    virtual ~InputDeviceHandler();
+    ~InputDeviceHandler() override;
     virtual void init();
 
     void update();
diff --git a/kcmkwin/kwincompositing/compositing.h b/kcmkwin/kwincompositing/compositing.h
--- a/kcmkwin/kwincompositing/compositing.h
+++ b/kcmkwin/kwincompositing/compositing.h
@@ -140,7 +140,7 @@
     int columnCount(const QModelIndex &parent = QModelIndex()) const override;
     QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const override;
 
-    virtual QHash< int, QByteArray > roleNames() const override;
+    QHash< int, QByteArray > roleNames() const override;
 
     Q_INVOKABLE int compositingTypeForIndex(int row) const;
     Q_INVOKABLE int indexForCompositingType(int type) const;
@@ -161,7 +161,7 @@
     Q_OBJECT
 public:
     explicit OpenGLPlatformInterfaceModel(QObject *parent = nullptr);
-    virtual ~OpenGLPlatformInterfaceModel();
+    ~OpenGLPlatformInterfaceModel() override;
     QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const override;
     int rowCount(const QModelIndex &parent = QModelIndex()) const override;
 
diff --git a/kcmkwin/kwindecoration/declarative-plugin/buttonsmodel.h b/kcmkwin/kwindecoration/declarative-plugin/buttonsmodel.h
--- a/kcmkwin/kwindecoration/declarative-plugin/buttonsmodel.h
+++ b/kcmkwin/kwindecoration/declarative-plugin/buttonsmodel.h
@@ -36,7 +36,7 @@
 public:
     explicit ButtonsModel(const QVector< DecorationButtonType > &buttons, QObject *parent = 0);
     explicit ButtonsModel(QObject *parent = nullptr);
-    virtual ~ButtonsModel();
+    ~ButtonsModel() override;
     QVariant data(const QModelIndex& index, int role = Qt::DisplayRole) const override;
     int rowCount(const QModelIndex& parent = QModelIndex()) const override;
     QHash< int, QByteArray > roleNames() const override;
diff --git a/kcmkwin/kwindecoration/declarative-plugin/previewbridge.h b/kcmkwin/kwindecoration/declarative-plugin/previewbridge.h
--- a/kcmkwin/kwindecoration/declarative-plugin/previewbridge.h
+++ b/kcmkwin/kwindecoration/declarative-plugin/previewbridge.h
@@ -45,7 +45,7 @@
     Q_PROPERTY(bool valid READ isValid NOTIFY validChanged)
 public:
     explicit PreviewBridge(QObject *parent = nullptr);
-    virtual ~PreviewBridge();
+    ~PreviewBridge() override;
     std::unique_ptr<DecoratedClientPrivate> createClient(DecoratedClient *client, Decoration *decoration) override;
     void update(Decoration* decoration, const QRect& geometry) override;
     std::unique_ptr<DecorationSettingsPrivate> settings(DecorationSettings *parent) override;
@@ -99,7 +99,7 @@
 
 public:
     explicit BridgeItem(QObject *parent = nullptr);
-    virtual ~BridgeItem();
+    ~BridgeItem() override;
 
     void setPlugin(const QString &plugin) {
         m_bridge->setPlugin(plugin);
diff --git a/kcmkwin/kwindecoration/declarative-plugin/previewbutton.h b/kcmkwin/kwindecoration/declarative-plugin/previewbutton.h
--- a/kcmkwin/kwindecoration/declarative-plugin/previewbutton.h
+++ b/kcmkwin/kwindecoration/declarative-plugin/previewbutton.h
@@ -44,7 +44,7 @@
 
 public:
     explicit PreviewButtonItem(QQuickItem *parent = nullptr);
-    virtual ~PreviewButtonItem();
+    ~PreviewButtonItem() override;
     void paint(QPainter *painter) override;
 
     PreviewBridge *bridge() const;
diff --git a/kcmkwin/kwindecoration/declarative-plugin/previewclient.h b/kcmkwin/kwindecoration/declarative-plugin/previewclient.h
--- a/kcmkwin/kwindecoration/declarative-plugin/previewclient.h
+++ b/kcmkwin/kwindecoration/declarative-plugin/previewclient.h
@@ -64,7 +64,7 @@
     Q_PROPERTY(bool bordersBottomEdge READ bordersBottomEdge WRITE setBordersBottomEdge NOTIFY bordersBottomEdgeChanged)
 public:
     explicit PreviewClient(DecoratedClient *client, Decoration *decoration);
-    virtual ~PreviewClient();
+    ~PreviewClient() override;
 
     QString caption() const override;
     WId decorationId() const override;
@@ -110,7 +110,7 @@
     void requestShowApplicationMenu(const QRect &rect, int actionId) override;
     void requestToggleOnAllDesktops() override;
 
-    void showApplicationMenu(int actionId);
+    void showApplicationMenu(int actionId) override;
 
     void setCaption(const QString &caption);
     void setActive(bool active);
diff --git a/kcmkwin/kwindecoration/declarative-plugin/previewitem.h b/kcmkwin/kwindecoration/declarative-plugin/previewitem.h
--- a/kcmkwin/kwindecoration/declarative-plugin/previewitem.h
+++ b/kcmkwin/kwindecoration/declarative-plugin/previewitem.h
@@ -47,8 +47,8 @@
     Q_PROPERTY(bool drawBackground READ isDrawingBackground WRITE setDrawingBackground NOTIFY drawingBackgroundChanged)
 public:
     PreviewItem(QQuickItem *parent = nullptr);
-    virtual ~PreviewItem();
-    void paint(QPainter *painter);
+    ~PreviewItem() override;
+    void paint(QPainter *painter) override;
 
     KDecoration2::Decoration *decoration() const;
     void setDecoration(KDecoration2::Decoration *deco);
diff --git a/kcmkwin/kwindecoration/declarative-plugin/previewsettings.h b/kcmkwin/kwindecoration/declarative-plugin/previewsettings.h
--- a/kcmkwin/kwindecoration/declarative-plugin/previewsettings.h
+++ b/kcmkwin/kwindecoration/declarative-plugin/previewsettings.h
@@ -38,7 +38,7 @@
     Q_OBJECT
 public:
     explicit BorderSizesModel(QObject *parent = 0);
-    virtual ~BorderSizesModel();
+    ~BorderSizesModel() override;
     QVariant data(const QModelIndex& index, int role = Qt::DisplayRole) const override;
     int rowCount(const QModelIndex& parent = QModelIndex()) const override;
     QHash< int, QByteArray > roleNames() const override;
@@ -70,7 +70,7 @@
     Q_PROPERTY(QFont font READ font WRITE setFont NOTIFY fontChanged)
 public:
     explicit PreviewSettings(DecorationSettings *parent);
-    virtual ~PreviewSettings();
+    ~PreviewSettings() override;
     bool isAlphaChannelSupported() const override;
     bool isOnAllDesktopsAvailable() const override;
     bool isCloseOnDoubleClickOnMenu() const override {
@@ -100,7 +100,7 @@
     }
     void setBorderSizesIndex(int index);
 
-    QFont font() const {
+    QFont font() const override {
         return m_font;
     }
     void setFont(const QFont &font);
@@ -132,7 +132,7 @@
     Q_PROPERTY(int borderSizesIndex READ borderSizesIndex WRITE setBorderSizesIndex NOTIFY borderSizesIndexChanged)
 public:
     explicit Settings(QObject *parent = nullptr);
-    virtual ~Settings();
+    ~Settings() override;
 
     PreviewBridge *bridge() const;
     void setBridge(PreviewBridge *bridge);
diff --git a/kcmkwin/kwindecoration/decorationmodel.h b/kcmkwin/kwindecoration/decorationmodel.h
--- a/kcmkwin/kwindecoration/decorationmodel.h
+++ b/kcmkwin/kwindecoration/decorationmodel.h
@@ -43,7 +43,7 @@
 
 public:
     explicit DecorationsModel(QObject *parent = nullptr);
-    virtual ~DecorationsModel();
+    ~DecorationsModel() override;
 
     QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const override;
     int rowCount(const QModelIndex &parent = QModelIndex()) const override;
diff --git a/kcmkwin/kwinoptions/main.h b/kcmkwin/kwinoptions/main.h
--- a/kcmkwin/kwinoptions/main.h
+++ b/kcmkwin/kwinoptions/main.h
@@ -42,12 +42,12 @@
 public:
 
     KWinOptions(QWidget *parent, const QVariantList &args);
-    virtual ~KWinOptions();
+    ~KWinOptions() override;
 
-    void load();
-    void save();
-    void defaults();
-    QString quickHelp() const;
+    void load() override;
+    void save() override;
+    void defaults() override;
+    QString quickHelp() const override;
 
 
 protected Q_SLOTS:
@@ -75,11 +75,11 @@
 public:
 
     KActionsOptions(QWidget *parent, const QVariantList &args);
-    virtual ~KActionsOptions();
+    ~KActionsOptions() override;
 
-    void load();
-    void save();
-    void defaults();
+    void load() override;
+    void save() override;
+    void defaults() override;
 
 protected Q_SLOTS:
 
diff --git a/kcmkwin/kwinoptions/mouse.h b/kcmkwin/kwinoptions/mouse.h
--- a/kcmkwin/kwinoptions/mouse.h
+++ b/kcmkwin/kwinoptions/mouse.h
@@ -54,15 +54,15 @@
 public:
 
     KTitleBarActionsConfig(bool _standAlone, KConfig *_config, QWidget *parent);
-    ~KTitleBarActionsConfig();
+    ~KTitleBarActionsConfig() override;
 
-    void load();
-    void save();
-    void defaults();
+    void load() override;
+    void save() override;
+    void defaults() override;
 
 protected:
-    void showEvent(QShowEvent *ev);
-    void changeEvent(QEvent *ev);
+    void showEvent(QShowEvent *ev) override;
+    void changeEvent(QEvent *ev) override;
 
 public Q_SLOTS:
     void changed() {
@@ -98,14 +98,14 @@
 public:
 
     KWindowActionsConfig(bool _standAlone, KConfig *_config, QWidget *parent);
-    ~KWindowActionsConfig();
+    ~KWindowActionsConfig() override;
 
-    void load();
-    void save();
-    void defaults();
+    void load() override;
+    void save() override;
+    void defaults() override;
 
 protected:
-    void showEvent(QShowEvent *ev);
+    void showEvent(QShowEvent *ev) override;
 
 public Q_SLOTS:
     void changed() {
diff --git a/kcmkwin/kwinoptions/windows.h b/kcmkwin/kwinoptions/windows.h
--- a/kcmkwin/kwinoptions/windows.h
+++ b/kcmkwin/kwinoptions/windows.h
@@ -71,14 +71,14 @@
     Q_OBJECT
 public:
     KFocusConfig(bool _standAlone, KConfig *_config, QWidget *parent);
-    ~KFocusConfig();
+    ~KFocusConfig() override;
 
-    void load();
-    void save();
-    void defaults();
+    void load() override;
+    void save() override;
+    void defaults() override;
 
 protected:
-    void showEvent(QShowEvent *ev);
+    void showEvent(QShowEvent *ev) override;
 
 private Q_SLOTS:
     void setDelayFocusEnabled();
@@ -119,14 +119,14 @@
     Q_OBJECT
 public:
     KMovingConfig(bool _standAlone, KConfig *config, QWidget *parent);
-    ~KMovingConfig();
+    ~KMovingConfig() override;
 
-    void load();
-    void save();
-    void defaults();
+    void load() override;
+    void save() override;
+    void defaults() override;
 
 protected:
-    void showEvent(QShowEvent *ev);
+    void showEvent(QShowEvent *ev) override;
 
 private Q_SLOTS:
     void changed() {
@@ -156,14 +156,14 @@
     Q_OBJECT
 public:
     KAdvancedConfig(bool _standAlone, KConfig *config, QWidget *parent);
-    ~KAdvancedConfig();
+    ~KAdvancedConfig() override;
 
-    void load();
-    void save();
-    void defaults();
+    void load() override;
+    void save() override;
+    void defaults() override;
 
 protected:
-    void showEvent(QShowEvent *ev);
+    void showEvent(QShowEvent *ev) override;
 
 private Q_SLOTS:
     void shadeHoverChanged(bool);
diff --git a/kcmkwin/kwinrules/kcm.h b/kcmkwin/kwinrules/kcm.h
--- a/kcmkwin/kwinrules/kcm.h
+++ b/kcmkwin/kwinrules/kcm.h
@@ -36,10 +36,10 @@
     Q_OBJECT
 public:
     KCMRules(QWidget *parent, const QVariantList &args);
-    virtual void load();
-    virtual void save();
-    virtual void defaults();
-    virtual QString quickHelp() const;
+    void load() override;
+    void save() override;
+    void defaults() override;
+    QString quickHelp() const override;
 protected Q_SLOTS:
     void moduleChanged(bool state);
 private:
diff --git a/kcmkwin/kwinrules/ruleslist.h b/kcmkwin/kwinrules/ruleslist.h
--- a/kcmkwin/kwinrules/ruleslist.h
+++ b/kcmkwin/kwinrules/ruleslist.h
@@ -33,7 +33,7 @@
     Q_OBJECT
 public:
     explicit KCMRulesList(QWidget* parent = nullptr);
-    virtual ~KCMRulesList();
+    ~KCMRulesList() override;
     void load();
     void save();
     void defaults();
diff --git a/kcmkwin/kwinrules/ruleswidget.h b/kcmkwin/kwinrules/ruleswidget.h
--- a/kcmkwin/kwinrules/ruleswidget.h
+++ b/kcmkwin/kwinrules/ruleswidget.h
@@ -129,7 +129,7 @@
     explicit RulesDialog(QWidget* parent = nullptr, const char* name = nullptr);
     Rules* edit(Rules* r, const QVariantMap& info, bool show_hints);
 protected:
-    virtual void accept();
+    void accept() override;
 private Q_SLOTS:
     void displayHints();
 private:
@@ -167,7 +167,7 @@
     Q_OBJECT
 public:
     explicit ShortcutDialog(const QKeySequence& cut, QWidget* parent = nullptr);
-    virtual void accept();
+    void accept() override;
     QKeySequence shortcut() const;
 private:
     KKeySequenceWidget* widget;
diff --git a/kcmkwin/kwinscreenedges/main.h b/kcmkwin/kwinscreenedges/main.h
--- a/kcmkwin/kwinscreenedges/main.h
+++ b/kcmkwin/kwinscreenedges/main.h
@@ -48,15 +48,15 @@
 
 public:
     explicit KWinScreenEdgesConfig(QWidget* parent, const QVariantList& args);
-    ~KWinScreenEdgesConfig();
+    ~KWinScreenEdgesConfig() override;
 
 public Q_SLOTS:
     virtual void groupChanged();
-    virtual void save();
-    virtual void load();
-    virtual void defaults();
+    void save() override;
+    void load() override;
+    void defaults() override;
 protected:
-    virtual void showEvent(QShowEvent* e);
+    void showEvent(QShowEvent* e) override;
 private Q_SLOTS:
     void sanitizeCooldown();
 private:
diff --git a/kcmkwin/kwinscreenedges/monitor.h b/kcmkwin/kwinscreenedges/monitor.h
--- a/kcmkwin/kwinscreenedges/monitor.h
+++ b/kcmkwin/kwinscreenedges/monitor.h
@@ -72,7 +72,7 @@
     void changed();
     void edgeSelectionChanged(int edge, int index);
 protected:
-    virtual void resizeEvent(QResizeEvent* e);
+    void resizeEvent(QResizeEvent* e) override;
 private:
     class Corner;
     void popup(Corner* c, QPoint pos);
@@ -92,15 +92,15 @@
 {
 public:
     Corner(Monitor* m);
-    ~Corner();
+    ~Corner() override;
     void setActive(bool active);
     bool active() const;
 protected:
-    virtual void contextMenuEvent(QGraphicsSceneContextMenuEvent* e);
-    virtual void mousePressEvent(QGraphicsSceneMouseEvent* e);
-    virtual void hoverEnterEvent(QGraphicsSceneHoverEvent * e);
-    virtual void hoverLeaveEvent(QGraphicsSceneHoverEvent * e);
-    virtual void paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget = 0);
+    void contextMenuEvent(QGraphicsSceneContextMenuEvent* e) override;
+    void mousePressEvent(QGraphicsSceneMouseEvent* e) override;
+    void hoverEnterEvent(QGraphicsSceneHoverEvent * e) override;
+    void hoverLeaveEvent(QGraphicsSceneHoverEvent * e) override;
+    void paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget = 0) override;
 private:
     Monitor* monitor;
     Plasma::FrameSvg *button;
diff --git a/kcmkwin/kwinscreenedges/screenpreviewwidget.h b/kcmkwin/kwinscreenedges/screenpreviewwidget.h
--- a/kcmkwin/kwinscreenedges/screenpreviewwidget.h
+++ b/kcmkwin/kwinscreenedges/screenpreviewwidget.h
@@ -31,7 +31,7 @@
 
 public:
     ScreenPreviewWidget(QWidget *parent);
-    ~ScreenPreviewWidget();
+    ~ScreenPreviewWidget() override;
 
     void setPreview(const QPixmap &preview);
     const QPixmap preview() const;
@@ -41,9 +41,9 @@
     QRect previewRect() const;
 
 protected:
-    void resizeEvent(QResizeEvent *event);
-    void paintEvent(QPaintEvent *event);
-    virtual void dropEvent(QDropEvent *event);
+    void resizeEvent(QResizeEvent *event) override;
+    void paintEvent(QPaintEvent *event) override;
+    void dropEvent(QDropEvent *event) override;
 
 Q_SIGNALS:
     void imageDropped(const QString &);
diff --git a/kcmkwin/kwinscreenedges/touch.h b/kcmkwin/kwinscreenedges/touch.h
--- a/kcmkwin/kwinscreenedges/touch.h
+++ b/kcmkwin/kwinscreenedges/touch.h
@@ -48,14 +48,14 @@
 
 public:
     explicit KWinScreenEdgesConfig(QWidget* parent, const QVariantList& args);
-    ~KWinScreenEdgesConfig();
+    ~KWinScreenEdgesConfig() override;
 
 public Q_SLOTS:
-    virtual void save();
-    virtual void load();
-    virtual void defaults();
+    void save() override;
+    void load() override;
+    void defaults() override;
 protected:
-    virtual void showEvent(QShowEvent* e);
+    void showEvent(QShowEvent* e) override;
 private:
     KWinScreenEdgesConfigForm* m_ui;
     KSharedConfigPtr m_config;
diff --git a/kcmkwin/kwinscripts/module.h b/kcmkwin/kwinscripts/module.h
--- a/kcmkwin/kwinscripts/module.h
+++ b/kcmkwin/kwinscripts/module.h
@@ -44,10 +44,10 @@
     /**
      * Destructor.
      **/
-    ~Module();
-    virtual void load();
-    virtual void save();
-    virtual void defaults();
+    ~Module() override;
+    void load() override;
+    void save() override;
+    void defaults() override;
 
 protected Q_SLOTS:
 
diff --git a/kcmkwin/kwintabbox/layoutpreview.h b/kcmkwin/kwintabbox/layoutpreview.h
--- a/kcmkwin/kwintabbox/layoutpreview.h
+++ b/kcmkwin/kwintabbox/layoutpreview.h
@@ -38,9 +38,9 @@
     Q_OBJECT
 public:
     explicit LayoutPreview(const QString &path, QObject *parent = nullptr);
-    virtual ~LayoutPreview();
+    ~LayoutPreview() override;
 
-    virtual bool eventFilter(QObject *object, QEvent *event) override;
+    bool eventFilter(QObject *object, QEvent *event) override;
 private:
     SwitcherItem *m_item;
 };
@@ -50,11 +50,11 @@
     Q_OBJECT
 public:
     explicit ExampleClientModel(QObject *parent = nullptr);
-    virtual ~ExampleClientModel();
+    ~ExampleClientModel() override;
 
-    virtual QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const;
-    virtual int rowCount(const QModelIndex &parent = QModelIndex()) const;
-    virtual QHash<int, QByteArray> roleNames() const;
+    QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const override;
+    int rowCount(const QModelIndex &parent = QModelIndex()) const override;
+    QHash<int, QByteArray> roleNames() const override;
     Q_INVOKABLE QString longestCaption() const;
 
 private:
@@ -84,7 +84,7 @@
     Q_CLASSINFO("DefaultProperty", "item")
 public:
     SwitcherItem(QObject *parent = nullptr);
-    virtual ~SwitcherItem();
+    ~SwitcherItem() override;
 
     QAbstractItemModel *model() const;
     QRect screenGeometry() const;
diff --git a/kcmkwin/kwintabbox/main.h b/kcmkwin/kwintabbox/main.h
--- a/kcmkwin/kwintabbox/main.h
+++ b/kcmkwin/kwintabbox/main.h
@@ -54,12 +54,12 @@
 
 public:
     explicit KWinTabBoxConfig(QWidget* parent, const QVariantList& args);
-    ~KWinTabBoxConfig();
+    ~KWinTabBoxConfig() override;
 
 public Q_SLOTS:
-    virtual void save();
-    virtual void load();
-    virtual void defaults();
+    void save() override;
+    void load() override;
+    void defaults() override;
 
 private Q_SLOTS:
     void effectSelectionChanged(int index);
diff --git a/kcmkwin/kwintabbox/thumbnailitem.h b/kcmkwin/kwintabbox/thumbnailitem.h
--- a/kcmkwin/kwintabbox/thumbnailitem.h
+++ b/kcmkwin/kwintabbox/thumbnailitem.h
@@ -32,11 +32,11 @@
 {
 public:
     BrightnessSaturationShader();
-    virtual const char* vertexShader() const override;
-    virtual const char* fragmentShader() const override;
-    virtual const char*const* attributeNames() const override;
-    virtual void updateState(const RenderState& state, QSGMaterial* newMaterial, QSGMaterial* oldMaterial) override;
-    virtual void initialize() override;
+    const char* vertexShader() const override;
+    const char* fragmentShader() const override;
+    const char*const* attributeNames() const override;
+    void updateState(const RenderState& state, QSGMaterial* newMaterial, QSGMaterial* oldMaterial) override;
+    void initialize() override;
 private:
     int m_id_matrix;
     int m_id_opacity;
@@ -47,7 +47,7 @@
 class BrightnessSaturationMaterial : public QSGTextureMaterial
 {
 public:
-    virtual QSGMaterialShader* createShader() const override {
+    QSGMaterialShader* createShader() const override {
         return new BrightnessSaturationShader;
     }
     QSGMaterialType *type() const override {
@@ -67,7 +67,7 @@
     Q_PROPERTY(qreal saturation READ saturation WRITE setSaturation NOTIFY saturationChanged)
 public:
     explicit WindowThumbnailItem(QQuickItem *parent = nullptr);
-    virtual ~WindowThumbnailItem();
+    ~WindowThumbnailItem() override;
 
     qulonglong wId() const {
         return m_wId;
@@ -81,7 +81,7 @@
     void setClipTo(QQuickItem *clip);
     void setBrightness(qreal brightness);
     void setSaturation(qreal saturation);
-    virtual QSGNode *updatePaintNode(QSGNode *oldNode, UpdatePaintNodeData *updatePaintNodeData) override;
+    QSGNode *updatePaintNode(QSGNode *oldNode, UpdatePaintNodeData *updatePaintNodeData) override;
 
     enum Thumbnail {
         Konqueror = 1,
diff --git a/keyboard_input.h b/keyboard_input.h
--- a/keyboard_input.h
+++ b/keyboard_input.h
@@ -58,7 +58,7 @@
     Q_OBJECT
 public:
     explicit KeyboardInputRedirection(InputRedirection *parent);
-    virtual ~KeyboardInputRedirection();
+    ~KeyboardInputRedirection() override;
 
     void init();
 
diff --git a/keyboard_layout_switching.h b/keyboard_layout_switching.h
--- a/keyboard_layout_switching.h
+++ b/keyboard_layout_switching.h
@@ -38,7 +38,7 @@
 {
     Q_OBJECT
 public:
-    virtual ~Policy();
+    ~Policy() override;
 
     virtual QString name() const = 0;
 
diff --git a/libinput/connection.h b/libinput/connection.h
--- a/libinput/connection.h
+++ b/libinput/connection.h
@@ -48,7 +48,7 @@
     Q_OBJECT
 
 public:
-    ~Connection();
+    ~Connection() override;
 
     void setInputConfig(const KSharedConfigPtr &config) {
         m_config = config;
diff --git a/libinput/connection.cpp b/libinput/connection.cpp
--- a/libinput/connection.cpp
+++ b/libinput/connection.cpp
@@ -66,7 +66,7 @@
         );
     }
 
-    ~ConnectionAdaptor() {
+    ~ConnectionAdaptor() override {
         QDBusConnection::sessionBus().unregisterObject(QStringLiteral("/org/kde/KWin/InputDeviceManager"));
     }
 
diff --git a/libinput/device.h b/libinput/device.h
--- a/libinput/device.h
+++ b/libinput/device.h
@@ -141,7 +141,7 @@
 
 public:
     explicit Device(libinput_device *device, QObject *parent = nullptr);
-    virtual ~Device();
+    ~Device() override;
 
     bool isKeyboard() const {
         return m_keyboard;
diff --git a/libinput/events.h b/libinput/events.h
--- a/libinput/events.h
+++ b/libinput/events.h
@@ -62,7 +62,7 @@
 {
 public:
     KeyEvent(libinput_event *event);
-    virtual ~KeyEvent();
+    ~KeyEvent() override;
 
     uint32_t key() const;
     InputRedirection::KeyboardKeyState state() const;
@@ -83,7 +83,7 @@
 {
 public:
     PointerEvent(libinput_event* event, libinput_event_type type);
-    virtual ~PointerEvent();
+    ~PointerEvent() override;
 
     QPointF absolutePos() const;
     QPointF absolutePos(const QSize &size) const;
@@ -113,7 +113,7 @@
 {
 public:
     TouchEvent(libinput_event *event, libinput_event_type type);
-    virtual ~TouchEvent();
+    ~TouchEvent() override;
 
     quint32 time() const;
     QPointF absolutePos() const;
@@ -134,7 +134,7 @@
 class GestureEvent : public Event
 {
 public:
-    virtual ~GestureEvent();
+    ~GestureEvent() override;
 
     quint32 time() const;
     int fingerCount() const;
@@ -159,7 +159,7 @@
 {
 public:
     PinchGestureEvent(libinput_event *event, libinput_event_type type);
-    virtual ~PinchGestureEvent();
+    ~PinchGestureEvent() override;
 
     qreal scale() const;
     qreal angleDelta() const;
@@ -169,7 +169,7 @@
 {
 public:
     SwipeGestureEvent(libinput_event *event, libinput_event_type type);
-    virtual ~SwipeGestureEvent();
+    ~SwipeGestureEvent() override;
 };
 
 class SwitchEvent : public Event
diff --git a/libkwineffects/kwinanimationeffect.h b/libkwineffects/kwinanimationeffect.h
--- a/libkwineffects/kwinanimationeffect.h
+++ b/libkwineffects/kwinanimationeffect.h
@@ -177,9 +177,9 @@
      * after _windowClosed was connected, animations for closing windows will fail.
      **/
     AnimationEffect();
-    ~AnimationEffect();
+    ~AnimationEffect() override;
 
-    bool isActive() const;
+    bool isActive() const override;
 
     /**
      * Gets stored metadata.
@@ -208,11 +208,11 @@
     static void setMetaData(MetaType type, uint value, uint &meta );
 
     // Reimplemented from KWin::Effect.
-    QString debug(const QString &parameter) const;
-    virtual void prePaintScreen( ScreenPrePaintData& data, int time );
-    virtual void prePaintWindow( EffectWindow* w, WindowPrePaintData& data, int time );
-    virtual void paintWindow( EffectWindow* w, int mask, QRegion region, WindowPaintData& data );
-    virtual void postPaintScreen();
+    QString debug(const QString &parameter) const override;
+    void prePaintScreen( ScreenPrePaintData& data, int time ) override;
+    void prePaintWindow( EffectWindow* w, WindowPrePaintData& data, int time ) override;
+    void paintWindow( EffectWindow* w, int mask, QRegion region, WindowPaintData& data ) override;
+    void postPaintScreen() override;
 
     /**
      * Gaussian (bumper) animation curve for QEasingCurve.
diff --git a/libkwineffects/kwineffects.h b/libkwineffects/kwineffects.h
--- a/libkwineffects/kwineffects.h
+++ b/libkwineffects/kwineffects.h
@@ -382,7 +382,7 @@
      * In OpenGL based compositing, the frameworks ensures that the context is current
      * when the Effect is destroyed.
      **/
-    virtual ~Effect();
+    ~Effect() override;
 
     /**
      * Flags describing which parts of configuration have changed.
@@ -695,7 +695,7 @@
     Q_OBJECT
 public:
     EffectPluginFactory();
-    virtual ~EffectPluginFactory();
+    ~EffectPluginFactory() override;
     /**
      * Returns whether the Effect is supported.
      *
@@ -829,7 +829,7 @@
     friend class Effect;
 public:
     explicit EffectsHandler(CompositingType type);
-    virtual ~EffectsHandler();
+    ~EffectsHandler() override;
     // for use by effects
     virtual void prePaintScreen(ScreenPrePaintData& data, int time) = 0;
     virtual void paintScreen(int mask, QRegion region, ScreenPaintData& data) = 0;
@@ -2105,7 +2105,7 @@
     };
 
     explicit EffectWindow(QObject *parent = nullptr);
-    virtual ~EffectWindow();
+    ~EffectWindow() override;
 
     virtual void enablePainting(int reason) = 0;
     virtual void disablePainting(int reason) = 0;
@@ -2727,7 +2727,7 @@
     explicit WindowPaintData(EffectWindow* w);
     explicit WindowPaintData(EffectWindow* w, const QMatrix4x4 &screenProjectionMatrix);
     WindowPaintData(const WindowPaintData &other);
-    virtual ~WindowPaintData();
+    ~WindowPaintData() override;
     /**
      * Scales the window by @p scale factor.
      * Multiplies all three components by the given factor.
@@ -2927,7 +2927,7 @@
     ScreenPaintData();
     ScreenPaintData(const QMatrix4x4 &projectionMatrix, const QRect &outputGeometry = QRect());
     ScreenPaintData(const ScreenPaintData &other);
-    virtual ~ScreenPaintData();
+    ~ScreenPaintData() override;
     /**
      * Scales the screen by @p scale factor.
      * Multiplies all three components by the given factor.
diff --git a/logind.h b/logind.h
--- a/logind.h
+++ b/logind.h
@@ -34,7 +34,7 @@
 {
     Q_OBJECT
 public:
-    ~LogindIntegration();
+    ~LogindIntegration() override;
 
     bool isConnected() const {
         return m_connected;
diff --git a/main.h b/main.h
--- a/main.h
+++ b/main.h
@@ -42,7 +42,7 @@
 class XcbEventFilter : public QAbstractNativeEventFilter
 {
 public:
-    virtual bool nativeEventFilter(const QByteArray &eventType, void *message, long int *result) override;
+    bool nativeEventFilter(const QByteArray &eventType, void *message, long int *result) override;
 };
 
 class KWIN_EXPORT Application : public  QApplication
@@ -76,7 +76,7 @@
          **/
         OperationModeXwayland
     };
-    virtual ~Application();
+    ~Application() override;
 
     void setConfigLock(bool lock);
 
@@ -275,7 +275,7 @@
 {
     Q_OBJECT
 public:
-    virtual ~ApplicationWaylandAbstract() = 0;
+    ~ApplicationWaylandAbstract() override = 0;
 protected:
     friend class Xwl::Xwayland;
 
diff --git a/main_wayland.h b/main_wayland.h
--- a/main_wayland.h
+++ b/main_wayland.h
@@ -34,7 +34,7 @@
     Q_OBJECT
 public:
     ApplicationWayland(int &argc, char **argv);
-    virtual ~ApplicationWayland();
+    ~ApplicationWayland() override;
 
     void setStartXwayland(bool start) {
         m_startXWayland = start;
diff --git a/main_x11.h b/main_x11.h
--- a/main_x11.h
+++ b/main_x11.h
@@ -31,7 +31,7 @@
     Q_OBJECT
 public:
     ApplicationX11(int &argc, char **argv);
-    virtual ~ApplicationX11();
+    ~ApplicationX11() override;
 
     void setReplace(bool replace);
 
diff --git a/netinfo.h b/netinfo.h
--- a/netinfo.h
+++ b/netinfo.h
@@ -50,15 +50,15 @@
     void setActiveClient(AbstractClient *client);
 
 protected:
-    virtual void changeNumberOfDesktops(int n) override;
-    virtual void changeCurrentDesktop(int d) override;
-    virtual void changeActiveWindow(xcb_window_t w, NET::RequestSource src, xcb_timestamp_t timestamp, xcb_window_t active_window) override;
-    virtual void closeWindow(xcb_window_t w) override;
-    virtual void moveResize(xcb_window_t w, int x_root, int y_root, unsigned long direction) override;
-    virtual void moveResizeWindow(xcb_window_t w, int flags, int x, int y, int width, int height) override;
-    virtual void gotPing(xcb_window_t w, xcb_timestamp_t timestamp) override;
-    virtual void restackWindow(xcb_window_t w, RequestSource source, xcb_window_t above, int detail, xcb_timestamp_t timestamp) override;
-    virtual void changeShowingDesktop(bool showing) override;
+    void changeNumberOfDesktops(int n) override;
+    void changeCurrentDesktop(int d) override;
+    void changeActiveWindow(xcb_window_t w, NET::RequestSource src, xcb_timestamp_t timestamp, xcb_window_t active_window) override;
+    void closeWindow(xcb_window_t w) override;
+    void moveResize(xcb_window_t w, int x_root, int y_root, unsigned long direction) override;
+    void moveResizeWindow(xcb_window_t w, int flags, int x, int y, int width, int height) override;
+    void gotPing(xcb_window_t w, xcb_timestamp_t timestamp) override;
+    void restackWindow(xcb_window_t w, RequestSource source, xcb_window_t above, int detail, xcb_timestamp_t timestamp) override;
+    void changeShowingDesktop(bool showing) override;
 
 private:
     RootInfo(xcb_window_t w, const char* name, NET::Properties properties, NET::WindowTypes types,
@@ -86,9 +86,9 @@
 public:
     WinInfo(Client* c, xcb_window_t window,
             xcb_window_t rwin, NET::Properties properties, NET::Properties2 properties2);
-    virtual void changeDesktop(int desktop) override;
-    virtual void changeFullscreenMonitors(NETFullscreenMonitors topology) override;
-    virtual void changeState(NET::States state, NET::States mask) override;
+    void changeDesktop(int desktop) override;
+    void changeFullscreenMonitors(NETFullscreenMonitors topology) override;
+    void changeState(NET::States state, NET::States mask) override;
     void disable();
 
 private:
diff --git a/options.h b/options.h
--- a/options.h
+++ b/options.h
@@ -188,7 +188,7 @@
 public:
 
     explicit Options(QObject *parent = NULL);
-    ~Options();
+    ~Options() override;
 
     void updateSettings();
 
diff --git a/orientation_sensor.h b/orientation_sensor.h
--- a/orientation_sensor.h
+++ b/orientation_sensor.h
@@ -39,7 +39,7 @@
     Q_PROPERTY(bool userEnabled READ isUserEnabled WRITE setUserEnabled NOTIFY userEnabledChanged)
 public:
     explicit OrientationSensor(QObject *parent = nullptr);
-    ~OrientationSensor();
+    ~OrientationSensor() override;
 
     void setEnabled(bool enabled);
 
diff --git a/outline.h b/outline.h
--- a/outline.h
+++ b/outline.h
@@ -50,7 +50,7 @@
     Q_PROPERTY(QRect unifiedGeometry READ unifiedGeometry NOTIFY unifiedGeometryChanged)
     Q_PROPERTY(bool active READ isActive NOTIFY activeChanged)
 public:
-    ~Outline();
+    ~Outline() override;
 
     /**
      * Set the outline geometry.
@@ -144,9 +144,9 @@
 {
 public:
     CompositedOutlineVisual(Outline *outline);
-    virtual ~CompositedOutlineVisual();
-    virtual void show();
-    virtual void hide();
+    ~CompositedOutlineVisual() override;
+    void show() override;
+    void hide() override;
 private:
     QScopedPointer<QQmlContext> m_qmlContext;
     QScopedPointer<QQmlComponent> m_qmlComponent;
diff --git a/outputscreens.h b/outputscreens.h
--- a/outputscreens.h
+++ b/outputscreens.h
@@ -35,12 +35,12 @@
     Q_OBJECT
 public:
     OutputScreens(Platform *platform, QObject *parent = nullptr);
-    virtual ~OutputScreens();
+    ~OutputScreens() override;
 
     void init() override;
     QString name(int screen) const override;
-    bool isInternal(int screen) const;
-    QSizeF physicalSize(int screen) const;
+    bool isInternal(int screen) const override;
+    QSizeF physicalSize(int screen) const override;
     QRect geometry(int screen) const override;
     QSize size(int screen) const override;
     qreal scale(int screen) const override;
diff --git a/platform.h b/platform.h
--- a/platform.h
+++ b/platform.h
@@ -80,7 +80,7 @@
 {
     Q_OBJECT
 public:
-    virtual ~Platform();
+    ~Platform() override;
 
     virtual void init() = 0;
     virtual Screens *createScreens(QObject *parent = nullptr);
diff --git a/platformsupport/scenes/opengl/abstract_egl_backend.h b/platformsupport/scenes/opengl/abstract_egl_backend.h
--- a/platformsupport/scenes/opengl/abstract_egl_backend.h
+++ b/platformsupport/scenes/opengl/abstract_egl_backend.h
@@ -43,7 +43,7 @@
 {
     Q_OBJECT
 public:
-    virtual ~AbstractEglBackend();
+    ~AbstractEglBackend() override;
     bool makeCurrent() override;
     void doneCurrent() override;
 
@@ -90,7 +90,7 @@
 class KWIN_EXPORT AbstractEglTexture : public SceneOpenGLTexturePrivate
 {
 public:
-    virtual ~AbstractEglTexture();
+    ~AbstractEglTexture() override;
     bool loadTexture(WindowPixmap *pixmap) override;
     void updateTexture(WindowPixmap *pixmap) override;
     OpenGLBackend *backend() override;
diff --git a/plugins/idletime/poller.h b/plugins/idletime/poller.h
--- a/plugins/idletime/poller.h
+++ b/plugins/idletime/poller.h
@@ -42,7 +42,7 @@
 
 public:
     Poller(QObject *parent = 0);
-    virtual ~Poller();
+    ~Poller() override;
 
     bool isAvailable() override;
     bool setUpPoller() override;
diff --git a/plugins/kdecorations/aurorae/src/aurorae.h b/plugins/kdecorations/aurorae/src/aurorae.h
--- a/plugins/kdecorations/aurorae/src/aurorae.h
+++ b/plugins/kdecorations/aurorae/src/aurorae.h
@@ -48,7 +48,7 @@
     Q_PROPERTY(KDecoration2::DecoratedClient* client READ clientPointer CONSTANT)
 public:
     explicit Decoration(QObject *parent = nullptr, const QVariantList &args = QVariantList());
-    virtual ~Decoration();
+    ~Decoration() override;
 
     void paint(QPainter *painter, const QRect &repaintRegion) override;
 
diff --git a/plugins/kdecorations/aurorae/src/colorhelper.h b/plugins/kdecorations/aurorae/src/colorhelper.h
--- a/plugins/kdecorations/aurorae/src/colorhelper.h
+++ b/plugins/kdecorations/aurorae/src/colorhelper.h
@@ -37,7 +37,7 @@
     Q_PROPERTY(qreal contrast READ contrast CONSTANT)
 public:
     explicit ColorHelper(QObject *parent = nullptr);
-    ~ColorHelper();
+    ~ColorHelper() override;
     /**
      * This enumeration describes the color shade being selected from the given
      * set.
diff --git a/plugins/kdecorations/aurorae/src/decorationoptions.h b/plugins/kdecorations/aurorae/src/decorationoptions.h
--- a/plugins/kdecorations/aurorae/src/decorationoptions.h
+++ b/plugins/kdecorations/aurorae/src/decorationoptions.h
@@ -215,7 +215,7 @@
         DecorationButtonExplicitSpacer
     };
     explicit DecorationOptions(QObject *parent = nullptr);
-    virtual ~DecorationOptions();
+    ~DecorationOptions() override;
 
     QColor titleBarColor() const;
     QColor titleBarBlendColor() const;
@@ -256,7 +256,7 @@
     Q_PROPERTY(int bottom READ bottom WRITE setBottom NOTIFY bottomChanged)
 public:
     Borders(QObject *parent = nullptr);
-    virtual ~Borders();
+    ~Borders() override;
     int left() const;
     int right() const;
     int top() const;
diff --git a/plugins/kdecorations/aurorae/src/decorationplugin.h b/plugins/kdecorations/aurorae/src/decorationplugin.h
--- a/plugins/kdecorations/aurorae/src/decorationplugin.h
+++ b/plugins/kdecorations/aurorae/src/decorationplugin.h
@@ -23,7 +23,7 @@
     Q_PLUGIN_METADATA(IID "org.kde.kwin.decoration")
     Q_OBJECT
 public:
-    void registerTypes(const char *uri);
+    void registerTypes(const char *uri) override;
 };
 
 #endif
diff --git a/plugins/kdecorations/aurorae/src/lib/auroraetheme.h b/plugins/kdecorations/aurorae/src/lib/auroraetheme.h
--- a/plugins/kdecorations/aurorae/src/lib/auroraetheme.h
+++ b/plugins/kdecorations/aurorae/src/lib/auroraetheme.h
@@ -116,7 +116,7 @@
     Q_PROPERTY(Qt::Alignment verticalAlignment READ verticalAlignment NOTIFY themeChanged)
 public:
     explicit AuroraeTheme(QObject* parent = nullptr);
-    virtual ~AuroraeTheme();
+    ~AuroraeTheme() override;
     // TODO: KSharedConfigPtr
     void loadTheme(const QString &name, const KConfig &config);
     bool isValid() const;
diff --git a/plugins/kdecorations/aurorae/themes/plastik/code/plastikbutton.h b/plugins/kdecorations/aurorae/themes/plastik/code/plastikbutton.h
--- a/plugins/kdecorations/aurorae/themes/plastik/code/plastikbutton.h
+++ b/plugins/kdecorations/aurorae/themes/plastik/code/plastikbutton.h
@@ -26,7 +26,7 @@
 {
 public:
     explicit PlastikButtonProvider();
-    virtual QPixmap requestPixmap(const QString &id, QSize *size, const QSize &requestedSize);
+    QPixmap requestPixmap(const QString &id, QSize *size, const QSize &requestedSize) override;
 
 private:
     enum ButtonIcon {
diff --git a/plugins/kdecorations/aurorae/themes/plastik/code/plastikplugin.h b/plugins/kdecorations/aurorae/themes/plastik/code/plastikplugin.h
--- a/plugins/kdecorations/aurorae/themes/plastik/code/plastikplugin.h
+++ b/plugins/kdecorations/aurorae/themes/plastik/code/plastikplugin.h
@@ -24,8 +24,8 @@
     Q_PLUGIN_METADATA(IID "org.kde.kwin.decorations.plastik")
     Q_OBJECT
 public:
-    virtual void registerTypes(const char *uri) override;
-    virtual void initializeEngine(QQmlEngine *engine, const char *uri) override;
+    void registerTypes(const char *uri) override;
+    void initializeEngine(QQmlEngine *engine, const char *uri) override;
 };
 
 #endif // PLASTIK_PLUGIN_H
diff --git a/plugins/kglobalaccel/kglobalaccel_plugin.h b/plugins/kglobalaccel/kglobalaccel_plugin.h
--- a/plugins/kglobalaccel/kglobalaccel_plugin.h
+++ b/plugins/kglobalaccel/kglobalaccel_plugin.h
@@ -32,7 +32,7 @@
 
 public:
     KGlobalAccelImpl(QObject *parent = 0);
-    virtual ~KGlobalAccelImpl();
+    ~KGlobalAccelImpl() override;
 
     bool grabKey(int key, bool grab) override;
     void setEnabled(bool) override;
diff --git a/plugins/platforms/drm/drm_backend.h b/plugins/platforms/drm/drm_backend.h
--- a/plugins/platforms/drm/drm_backend.h
+++ b/plugins/platforms/drm/drm_backend.h
@@ -73,7 +73,7 @@
     Q_PLUGIN_METADATA(IID "org.kde.kwin.Platform" FILE "drm.json")
 public:
     explicit DrmBackend(QObject *parent = nullptr);
-    virtual ~DrmBackend();
+    ~DrmBackend() override;
 
     void configurationChangeRequested(KWayland::Server::OutputConfigurationInterface *config) override;
     Screens *createScreens(QObject *parent = nullptr) override;
diff --git a/plugins/platforms/drm/drm_buffer.h b/plugins/platforms/drm/drm_buffer.h
--- a/plugins/platforms/drm/drm_buffer.h
+++ b/plugins/platforms/drm/drm_buffer.h
@@ -58,7 +58,7 @@
 {
 public:
     DrmDumbBuffer(int fd, const QSize &size);
-    ~DrmDumbBuffer();
+    ~DrmDumbBuffer() override;
 
     bool needsModeChange(DrmBuffer *b) const override;
 
diff --git a/plugins/platforms/drm/drm_buffer_gbm.h b/plugins/platforms/drm/drm_buffer_gbm.h
--- a/plugins/platforms/drm/drm_buffer_gbm.h
+++ b/plugins/platforms/drm/drm_buffer_gbm.h
@@ -36,7 +36,7 @@
 {
 public:
     DrmSurfaceBuffer(int fd, const std::shared_ptr<GbmSurface> &surface);
-    ~DrmSurfaceBuffer();
+    ~DrmSurfaceBuffer() override;
 
     bool needsModeChange(DrmBuffer *b) const override {
         if (DrmSurfaceBuffer *sb = dynamic_cast<DrmSurfaceBuffer*>(b)) {
diff --git a/plugins/platforms/drm/drm_inputeventfilter.h b/plugins/platforms/drm/drm_inputeventfilter.h
--- a/plugins/platforms/drm/drm_inputeventfilter.h
+++ b/plugins/platforms/drm/drm_inputeventfilter.h
@@ -32,7 +32,7 @@
 {
 public:
     DpmsInputEventFilter(DrmBackend *backend);
-    ~DpmsInputEventFilter();
+    ~DpmsInputEventFilter() override;
 
     bool pointerEvent(QMouseEvent *event, quint32 nativeButton) override;
     bool wheelEvent(QWheelEvent *event) override;
diff --git a/plugins/platforms/drm/drm_object_connector.h b/plugins/platforms/drm/drm_object_connector.h
--- a/plugins/platforms/drm/drm_object_connector.h
+++ b/plugins/platforms/drm/drm_object_connector.h
@@ -30,9 +30,9 @@
 public:
     DrmConnector(uint32_t connector_id, int fd);
 
-    virtual ~DrmConnector();
+    ~DrmConnector() override;
 
-    bool atomicInit();
+    bool atomicInit() override;
 
     enum class PropertyIndex {
         CrtcId = 0,
@@ -43,7 +43,7 @@
         return m_encoders;
     }
     
-    bool initProps();
+    bool initProps() override;
     bool isConnected();
 
 
diff --git a/plugins/platforms/drm/drm_object_crtc.h b/plugins/platforms/drm/drm_object_crtc.h
--- a/plugins/platforms/drm/drm_object_crtc.h
+++ b/plugins/platforms/drm/drm_object_crtc.h
@@ -35,17 +35,17 @@
 public:
     DrmCrtc(uint32_t crtc_id, DrmBackend *backend, int resIndex);
 
-    virtual ~DrmCrtc();
+    ~DrmCrtc() override;
 
-    bool atomicInit();
+    bool atomicInit() override;
 
     enum class PropertyIndex {
         ModeId = 0,
         Active,
         Count
     };
 
-    bool initProps();
+    bool initProps() override;
 
     int resIndex() const {
         return m_resIndex;
diff --git a/plugins/platforms/drm/drm_object_plane.h b/plugins/platforms/drm/drm_object_plane.h
--- a/plugins/platforms/drm/drm_object_plane.h
+++ b/plugins/platforms/drm/drm_object_plane.h
@@ -34,7 +34,7 @@
 public:
     DrmPlane(uint32_t plane_id, int fd);
 
-    ~DrmPlane();
+    ~DrmPlane() override;
 
     enum class PropertyIndex {
         Type = 0,
@@ -69,8 +69,8 @@
     };
     Q_DECLARE_FLAGS(Transformations, Transformation);
 
-    bool atomicInit();
-    bool initProps();
+    bool atomicInit() override;
+    bool initProps() override;
     TypeIndex type();
 
     bool isCrtcSupported(int resIndex) const {
@@ -93,7 +93,7 @@
     void setTransformation(Transformations t);
     Transformations transformation();
 
-    bool atomicPopulate(drmModeAtomicReq *req);
+    bool atomicPopulate(drmModeAtomicReq *req) override;
     void flipBuffer();
     void flipBufferWithDelete();
 
diff --git a/plugins/platforms/drm/egl_gbm_backend.h b/plugins/platforms/drm/egl_gbm_backend.h
--- a/plugins/platforms/drm/egl_gbm_backend.h
+++ b/plugins/platforms/drm/egl_gbm_backend.h
@@ -41,7 +41,7 @@
     Q_OBJECT
 public:
     EglGbmBackend(DrmBackend *b);
-    virtual ~EglGbmBackend();
+    ~EglGbmBackend() override;
     void screenGeometryChanged(const QSize &size) override;
     SceneOpenGLTexturePrivate *createBackendTexture(SceneOpenGLTexture *texture) override;
     QRegion prepareRenderingFrame() override;
@@ -89,7 +89,7 @@
 class EglGbmTexture : public AbstractEglTexture
 {
 public:
-    virtual ~EglGbmTexture();
+    ~EglGbmTexture() override;
 
 private:
     friend class EglGbmBackend;
diff --git a/plugins/platforms/drm/egl_stream_backend.h b/plugins/platforms/drm/egl_stream_backend.h
--- a/plugins/platforms/drm/egl_stream_backend.h
+++ b/plugins/platforms/drm/egl_stream_backend.h
@@ -40,7 +40,7 @@
     Q_OBJECT
 public:
     EglStreamBackend(DrmBackend *b);
-    virtual ~EglStreamBackend();
+    ~EglStreamBackend() override;
     void screenGeometryChanged(const QSize &size) override;
     SceneOpenGLTexturePrivate *createBackendTexture(SceneOpenGLTexture *texture) override;
     QRegion prepareRenderingFrame() override;
@@ -95,7 +95,7 @@
 class EglStreamTexture : public AbstractEglTexture
 {
 public:
-    virtual ~EglStreamTexture();
+    ~EglStreamTexture() override;
     bool loadTexture(WindowPixmap *pixmap) override;
     void updateTexture(WindowPixmap *pixmap) override;
 
diff --git a/plugins/platforms/drm/remoteaccess_manager.h b/plugins/platforms/drm/remoteaccess_manager.h
--- a/plugins/platforms/drm/remoteaccess_manager.h
+++ b/plugins/platforms/drm/remoteaccess_manager.h
@@ -43,7 +43,7 @@
     Q_OBJECT
 public:
     explicit RemoteAccessManager(QObject *parent = nullptr);
-    virtual ~RemoteAccessManager();
+    ~RemoteAccessManager() override;
 
     void passBuffer(DrmOutput *output, DrmBuffer *buffer);
 
diff --git a/plugins/platforms/drm/scene_qpainter_drm_backend.h b/plugins/platforms/drm/scene_qpainter_drm_backend.h
--- a/plugins/platforms/drm/scene_qpainter_drm_backend.h
+++ b/plugins/platforms/drm/scene_qpainter_drm_backend.h
@@ -35,7 +35,7 @@
     Q_OBJECT
 public:
     DrmQPainterBackend(DrmBackend *backend);
-    virtual ~DrmQPainterBackend();
+    ~DrmQPainterBackend() override;
 
     QImage *buffer() override;
     QImage *bufferForScreen(int screenId) override;
diff --git a/plugins/platforms/drm/screens_drm.h b/plugins/platforms/drm/screens_drm.h
--- a/plugins/platforms/drm/screens_drm.h
+++ b/plugins/platforms/drm/screens_drm.h
@@ -30,7 +30,7 @@
     Q_OBJECT
 public:
     DrmScreens(DrmBackend *backend, QObject *parent = nullptr);
-    virtual ~DrmScreens();
+    ~DrmScreens() override;
 
     bool supportsTransformations(int screen) const override;
 
diff --git a/plugins/platforms/fbdev/fb_backend.h b/plugins/platforms/fbdev/fb_backend.h
--- a/plugins/platforms/fbdev/fb_backend.h
+++ b/plugins/platforms/fbdev/fb_backend.h
@@ -35,7 +35,7 @@
 
 public:
     FramebufferOutput(QObject *parent = nullptr) : AbstractWaylandOutput(parent) {}
-    virtual ~FramebufferOutput() = default;
+    ~FramebufferOutput() override = default;
 
     QSize pixelSize() const override {
         return m_pixelSize;
@@ -59,7 +59,7 @@
     Q_PLUGIN_METADATA(IID "org.kde.kwin.Platform" FILE "fbdev.json")
 public:
     explicit FramebufferBackend(QObject *parent = nullptr);
-    virtual ~FramebufferBackend();
+    ~FramebufferBackend() override;
 
     Screens *createScreens(QObject *parent = nullptr) override;
     QPainterBackend *createQPainterBackend() override;
diff --git a/plugins/platforms/fbdev/scene_qpainter_fb_backend.h b/plugins/platforms/fbdev/scene_qpainter_fb_backend.h
--- a/plugins/platforms/fbdev/scene_qpainter_fb_backend.h
+++ b/plugins/platforms/fbdev/scene_qpainter_fb_backend.h
@@ -33,7 +33,7 @@
     Q_OBJECT
 public:
     FramebufferQPainterBackend(FramebufferBackend *backend);
-    virtual ~FramebufferQPainterBackend();
+    ~FramebufferQPainterBackend() override;
 
     QImage *buffer() override;
     QImage *bufferForScreen(int screenId) override;
diff --git a/plugins/platforms/virtual/egl_gbm_backend.h b/plugins/platforms/virtual/egl_gbm_backend.h
--- a/plugins/platforms/virtual/egl_gbm_backend.h
+++ b/plugins/platforms/virtual/egl_gbm_backend.h
@@ -34,7 +34,7 @@
 {
 public:
     EglGbmBackend(VirtualBackend *b);
-    virtual ~EglGbmBackend();
+    ~EglGbmBackend() override;
     void screenGeometryChanged(const QSize &size) override;
     SceneOpenGLTexturePrivate *createBackendTexture(SceneOpenGLTexture *texture) override;
     QRegion prepareRenderingFrame() override;
@@ -62,7 +62,7 @@
 class EglGbmTexture : public AbstractEglTexture
 {
 public:
-    virtual ~EglGbmTexture();
+    ~EglGbmTexture() override;
 
 private:
     friend class EglGbmBackend;
diff --git a/plugins/platforms/virtual/scene_qpainter_virtual_backend.h b/plugins/platforms/virtual/scene_qpainter_virtual_backend.h
--- a/plugins/platforms/virtual/scene_qpainter_virtual_backend.h
+++ b/plugins/platforms/virtual/scene_qpainter_virtual_backend.h
@@ -35,7 +35,7 @@
     Q_OBJECT
 public:
     VirtualQPainterBackend(VirtualBackend *backend);
-    virtual ~VirtualQPainterBackend();
+    ~VirtualQPainterBackend() override;
 
     QImage *buffer() override;
     QImage *bufferForScreen(int screenId) override;
diff --git a/plugins/platforms/virtual/screens_virtual.h b/plugins/platforms/virtual/screens_virtual.h
--- a/plugins/platforms/virtual/screens_virtual.h
+++ b/plugins/platforms/virtual/screens_virtual.h
@@ -31,7 +31,7 @@
     Q_OBJECT
 public:
     VirtualScreens(VirtualBackend *backend, QObject *parent = nullptr);
-    virtual ~VirtualScreens();
+    ~VirtualScreens() override;
     void init() override;
 
 private:
diff --git a/plugins/platforms/virtual/virtual_backend.h b/plugins/platforms/virtual/virtual_backend.h
--- a/plugins/platforms/virtual/virtual_backend.h
+++ b/plugins/platforms/virtual/virtual_backend.h
@@ -40,7 +40,7 @@
 
 public:
     VirtualBackend(QObject *parent = nullptr);
-    virtual ~VirtualBackend();
+    ~VirtualBackend() override;
     void init() override;
 
     bool saveFrames() const {
diff --git a/plugins/platforms/virtual/virtual_output.h b/plugins/platforms/virtual/virtual_output.h
--- a/plugins/platforms/virtual/virtual_output.h
+++ b/plugins/platforms/virtual/virtual_output.h
@@ -35,7 +35,7 @@
 
 public:
     VirtualOutput(QObject *parent = nullptr);
-    virtual ~VirtualOutput();
+    ~VirtualOutput() override;
 
     QSize pixelSize() const override;
 
diff --git a/plugins/platforms/wayland/egl_wayland_backend.h b/plugins/platforms/wayland/egl_wayland_backend.h
--- a/plugins/platforms/wayland/egl_wayland_backend.h
+++ b/plugins/platforms/wayland/egl_wayland_backend.h
@@ -42,7 +42,7 @@
     Q_OBJECT
 public:
     EglWaylandOutput(WaylandOutput *output, QObject *parent = nullptr);
-    ~EglWaylandOutput() = default;
+    ~EglWaylandOutput() override = default;
 
     bool init(EglWaylandBackend *backend);
     void updateSize(const QSize &size);
@@ -77,14 +77,14 @@
     Q_OBJECT
 public:
     EglWaylandBackend(WaylandBackend *b);
-    virtual ~EglWaylandBackend();
+    ~EglWaylandBackend() override;
     void screenGeometryChanged(const QSize &size) override;
     SceneOpenGLTexturePrivate *createBackendTexture(SceneOpenGLTexture *texture) override;
     QRegion prepareRenderingFrame() override;
     QRegion prepareRenderingForScreen(int screenId) override;
     void endRenderingFrame(const QRegion &renderedRegion, const QRegion &damagedRegion) override;
     void endRenderingFrameForScreen(int screenId, const QRegion &damage, const QRegion &damagedRegion) override;
-    virtual bool usesOverlayWindow() const override;
+    bool usesOverlayWindow() const override;
     bool perScreenRendering() const override;
     void init() override;
 
@@ -119,7 +119,7 @@
 class EglWaylandTexture : public AbstractEglTexture
 {
 public:
-    virtual ~EglWaylandTexture();
+    ~EglWaylandTexture() override;
 
 private:
     friend class EglWaylandBackend;
diff --git a/plugins/platforms/wayland/scene_qpainter_wayland_backend.h b/plugins/platforms/wayland/scene_qpainter_wayland_backend.h
--- a/plugins/platforms/wayland/scene_qpainter_wayland_backend.h
+++ b/plugins/platforms/wayland/scene_qpainter_wayland_backend.h
@@ -49,7 +49,7 @@
     Q_OBJECT
 public:
     WaylandQPainterOutput(WaylandOutput *output, QObject *parent = nullptr);
-    ~WaylandQPainterOutput();
+    ~WaylandQPainterOutput() override;
 
     bool init(KWayland::Client::ShmPool *pool);
     void updateSize(const QSize &size);
@@ -73,17 +73,17 @@
     Q_OBJECT
 public:
     explicit WaylandQPainterBackend(WaylandBackend *b);
-    virtual ~WaylandQPainterBackend();
+    ~WaylandQPainterBackend() override;
 
-    virtual bool usesOverlayWindow() const override;
+    bool usesOverlayWindow() const override;
 
-    virtual QImage *buffer() override;
+    QImage *buffer() override;
     QImage *bufferForScreen(int screenId) override;
 
-    virtual void present(int mask, const QRegion& damage) override;
-    virtual void prepareRenderingFrame() override;
+    void present(int mask, const QRegion& damage) override;
+    void prepareRenderingFrame() override;
 
-    virtual bool needsFullRepaint() const override;
+    bool needsFullRepaint() const override;
     bool perScreenRendering() const override;
 
 private:
diff --git a/plugins/platforms/wayland/wayland_backend.h b/plugins/platforms/wayland/wayland_backend.h
--- a/plugins/platforms/wayland/wayland_backend.h
+++ b/plugins/platforms/wayland/wayland_backend.h
@@ -81,7 +81,7 @@
     Q_OBJECT
 public:
     explicit WaylandCursor(WaylandBackend *backend);
-    virtual ~WaylandCursor();
+    ~WaylandCursor() override;
 
     virtual void init();
     virtual void move(const QPointF &globalPosition) {
@@ -113,7 +113,7 @@
     Q_OBJECT
 public:
     explicit WaylandSubSurfaceCursor(WaylandBackend *backend);
-    virtual ~WaylandSubSurfaceCursor();
+    ~WaylandSubSurfaceCursor() override;
 
     void init() override;
 
@@ -134,7 +134,7 @@
     Q_OBJECT
 public:
     WaylandSeat(wl_seat *seat, WaylandBackend *backend);
-    virtual ~WaylandSeat();
+    ~WaylandSeat() override;
 
     KWayland::Client::Pointer *pointer() const {
         return m_pointer;
@@ -177,7 +177,7 @@
     Q_PLUGIN_METADATA(IID "org.kde.kwin.Platform" FILE "wayland.json")
 public:
     explicit WaylandBackend(QObject *parent = nullptr);
-    virtual ~WaylandBackend();
+    ~WaylandBackend() override;
     void init() override;
     wl_display *display();
     KWayland::Client::Compositor *compositor();
diff --git a/plugins/platforms/wayland/wayland_output.h b/plugins/platforms/wayland/wayland_output.h
--- a/plugins/platforms/wayland/wayland_output.h
+++ b/plugins/platforms/wayland/wayland_output.h
@@ -51,7 +51,7 @@
     Q_OBJECT
 public:
     explicit WaylandOutput(KWayland::Client::Surface *surface, QObject *parent = nullptr);
-    ~WaylandOutput();
+    ~WaylandOutput() override;
 
     virtual void lockPointer(KWayland::Client::Pointer *pointer, bool lock) {
         Q_UNUSED(pointer)
@@ -97,7 +97,7 @@
     ShellOutput(KWayland::Client::Surface *surface,
                 KWayland::Client::Shell *shell,
                 WaylandBackend *backend);
-    ~ShellOutput();
+    ~ShellOutput() override;
 
 private:
     KWayland::Client::ShellSurface *m_shellSurface = nullptr;
@@ -109,7 +109,7 @@
     XdgShellOutput(KWayland::Client::Surface *surface,
                    KWayland::Client::XdgShell *xdgShell,
                    WaylandBackend *backend, int number);
-    ~XdgShellOutput();
+    ~XdgShellOutput() override;
 
     void lockPointer(KWayland::Client::Pointer *pointer, bool lock) override;
 
diff --git a/plugins/platforms/x11/common/eglonxbackend.h b/plugins/platforms/x11/common/eglonxbackend.h
--- a/plugins/platforms/x11/common/eglonxbackend.h
+++ b/plugins/platforms/x11/common/eglonxbackend.h
@@ -35,21 +35,21 @@
 public:
     EglOnXBackend(Display *display);
     explicit EglOnXBackend(xcb_connection_t *connection, Display *display, xcb_window_t rootWindow, int screenNumber, xcb_window_t renderingWindow);
-    virtual ~EglOnXBackend();
-    virtual void screenGeometryChanged(const QSize &size);
-    virtual SceneOpenGLTexturePrivate *createBackendTexture(SceneOpenGLTexture *texture) override;
-    virtual QRegion prepareRenderingFrame();
-    virtual void endRenderingFrame(const QRegion &damage, const QRegion &damagedRegion);
-    virtual OverlayWindow* overlayWindow() override;
-    virtual bool usesOverlayWindow() const override;
+    ~EglOnXBackend() override;
+    void screenGeometryChanged(const QSize &size) override;
+    SceneOpenGLTexturePrivate *createBackendTexture(SceneOpenGLTexture *texture) override;
+    QRegion prepareRenderingFrame() override;
+    void endRenderingFrame(const QRegion &damage, const QRegion &damagedRegion) override;
+    OverlayWindow* overlayWindow() override;
+    bool usesOverlayWindow() const override;
     void init() override;
 
     bool isX11TextureFromPixmapSupported() const {
         return m_x11TextureFromPixmapSupported;
     }
 
 protected:
-    virtual void present();
+    void present() override;
     void presentSurface(EGLSurface surface, const QRegion &damage, const QRect &screenGeometry);
     virtual bool createSurfaces();
     EGLSurface createSurface(xcb_window_t window);
@@ -92,8 +92,8 @@
 class EglTexture : public AbstractEglTexture
 {
 public:
-    virtual ~EglTexture();
-    virtual void onDamage();
+    ~EglTexture() override;
+    void onDamage() override;
     bool loadTexture(WindowPixmap *pixmap) override;
 
 private:
diff --git a/plugins/platforms/x11/standalone/edge.h b/plugins/platforms/x11/standalone/edge.h
--- a/plugins/platforms/x11/standalone/edge.h
+++ b/plugins/platforms/x11/standalone/edge.h
@@ -39,7 +39,7 @@
     Q_OBJECT
 public:
     explicit WindowBasedEdge(ScreenEdges *parent);
-    virtual ~WindowBasedEdge();
+    ~WindowBasedEdge() override;
 
     quint32 window() const override;
     /**
@@ -49,12 +49,12 @@
     quint32 approachWindow() const override;
 
 protected:
-    virtual void doGeometryUpdate();
-    virtual void doActivate() override;
-    virtual void doDeactivate() override;
-    virtual void doStartApproaching();
-    virtual void doStopApproaching();
-    virtual void doUpdateBlocking();
+    void doGeometryUpdate() override;
+    void doActivate() override;
+    void doDeactivate() override;
+    void doStartApproaching() override;
+    void doStopApproaching() override;
+    void doUpdateBlocking() override;
 
 private:
     void createWindow();
diff --git a/plugins/platforms/x11/standalone/glxbackend.h b/plugins/platforms/x11/standalone/glxbackend.h
--- a/plugins/platforms/x11/standalone/glxbackend.h
+++ b/plugins/platforms/x11/standalone/glxbackend.h
@@ -69,19 +69,19 @@
 {
 public:
     GlxBackend(Display *display);
-    virtual ~GlxBackend();
-    virtual void screenGeometryChanged(const QSize &size);
-    virtual SceneOpenGLTexturePrivate *createBackendTexture(SceneOpenGLTexture *texture) override;
-    virtual QRegion prepareRenderingFrame();
-    virtual void endRenderingFrame(const QRegion &damage, const QRegion &damagedRegion);
-    virtual bool makeCurrent() override;
-    virtual void doneCurrent() override;
-    virtual OverlayWindow* overlayWindow() override;
-    virtual bool usesOverlayWindow() const override;
+    ~GlxBackend() override;
+    void screenGeometryChanged(const QSize &size) override;
+    SceneOpenGLTexturePrivate *createBackendTexture(SceneOpenGLTexture *texture) override;
+    QRegion prepareRenderingFrame() override;
+    void endRenderingFrame(const QRegion &damage, const QRegion &damagedRegion) override;
+    bool makeCurrent() override;
+    void doneCurrent() override;
+    OverlayWindow* overlayWindow() override;
+    bool usesOverlayWindow() const override;
     void init() override;
 
 protected:
-    virtual void present();
+    void present() override;
 
 private:
     bool initBuffer();
@@ -129,10 +129,10 @@
 class GlxTexture : public SceneOpenGLTexturePrivate
 {
 public:
-    virtual ~GlxTexture();
-    virtual void onDamage();
-    virtual bool loadTexture(WindowPixmap *pixmap) override;
-    virtual OpenGLBackend *backend();
+    ~GlxTexture() override;
+    void onDamage() override;
+    bool loadTexture(WindowPixmap *pixmap) override;
+    OpenGLBackend *backend() override;
 
 private:
     friend class GlxBackend;
diff --git a/plugins/platforms/x11/standalone/non_composited_outline.h b/plugins/platforms/x11/standalone/non_composited_outline.h
--- a/plugins/platforms/x11/standalone/non_composited_outline.h
+++ b/plugins/platforms/x11/standalone/non_composited_outline.h
@@ -29,9 +29,9 @@
 {
 public:
     NonCompositedOutlineVisual(Outline *outline);
-    virtual ~NonCompositedOutlineVisual();
-    virtual void show();
-    virtual void hide();
+    ~NonCompositedOutlineVisual() override;
+    void show() override;
+    void hide() override;
 
 private:
     // TODO: variadic template arguments for adding method arguments
diff --git a/plugins/platforms/x11/standalone/overlaywindow_x11.h b/plugins/platforms/x11/standalone/overlaywindow_x11.h
--- a/plugins/platforms/x11/standalone/overlaywindow_x11.h
+++ b/plugins/platforms/x11/standalone/overlaywindow_x11.h
@@ -28,7 +28,7 @@
 class KWIN_EXPORT OverlayWindowX11 : public OverlayWindow, public X11EventFilter {
 public:
     OverlayWindowX11();
-    ~OverlayWindowX11();
+    ~OverlayWindowX11() override;
     /// Creates XComposite overlay window, call initOverlay() afterwards
     bool create() override;
     /// Init overlay and the destination window in it
diff --git a/plugins/platforms/x11/standalone/screens_xrandr.h b/plugins/platforms/x11/standalone/screens_xrandr.h
--- a/plugins/platforms/x11/standalone/screens_xrandr.h
+++ b/plugins/platforms/x11/standalone/screens_xrandr.h
@@ -32,7 +32,7 @@
     Q_OBJECT
 public:
     XRandRScreens(X11StandalonePlatform *backend, QObject *parent = nullptr);
-    virtual ~XRandRScreens();
+    ~XRandRScreens() override;
     void init() override;
 
     QSize displaySize() const override;
diff --git a/plugins/platforms/x11/standalone/windowselector.h b/plugins/platforms/x11/standalone/windowselector.h
--- a/plugins/platforms/x11/standalone/windowselector.h
+++ b/plugins/platforms/x11/standalone/windowselector.h
@@ -40,7 +40,7 @@
 public:
 
     WindowSelector();
-    ~WindowSelector();
+    ~WindowSelector() override;
 
     void start(std::function<void(KWin::Toplevel*)> callback, const QByteArray &cursorName);
     void start(std::function<void (const QPoint &)> callback);
diff --git a/plugins/platforms/x11/standalone/x11_decoration_renderer.h b/plugins/platforms/x11/standalone/x11_decoration_renderer.h
--- a/plugins/platforms/x11/standalone/x11_decoration_renderer.h
+++ b/plugins/platforms/x11/standalone/x11_decoration_renderer.h
@@ -37,7 +37,7 @@
     Q_OBJECT
 public:
     explicit X11Renderer(DecoratedClientImpl *client);
-    virtual ~X11Renderer();
+    ~X11Renderer() override;
 
     void reparent(Deleted *deleted) override;
 
diff --git a/plugins/platforms/x11/standalone/x11_output.h b/plugins/platforms/x11/standalone/x11_output.h
--- a/plugins/platforms/x11/standalone/x11_output.h
+++ b/plugins/platforms/x11/standalone/x11_output.h
@@ -40,7 +40,7 @@
 
 public:
     explicit X11Output(QObject *parent = nullptr);
-    virtual ~X11Output() = default;
+    ~X11Output() override = default;
 
     QString name() const override;
     void setName(QString set);
diff --git a/plugins/platforms/x11/standalone/x11_platform.h b/plugins/platforms/x11/standalone/x11_platform.h
--- a/plugins/platforms/x11/standalone/x11_platform.h
+++ b/plugins/platforms/x11/standalone/x11_platform.h
@@ -42,7 +42,7 @@
     Q_PLUGIN_METADATA(IID "org.kde.kwin.Platform" FILE "x11.json")
 public:
     X11StandalonePlatform(QObject *parent = nullptr);
-    virtual ~X11StandalonePlatform();
+    ~X11StandalonePlatform() override;
     void init() override;
 
     Screens *createScreens(QObject *parent = nullptr) override;
diff --git a/plugins/platforms/x11/standalone/x11cursor.h b/plugins/platforms/x11/standalone/x11cursor.h
--- a/plugins/platforms/x11/standalone/x11cursor.h
+++ b/plugins/platforms/x11/standalone/x11cursor.h
@@ -32,7 +32,7 @@
     Q_OBJECT
 public:
     X11Cursor(QObject *parent, bool xInputSupport = false);
-    virtual ~X11Cursor();
+    ~X11Cursor() override;
 
     void schedulePoll() {
         m_needsPoll = true;
@@ -46,14 +46,14 @@
     void notifyCursorChanged();
 
 protected:
-    virtual xcb_cursor_t getX11Cursor(CursorShape shape);
+    xcb_cursor_t getX11Cursor(CursorShape shape) override;
     xcb_cursor_t getX11Cursor(const QByteArray &name) override;
-    virtual void doSetPos();
-    virtual void doGetPos();
-    virtual void doStartMousePolling();
-    virtual void doStopMousePolling();
-    virtual void doStartCursorTracking();
-    virtual void doStopCursorTracking();
+    void doSetPos() override;
+    void doGetPos() override;
+    void doStartMousePolling() override;
+    void doStopMousePolling() override;
+    void doStartCursorTracking() override;
+    void doStopCursorTracking() override;
 
 private Q_SLOTS:
     /**
diff --git a/plugins/platforms/x11/standalone/xinputintegration.h b/plugins/platforms/x11/standalone/xinputintegration.h
--- a/plugins/platforms/x11/standalone/xinputintegration.h
+++ b/plugins/platforms/x11/standalone/xinputintegration.h
@@ -37,7 +37,7 @@
     Q_OBJECT
 public:
     explicit XInputIntegration(Display *display, QObject *parent);
-    virtual ~XInputIntegration();
+    ~XInputIntegration() override;
 
     void init();
     void startListening();
diff --git a/plugins/platforms/x11/standalone/xinputintegration.cpp b/plugins/platforms/x11/standalone/xinputintegration.cpp
--- a/plugins/platforms/x11/standalone/xinputintegration.cpp
+++ b/plugins/platforms/x11/standalone/xinputintegration.cpp
@@ -50,7 +50,7 @@
     XInputEventFilter(int xi_opcode)
         : X11EventFilter(XCB_GE_GENERIC, xi_opcode, QVector<int>{XI_RawMotion, XI_RawButtonPress, XI_RawButtonRelease, XI_RawKeyPress, XI_RawKeyRelease, XI_TouchBegin, XI_TouchUpdate, XI_TouchOwnership, XI_TouchEnd})
         {}
-    virtual ~XInputEventFilter() = default;
+    ~XInputEventFilter() override = default;
 
     bool event(xcb_generic_event_t *event) override {
         GeEventMemMover ge(event);
@@ -187,7 +187,7 @@
     XKeyPressReleaseEventFilter(uint32_t type)
         : X11EventFilter(type)
     {}
-    ~XKeyPressReleaseEventFilter() = default;
+    ~XKeyPressReleaseEventFilter() override = default;
 
     bool event(xcb_generic_event_t *event) override {
         xcb_key_press_event_t *ke = reinterpret_cast<xcb_key_press_event_t *>(event);
diff --git a/plugins/platforms/x11/windowed/egl_x11_backend.h b/plugins/platforms/x11/windowed/egl_x11_backend.h
--- a/plugins/platforms/x11/windowed/egl_x11_backend.h
+++ b/plugins/platforms/x11/windowed/egl_x11_backend.h
@@ -33,16 +33,16 @@
 {
 public:
     explicit EglX11Backend(X11WindowedBackend *backend);
-    virtual ~EglX11Backend();
-    virtual QRegion prepareRenderingFrame();
-    virtual void endRenderingFrame(const QRegion &damage, const QRegion &damagedRegion);
-    virtual bool usesOverlayWindow() const override;
+    ~EglX11Backend() override;
+    QRegion prepareRenderingFrame() override;
+    void endRenderingFrame(const QRegion &damage, const QRegion &damagedRegion) override;
+    bool usesOverlayWindow() const override;
     bool perScreenRendering() const override;
     QRegion prepareRenderingForScreen(int screenId) override;
     void endRenderingFrameForScreen(int screenId, const QRegion &damage, const QRegion &damagedRegion) override;
 
 protected:
-    virtual void present();
+    void present() override;
     void cleanupSurfaces() override;
     bool createSurfaces() override;
 
diff --git a/plugins/platforms/x11/windowed/scene_qpainter_x11_backend.h b/plugins/platforms/x11/windowed/scene_qpainter_x11_backend.h
--- a/plugins/platforms/x11/windowed/scene_qpainter_x11_backend.h
+++ b/plugins/platforms/x11/windowed/scene_qpainter_x11_backend.h
@@ -38,7 +38,7 @@
     Q_OBJECT
 public:
     X11WindowedQPainterBackend(X11WindowedBackend *backend);
-    virtual ~X11WindowedQPainterBackend();
+    ~X11WindowedQPainterBackend() override;
 
     QImage *buffer() override;
     QImage *bufferForScreen(int screenId) override;
diff --git a/plugins/platforms/x11/windowed/x11windowed_backend.h b/plugins/platforms/x11/windowed/x11windowed_backend.h
--- a/plugins/platforms/x11/windowed/x11windowed_backend.h
+++ b/plugins/platforms/x11/windowed/x11windowed_backend.h
@@ -45,7 +45,7 @@
     Q_PROPERTY(QSize size READ screenSize NOTIFY sizeChanged)
 public:
     X11WindowedBackend(QObject *parent = nullptr);
-    virtual ~X11WindowedBackend();
+    ~X11WindowedBackend() override;
     void init() override;
 
     xcb_connection_t *connection() const {
diff --git a/plugins/qpa/abstractplatformcontext.h b/plugins/qpa/abstractplatformcontext.h
--- a/plugins/qpa/abstractplatformcontext.h
+++ b/plugins/qpa/abstractplatformcontext.h
@@ -34,7 +34,7 @@
 {
 public:
     AbstractPlatformContext(QOpenGLContext *context, EGLDisplay display, EGLConfig config = nullptr);
-    virtual ~AbstractPlatformContext();
+    ~AbstractPlatformContext() override;
 
     void doneCurrent() override;
     QSurfaceFormat format() const override;
diff --git a/plugins/qpa/backingstore.h b/plugins/qpa/backingstore.h
--- a/plugins/qpa/backingstore.h
+++ b/plugins/qpa/backingstore.h
@@ -40,7 +40,7 @@
 {
 public:
     explicit BackingStore(QWindow *w, KWayland::Client::ShmPool *shm);
-    virtual ~BackingStore();
+    ~BackingStore() override;
 
     QPaintDevice *paintDevice() override;
     void flush(QWindow *window, const QRegion &region, const QPoint &offset) override;
diff --git a/plugins/qpa/integration.h b/plugins/qpa/integration.h
--- a/plugins/qpa/integration.h
+++ b/plugins/qpa/integration.h
@@ -48,7 +48,7 @@
     Q_OBJECT
 public:
     explicit Integration();
-    virtual ~Integration();
+    ~Integration() override;
 
     bool hasCapability(Capability cap) const override;
     QPlatformWindow *createPlatformWindow(QWindow *window) const override;
diff --git a/plugins/qpa/platformcursor.h b/plugins/qpa/platformcursor.h
--- a/plugins/qpa/platformcursor.h
+++ b/plugins/qpa/platformcursor.h
@@ -31,7 +31,7 @@
 {
 public:
     PlatformCursor();
-    virtual ~PlatformCursor();
+    ~PlatformCursor() override;
     QPoint pos() const override;
     void setPos(const QPoint &pos) override;
     void changeCursor(QCursor *windowCursor, QWindow *window) override;
diff --git a/plugins/qpa/screen.h b/plugins/qpa/screen.h
--- a/plugins/qpa/screen.h
+++ b/plugins/qpa/screen.h
@@ -33,7 +33,7 @@
 {
 public:
     explicit Screen(int screen);
-    virtual ~Screen();
+    ~Screen() override;
 
     QRect geometry() const override;
     int depth() const override;
diff --git a/plugins/qpa/window.h b/plugins/qpa/window.h
--- a/plugins/qpa/window.h
+++ b/plugins/qpa/window.h
@@ -52,7 +52,7 @@
 {
 public:
     explicit Window(QWindow *window, KWayland::Client::Surface *surface, KWayland::Client::ShellSurface *shellSurface, const Integration *integration);
-    virtual ~Window();
+    ~Window() override;
 
     void setVisible(bool visible) override;
     void setGeometry(const QRect &rect) override;
diff --git a/plugins/scenes/opengl/lanczosfilter.h b/plugins/scenes/opengl/lanczosfilter.h
--- a/plugins/scenes/opengl/lanczosfilter.h
+++ b/plugins/scenes/opengl/lanczosfilter.h
@@ -44,11 +44,11 @@
 
 public:
     explicit LanczosFilter(QObject* parent = 0);
-    ~LanczosFilter();
+    ~LanczosFilter() override;
     void performPaint(EffectWindowImpl* w, int mask, QRegion region, WindowPaintData& data);
 
 protected:
-    virtual void timerEvent(QTimerEvent*);
+    void timerEvent(QTimerEvent*) override;
 private:
     void init();
     void updateOffscreenSurfaces();
diff --git a/plugins/scenes/opengl/scene_opengl.h b/plugins/scenes/opengl/scene_opengl.h
--- a/plugins/scenes/opengl/scene_opengl.h
+++ b/plugins/scenes/opengl/scene_opengl.h
@@ -44,27 +44,27 @@
 public:
     class EffectFrame;
     class Window;
-    virtual ~SceneOpenGL();
-    virtual bool initFailed() const;
-    virtual bool hasPendingFlush() const;
-    virtual qint64 paint(QRegion damage, ToplevelList windows);
-    virtual Scene::EffectFrame *createEffectFrame(EffectFrameImpl *frame);
-    virtual Shadow *createShadow(Toplevel *toplevel);
-    virtual void screenGeometryChanged(const QSize &size);
-    virtual OverlayWindow *overlayWindow();
-    virtual bool usesOverlayWindow() const;
-    virtual bool blocksForRetrace() const;
-    virtual bool syncsToVBlank() const;
-    virtual bool makeOpenGLContextCurrent() override;
-    virtual void doneOpenGLContextCurrent() override;
+    ~SceneOpenGL() override;
+    bool initFailed() const override;
+    bool hasPendingFlush() const override;
+    qint64 paint(QRegion damage, ToplevelList windows) override;
+    Scene::EffectFrame *createEffectFrame(EffectFrameImpl *frame) override;
+    Shadow *createShadow(Toplevel *toplevel) override;
+    void screenGeometryChanged(const QSize &size) override;
+    OverlayWindow *overlayWindow() override;
+    bool usesOverlayWindow() const override;
+    bool blocksForRetrace() const override;
+    bool syncsToVBlank() const override;
+    bool makeOpenGLContextCurrent() override;
+    void doneOpenGLContextCurrent() override;
     Decoration::Renderer *createDecorationRenderer(Decoration::DecoratedClientImpl *impl) override;
-    virtual void triggerFence() override;
+    void triggerFence() override;
     virtual QMatrix4x4 projectionMatrix() const = 0;
     bool animationsSupported() const override;
 
     void insertWait();
 
-    void idle();
+    void idle() override;
 
     bool debug() const { return m_debug; }
     void initDebugOutput();
@@ -86,10 +86,10 @@
 
 protected:
     SceneOpenGL(OpenGLBackend *backend, QObject *parent = nullptr);
-    virtual void paintBackground(QRegion region);
-    virtual void extendPaintRegion(QRegion &region, bool opaqueFullscreen);
+    void paintBackground(QRegion region) override;
+    void extendPaintRegion(QRegion &region, bool opaqueFullscreen) override;
     QMatrix4x4 transformation(int mask, const ScreenPaintData &data) const;
-    virtual void paintDesktop(int desktop, int mask, const QRegion &region, ScreenPaintData &data);
+    void paintDesktop(int desktop, int mask, const QRegion &region, ScreenPaintData &data) override;
 
     void handleGraphicsReset(GLenum status);
 
@@ -112,8 +112,8 @@
     Q_OBJECT
 public:
     explicit SceneOpenGL2(OpenGLBackend *backend, QObject *parent = nullptr);
-    virtual ~SceneOpenGL2();
-    virtual CompositingType compositingType() const {
+    ~SceneOpenGL2() override;
+    CompositingType compositingType() const override {
         return OpenGL2Compositing;
     }
 
@@ -123,12 +123,12 @@
     QMatrix4x4 screenProjectionMatrix() const override { return m_screenProjectionMatrix; }
 
 protected:
-    virtual void paintSimpleScreen(int mask, QRegion region);
-    virtual void paintGenericScreen(int mask, ScreenPaintData data);
-    virtual void doPaintBackground(const QVector< float >& vertices);
-    virtual Scene::Window *createWindow(Toplevel *t);
-    virtual void finalDrawWindow(EffectWindowImpl* w, int mask, QRegion region, WindowPaintData& data);
-    virtual void updateProjectionMatrix() override;
+    void paintSimpleScreen(int mask, QRegion region) override;
+    void paintGenericScreen(int mask, ScreenPaintData data) override;
+    void doPaintBackground(const QVector< float >& vertices) override;
+    Scene::Window *createWindow(Toplevel *t) override;
+    void finalDrawWindow(EffectWindowImpl* w, int mask, QRegion region, WindowPaintData& data) override;
+    void updateProjectionMatrix() override;
     void paintCursor() override;
 
 private:
@@ -147,17 +147,17 @@
     : public Scene::Window
 {
 public:
-    virtual ~Window();
+    ~Window() override;
     bool beginRenderWindow(int mask, const QRegion &region, WindowPaintData &data);
-    virtual void performPaint(int mask, QRegion region, WindowPaintData data) = 0;
+    void performPaint(int mask, QRegion region, WindowPaintData data) override = 0;
     void endRenderWindow();
     bool bindTexture();
     void setScene(SceneOpenGL *scene) {
         m_scene = scene;
     }
 
 protected:
-    virtual WindowPixmap* createWindowPixmap();
+    WindowPixmap* createWindowPixmap() override;
     Window(Toplevel* c);
     enum TextureType {
         Content,
@@ -201,14 +201,14 @@
     };
 
     explicit SceneOpenGL2Window(Toplevel *c);
-    virtual ~SceneOpenGL2Window();
+    ~SceneOpenGL2Window() override;
 
 protected:
     QMatrix4x4 modelViewProjectionMatrix(int mask, const WindowPaintData &data) const;
     QVector4D modulate(float opacity, float brightness) const;
     void setBlendEnabled(bool enabled);
     void setupLeafNodes(LeafNode *nodes, const WindowQuadList *quads, const WindowPaintData &data);
-    virtual void performPaint(int mask, QRegion region, WindowPaintData data);
+    void performPaint(int mask, QRegion region, WindowPaintData data) override;
 
 private:
     void renderSubSurface(GLShader *shader, const QMatrix4x4 &mvp, const QMatrix4x4 &windowMatrix, OpenGLWindowPixmap *pixmap, const QRegion &region, bool hardwareClipping);
@@ -222,7 +222,7 @@
 {
 public:
     explicit OpenGLWindowPixmap(Scene::Window *window, SceneOpenGL *scene);
-    virtual ~OpenGLWindowPixmap();
+    ~OpenGLWindowPixmap() override;
     SceneOpenGLTexture *texture() const;
     bool bind();
     bool isValid() const override;
@@ -239,17 +239,17 @@
 {
 public:
     EffectFrame(EffectFrameImpl* frame, SceneOpenGL *scene);
-    virtual ~EffectFrame();
+    ~EffectFrame() override;
 
-    virtual void free();
-    virtual void freeIconFrame();
-    virtual void freeTextFrame();
-    virtual void freeSelection();
+    void free() override;
+    void freeIconFrame() override;
+    void freeTextFrame() override;
+    void freeSelection() override;
 
-    virtual void render(QRegion region, double opacity, double frameOpacity);
+    void render(QRegion region, double opacity, double frameOpacity) override;
 
-    virtual void crossFadeIcon();
-    virtual void crossFadeText();
+    void crossFadeIcon() override;
+    void crossFadeText() override;
 
     static void cleanup();
 
@@ -283,14 +283,14 @@
 {
 public:
     explicit SceneOpenGLShadow(Toplevel *toplevel);
-    virtual ~SceneOpenGLShadow();
+    ~SceneOpenGLShadow() override;
 
     GLTexture *shadowTexture() {
         return m_texture.data();
     }
 protected:
-    virtual void buildQuads();
-    virtual bool prepareBackend();
+    void buildQuads() override;
+    bool prepareBackend() override;
 private:
     QSharedPointer<GLTexture> m_texture;
 };
@@ -307,7 +307,7 @@
         Count
     };
     explicit SceneOpenGLDecorationRenderer(Decoration::DecoratedClientImpl *client);
-    virtual ~SceneOpenGLDecorationRenderer();
+    ~SceneOpenGLDecorationRenderer() override;
 
     void render() override;
     void reparent(Deleted *deleted) override;
diff --git a/plugins/scenes/qpainter/scene_qpainter.h b/plugins/scenes/qpainter/scene_qpainter.h
--- a/plugins/scenes/qpainter/scene_qpainter.h
+++ b/plugins/scenes/qpainter/scene_qpainter.h
@@ -33,15 +33,15 @@
     Q_OBJECT
 
 public:
-    virtual ~SceneQPainter();
-    virtual bool usesOverlayWindow() const override;
-    virtual OverlayWindow* overlayWindow() override;
-    virtual qint64 paint(QRegion damage, ToplevelList windows) override;
-    virtual void paintGenericScreen(int mask, ScreenPaintData data) override;
-    virtual CompositingType compositingType() const override;
-    virtual bool initFailed() const override;
-    virtual EffectFrame *createEffectFrame(EffectFrameImpl *frame) override;
-    virtual Shadow *createShadow(Toplevel *toplevel) override;
+    ~SceneQPainter() override;
+    bool usesOverlayWindow() const override;
+    OverlayWindow* overlayWindow() override;
+    qint64 paint(QRegion damage, ToplevelList windows) override;
+    void paintGenericScreen(int mask, ScreenPaintData data) override;
+    CompositingType compositingType() const override;
+    bool initFailed() const override;
+    EffectFrame *createEffectFrame(EffectFrameImpl *frame) override;
+    Shadow *createShadow(Toplevel *toplevel) override;
     Decoration::Renderer *createDecorationRenderer(Decoration::DecoratedClientImpl *impl) override;
     void screenGeometryChanged(const QSize &size) override;
 
@@ -59,8 +59,8 @@
     static SceneQPainter *createScene(QObject *parent);
 
 protected:
-    virtual void paintBackground(QRegion region) override;
-    virtual Scene::Window *createWindow(Toplevel *toplevel) override;
+    void paintBackground(QRegion region) override;
+    Scene::Window *createWindow(Toplevel *toplevel) override;
     void paintCursor() override;
 
 private:
@@ -74,10 +74,10 @@
 {
 public:
     Window(SceneQPainter *scene, Toplevel *c);
-    virtual ~Window();
-    virtual void performPaint(int mask, QRegion region, WindowPaintData data) override;
+    ~Window() override;
+    void performPaint(int mask, QRegion region, WindowPaintData data) override;
 protected:
-    virtual WindowPixmap *createWindowPixmap() override;
+    WindowPixmap *createWindowPixmap() override;
 private:
     void renderShadow(QPainter *painter);
     void renderWindowDecorations(QPainter *painter);
@@ -88,8 +88,8 @@
 {
 public:
     explicit QPainterWindowPixmap(Scene::Window *window);
-    virtual ~QPainterWindowPixmap();
-    virtual void create() override;
+    ~QPainterWindowPixmap() override;
+    void create() override;
     bool isValid() const override;
 
     void updateBuffer() override;
@@ -106,31 +106,31 @@
 {
 public:
     QPainterEffectFrame(EffectFrameImpl *frame, SceneQPainter *scene);
-    virtual ~QPainterEffectFrame();
-    virtual void crossFadeIcon() override {}
-    virtual void crossFadeText() override {}
-    virtual void free() override {}
-    virtual void freeIconFrame() override {}
-    virtual void freeTextFrame() override {}
-    virtual void freeSelection() override {}
-    virtual void render(QRegion region, double opacity, double frameOpacity) override;
+    ~QPainterEffectFrame() override;
+    void crossFadeIcon() override {}
+    void crossFadeText() override {}
+    void free() override {}
+    void freeIconFrame() override {}
+    void freeTextFrame() override {}
+    void freeSelection() override {}
+    void render(QRegion region, double opacity, double frameOpacity) override;
 private:
     SceneQPainter *m_scene;
 };
 
 class SceneQPainterShadow : public Shadow
 {
 public:
     SceneQPainterShadow(Toplevel* toplevel);
-    virtual ~SceneQPainterShadow();
+    ~SceneQPainterShadow() override;
 
     QImage &shadowTexture() {
         return m_texture;
     }
 
 protected:
-    virtual void buildQuads() override;
-    virtual bool prepareBackend() override;
+    void buildQuads() override;
+    bool prepareBackend() override;
 
 private:
     QImage m_texture;
@@ -148,7 +148,7 @@
         Count
     };
     explicit SceneQPainterDecorationRenderer(Decoration::DecoratedClientImpl *client);
-    virtual ~SceneQPainterDecorationRenderer();
+    ~SceneQPainterDecorationRenderer() override;
 
     void render() override;
     void reparent(Deleted *deleted) override;
diff --git a/plugins/scenes/xrender/scene_xrender.h b/plugins/scenes/xrender/scene_xrender.h
--- a/plugins/scenes/xrender/scene_xrender.h
+++ b/plugins/scenes/xrender/scene_xrender.h
@@ -128,13 +128,13 @@
 {
 public:
     X11XRenderBackend();
-    ~X11XRenderBackend();
+    ~X11XRenderBackend() override;
 
-    virtual void present(int mask, const QRegion &damage);
-    virtual OverlayWindow* overlayWindow();
-    virtual void showOverlay();
-    virtual void screenGeometryChanged(const QSize &size);
-    virtual bool usesOverlayWindow() const;
+    void present(int mask, const QRegion &damage) override;
+    OverlayWindow* overlayWindow() override;
+    void showOverlay() override;
+    void screenGeometryChanged(const QSize &size) override;
+    bool usesOverlayWindow() const override;
 private:
     void init(bool createOverlay);
     void createBuffer();
@@ -149,34 +149,34 @@
     Q_OBJECT
 public:
     class EffectFrame;
-    virtual ~SceneXrender();
-    virtual bool initFailed() const;
-    virtual CompositingType compositingType() const {
+    ~SceneXrender() override;
+    bool initFailed() const override;
+    CompositingType compositingType() const override {
         return XRenderCompositing;
     }
-    virtual qint64 paint(QRegion damage, ToplevelList windows);
-    virtual Scene::EffectFrame *createEffectFrame(EffectFrameImpl *frame);
-    virtual Shadow *createShadow(Toplevel *toplevel);
-    virtual void screenGeometryChanged(const QSize &size);
+    qint64 paint(QRegion damage, ToplevelList windows) override;
+    Scene::EffectFrame *createEffectFrame(EffectFrameImpl *frame) override;
+    Shadow *createShadow(Toplevel *toplevel) override;
+    void screenGeometryChanged(const QSize &size) override;
     xcb_render_picture_t xrenderBufferPicture() const override;
-    virtual OverlayWindow *overlayWindow() {
+    OverlayWindow *overlayWindow() override {
         return m_backend->overlayWindow();
     }
-    virtual bool usesOverlayWindow() const {
+    bool usesOverlayWindow() const override {
         return m_backend->usesOverlayWindow();
     }
-    Decoration::Renderer *createDecorationRenderer(Decoration::DecoratedClientImpl *client);
+    Decoration::Renderer *createDecorationRenderer(Decoration::DecoratedClientImpl *client) override;
 
     bool animationsSupported() const override {
         return true;
     }
 
     static SceneXrender *createScene(QObject *parent);
 protected:
-    virtual Scene::Window *createWindow(Toplevel *toplevel);
-    virtual void paintBackground(QRegion region);
-    virtual void paintGenericScreen(int mask, ScreenPaintData data);
-    virtual void paintDesktop(int desktop, int mask, const QRegion &region, ScreenPaintData &data);
+    Scene::Window *createWindow(Toplevel *toplevel) override;
+    void paintBackground(QRegion region) override;
+    void paintGenericScreen(int mask, ScreenPaintData data) override;
+    void paintDesktop(int desktop, int mask, const QRegion &region, ScreenPaintData &data) override;
     void paintCursor() override;
 private:
     explicit SceneXrender(XRenderBackend *backend, QObject *parent = nullptr);
@@ -190,13 +190,13 @@
 {
 public:
     Window(Toplevel* c, SceneXrender *scene);
-    virtual ~Window();
-    virtual void performPaint(int mask, QRegion region, WindowPaintData data);
+    ~Window() override;
+    void performPaint(int mask, QRegion region, WindowPaintData data) override;
     QRegion transformedShape() const;
     void setTransformedShape(const QRegion& shape);
     static void cleanup();
 protected:
-    virtual WindowPixmap* createWindowPixmap();
+    WindowPixmap* createWindowPixmap() override;
 private:
     QRect mapToScreen(int mask, const WindowPaintData &data, const QRect &rect) const;
     QPoint mapToScreen(int mask, const WindowPaintData &data, const QPoint &point) const;
@@ -214,9 +214,9 @@
 {
 public:
     explicit XRenderWindowPixmap(Scene::Window *window, xcb_render_pictformat_t format);
-    virtual ~XRenderWindowPixmap();
+    ~XRenderWindowPixmap() override;
     xcb_render_picture_t picture() const;
-    virtual void create();
+    void create() override;
 private:
     xcb_render_picture_t m_picture;
     xcb_render_pictformat_t m_format;
@@ -227,15 +227,15 @@
 {
 public:
     EffectFrame(EffectFrameImpl* frame);
-    virtual ~EffectFrame();
-
-    virtual void free();
-    virtual void freeIconFrame();
-    virtual void freeTextFrame();
-    virtual void freeSelection();
-    virtual void crossFadeIcon();
-    virtual void crossFadeText();
-    virtual void render(QRegion region, double opacity, double frameOpacity);
+    ~EffectFrame() override;
+
+    void free() override;
+    void freeIconFrame() override;
+    void freeTextFrame() override;
+    void freeSelection() override;
+    void crossFadeIcon() override;
+    void crossFadeText() override;
+    void render(QRegion region, double opacity, double frameOpacity) override;
     static void cleanup();
 
 private:
@@ -296,17 +296,17 @@
     using Shadow::ShadowElementTopLeft;
     using Shadow::ShadowElementsCount;
     using Shadow::shadowPixmap;
-    virtual ~SceneXRenderShadow();
+    ~SceneXRenderShadow() override;
 
     void layoutShadowRects(QRect& top, QRect& topRight,
                            QRect& right, QRect& bottomRight,
                            QRect& bottom, QRect& bottomLeft,
                            QRect& Left, QRect& topLeft);
     xcb_render_picture_t picture(ShadowElements element) const;
 
 protected:
-    virtual void buildQuads();
-    virtual bool prepareBackend();
+    void buildQuads() override;
+    bool prepareBackend() override;
 private:
     XRenderPicture* m_pictures[ShadowElementsCount];
 };
@@ -323,7 +323,7 @@
         Count
     };
     explicit SceneXRenderDecorationRenderer(Decoration::DecoratedClientImpl *client);
-    virtual ~SceneXRenderDecorationRenderer();
+    ~SceneXRenderDecorationRenderer() override;
 
     void render() override;
     void reparent(Deleted *deleted) override;
diff --git a/pointer_input.h b/pointer_input.h
--- a/pointer_input.h
+++ b/pointer_input.h
@@ -62,9 +62,9 @@
     Q_OBJECT
 public:
     explicit PointerInputRedirection(InputRedirection *parent);
-    virtual ~PointerInputRedirection();
+    ~PointerInputRedirection() override;
 
-    void init();
+    void init() override;
 
     void updateAfterScreenChange();
     bool supportsWarping() const;
@@ -185,7 +185,7 @@
     Q_OBJECT
 public:
     explicit CursorImage(PointerInputRedirection *parent = nullptr);
-    virtual ~CursorImage();
+    ~CursorImage() override;
 
     void setEffectsOverrideCursor(Qt::CursorShape shape);
     void removeEffectsOverrideCursor();
diff --git a/rules.h b/rules.h
--- a/rules.h
+++ b/rules.h
@@ -295,7 +295,7 @@
 {
     Q_OBJECT
 public:
-    virtual ~RuleBook();
+    ~RuleBook() override;
     WindowRules find(const AbstractClient*, bool);
     void discardUsed(AbstractClient* c, bool withdraw);
     void setUpdatesDisabled(bool disable);
diff --git a/scene.h b/scene.h
--- a/scene.h
+++ b/scene.h
@@ -62,7 +62,7 @@
     Q_OBJECT
 public:
     explicit Scene(QObject *parent = nullptr);
-    virtual ~Scene() = 0;
+    ~Scene() override = 0;
     class EffectFrame;
     class Window;
 
@@ -274,7 +274,7 @@
 {
     Q_OBJECT
 public:
-    virtual ~SceneFactory();
+    ~SceneFactory() override;
 
     /**
      * @returns The created Scene, may be @c nullptr.
diff --git a/screenedge.h b/screenedge.h
--- a/screenedge.h
+++ b/screenedge.h
@@ -54,7 +54,7 @@
     Q_OBJECT
 public:
     explicit Edge(ScreenEdges *parent);
-    virtual ~Edge();
+    ~Edge() override;
     bool isLeft() const;
     bool isTop() const;
     bool isRight() const;
@@ -216,7 +216,7 @@
     Q_PROPERTY(int actionBottomLeft READ actionBottomLeft)
     Q_PROPERTY(int actionLeft READ actionLeft)
 public:
-    virtual ~ScreenEdges();
+    ~ScreenEdges() override;
     /**
      * @internal
      **/
diff --git a/screenlockerwatcher.h b/screenlockerwatcher.h
--- a/screenlockerwatcher.h
+++ b/screenlockerwatcher.h
@@ -36,7 +36,7 @@
 {
     Q_OBJECT
 public:
-    virtual ~ScreenLockerWatcher();
+    ~ScreenLockerWatcher() override;
     bool isLocked() const {
         return m_locked;
     }
diff --git a/screens.h b/screens.h
--- a/screens.h
+++ b/screens.h
@@ -45,7 +45,7 @@
     Q_PROPERTY(bool currentFollowsMouse READ isCurrentFollowsMouse WRITE setCurrentFollowsMouse)
 
 public:
-    virtual ~Screens();
+    ~Screens() override;
     /**
      * @internal
      **/
diff --git a/scripting/dbuscall.h b/scripting/dbuscall.h
--- a/scripting/dbuscall.h
+++ b/scripting/dbuscall.h
@@ -82,7 +82,7 @@
     Q_PROPERTY(QVariantList arguments READ arguments WRITE setArguments NOTIFY argumentsChanged)
 public:
     explicit DBusCall(QObject* parent = 0);
-    virtual ~DBusCall();
+    ~DBusCall() override;
 
     const QString &service() const;
     const QString &path() const;
diff --git a/scripting/genericscriptedconfig.h b/scripting/genericscriptedconfig.h
--- a/scripting/genericscriptedconfig.h
+++ b/scripting/genericscriptedconfig.h
@@ -46,10 +46,10 @@
 
 public:
     GenericScriptedConfig(const QString &componentName, const QString &keyword, QWidget *parent, const QVariantList &args);
-    virtual ~GenericScriptedConfig();
+    ~GenericScriptedConfig() override;
 
 public Q_SLOTS:
-    virtual void save();
+    void save() override;
 
 protected:
     const QString &packageName() const;
@@ -68,24 +68,24 @@
     Q_OBJECT
 public:
     ScriptedEffectConfig(const QString &componentName, const QString &keyword, QWidget *parent, const QVariantList &args);
-    virtual ~ScriptedEffectConfig();
+    ~ScriptedEffectConfig() override;
 protected:
-    virtual QString typeName() const;
-    virtual KConfigGroup configGroup();
-    virtual void reload();
+    QString typeName() const override;
+    KConfigGroup configGroup() override;
+    void reload() override;
 };
 
 class ScriptingConfig : public GenericScriptedConfig
 {
     Q_OBJECT
 public:
     ScriptingConfig(const QString &componentName, const QString &keyword, QWidget *parent, const QVariantList &args);
-    virtual ~ScriptingConfig();
+    ~ScriptingConfig() override;
 
 protected:
-    virtual QString typeName() const;
-    virtual KConfigGroup configGroup();
-    virtual void reload();
+    QString typeName() const override;
+    KConfigGroup configGroup() override;
+    void reload() override;
 };
 
 inline
diff --git a/scripting/screenedgeitem.h b/scripting/screenedgeitem.h
--- a/scripting/screenedgeitem.h
+++ b/scripting/screenedgeitem.h
@@ -81,7 +81,7 @@
         Touch
     };
     explicit ScreenEdgeItem(QObject *parent = 0);
-    virtual ~ScreenEdgeItem();
+    ~ScreenEdgeItem() override;
     bool isEnabled() const;
     Edge edge() const;
     Mode mode() const {
diff --git a/scripting/scriptedeffect.h b/scripting/scriptedeffect.h
--- a/scripting/scriptedeffect.h
+++ b/scripting/scriptedeffect.h
@@ -63,16 +63,16 @@
     const QString &scriptFile() const {
         return m_scriptFile;
     }
-    virtual void reconfigure(ReconfigureFlags flags);
+    void reconfigure(ReconfigureFlags flags) override;
     int requestedEffectChainPosition() const override {
         return m_chainPosition;
     }
     QString activeConfig() const;
     void setActiveConfig(const QString &name);
     static ScriptedEffect *create(const QString &effectName, const QString &pathToScript, int chainPosition);
     static ScriptedEffect *create(const KPluginMetaData &effect);
     static bool supported();
-    virtual ~ScriptedEffect();
+    ~ScriptedEffect() override;
     /**
      * Whether another effect has grabbed the @p w with the given @p grabRole.
      * @param w The window to check
@@ -131,7 +131,7 @@
     bool redirect(quint64 animationId, Direction direction, TerminationFlags terminationFlags = TerminateAtSource);
     bool complete(quint64 animationId);
     bool cancel(quint64 animationId) { return AnimationEffect::cancel(animationId); }
-    virtual bool borderActivated(ElectricBorder border);
+    bool borderActivated(ElectricBorder border) override;
 
 Q_SIGNALS:
     /**
@@ -145,7 +145,7 @@
     ScriptedEffect();
     QScriptEngine *engine() const;
     bool init(const QString &effectName, const QString &pathToScript);
-    void animationEnded(KWin::EffectWindow *w, Attribute a, uint meta);
+    void animationEnded(KWin::EffectWindow *w, Attribute a, uint meta) override;
 
 private Q_SLOTS:
     void signalHandlerException(const QScriptValue &value);
diff --git a/scripting/scripting.h b/scripting/scripting.h
--- a/scripting/scripting.h
+++ b/scripting/scripting.h
@@ -61,7 +61,7 @@
     Q_OBJECT
 public:
     AbstractScript(int id, QString scriptName, QString pluginName, QObject *parent = nullptr);
-    ~AbstractScript();
+    ~AbstractScript() override;
     QString fileName() const {
         return m_fileName;
     }
@@ -224,16 +224,16 @@
 public:
 
     Script(int id, QString scriptName, QString pluginName, QObject *parent = nullptr);
-    virtual ~Script();
+    ~Script() override;
     QScriptEngine *engine() {
         return m_engine;
     }
 
     bool registerTouchScreenCallback(int edge, QScriptValue callback);
     bool unregisterTouchScreenCallback(int edge);
 
 public Q_SLOTS:
-    Q_SCRIPTABLE void run();
+    Q_SCRIPTABLE void run() override;
 
 Q_SIGNALS:
     Q_SCRIPTABLE void printError(const QString &text);
@@ -267,7 +267,7 @@
 {
 public:
     explicit ScriptUnloaderAgent(Script *script);
-    virtual void scriptUnload(qint64 id);
+    void scriptUnload(qint64 id) override;
 
 private:
     Script *m_script;
@@ -279,10 +279,10 @@
     Q_CLASSINFO("D-Bus Interface", "org.kde.kwin.Scripting")
 public:
     explicit DeclarativeScript(int id, QString scriptName, QString pluginName, QObject *parent = nullptr);
-    virtual ~DeclarativeScript();
+    ~DeclarativeScript() override;
 
 public Q_SLOTS:
-    Q_SCRIPTABLE void run();
+    Q_SCRIPTABLE void run() override;
 
 private Q_SLOTS:
     void createComponent();
@@ -319,7 +319,7 @@
         ScreenArea
     };
     explicit JSEngineGlobalMethodsWrapper(DeclarativeScript *parent);
-    virtual ~JSEngineGlobalMethodsWrapper();
+    ~JSEngineGlobalMethodsWrapper() override;
 
 public Q_SLOTS:
     QVariant readConfig(const QString &key, QVariant defaultValue = QVariant());
@@ -350,7 +350,7 @@
     void runScripts();
 
 public:
-    ~Scripting();
+    ~Scripting() override;
     Q_SCRIPTABLE Q_INVOKABLE int loadScript(const QString &filePath, const QString &pluginName = QString());
     Q_SCRIPTABLE Q_INVOKABLE int loadDeclarativeScript(const QString &filePath, const QString &pluginName = QString());
     Q_SCRIPTABLE Q_INVOKABLE bool isScriptLoaded(const QString &pluginName) const;
diff --git a/scripting/scripting_model.h b/scripting/scripting_model.h
--- a/scripting/scripting_model.h
+++ b/scripting/scripting_model.h
@@ -68,13 +68,13 @@
     Q_DECLARE_FLAGS(LevelRestrictions, LevelRestriction)
     Q_FLAGS(LevelRestrictions)
     explicit ClientModel(QObject *parent);
-    virtual ~ClientModel();
-    virtual int columnCount(const QModelIndex &parent = QModelIndex()) const;
-    virtual QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const;
-    virtual QModelIndex index(int row, int column, const QModelIndex &parent = QModelIndex()) const;
-    virtual QModelIndex parent(const QModelIndex &child) const;
-    virtual int rowCount(const QModelIndex &parent = QModelIndex()) const;
-    virtual QHash<int, QByteArray> roleNames() const;
+    ~ClientModel() override;
+    int columnCount(const QModelIndex &parent = QModelIndex()) const override;
+    QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const override;
+    QModelIndex index(int row, int column, const QModelIndex &parent = QModelIndex()) const override;
+    QModelIndex parent(const QModelIndex &child) const override;
+    int rowCount(const QModelIndex &parent = QModelIndex()) const override;
+    QHash<int, QByteArray> roleNames() const override;
 
     void setExclusions(ClientModel::Exclusions exclusions);
     Exclusions exclusions() const;
@@ -130,7 +130,7 @@
 {
     Q_OBJECT
 public:
-    virtual ~AbstractLevel();
+    ~AbstractLevel() override;
     virtual int count() const = 0;
     virtual void init() = 0;
     virtual quint32 idForRow(int row) const = 0;
@@ -179,18 +179,18 @@
     Q_OBJECT
 public:
     ForkLevel(const QList<ClientModel::LevelRestriction> &childRestrictions, ClientModel *model, AbstractLevel *parent);
-    virtual ~ForkLevel();
-    virtual int count() const;
-    virtual void init();
-    virtual quint32 idForRow(int row) const;
+    ~ForkLevel() override;
+    int count() const override;
+    void init() override;
+    quint32 idForRow(int row) const override;
     void addChild(AbstractLevel *child);
-    virtual void setScreen(uint screen);
-    virtual void setVirtualDesktop(uint virtualDesktop);
-    virtual void setActivity(const QString &activity);
-    virtual const AbstractLevel *levelForId(quint32 id) const;
-    virtual AbstractLevel *parentForId(quint32 child) const;
-    virtual int rowForId(quint32 child) const;
-    virtual AbstractClient *clientForId(quint32 child) const override;
+    void setScreen(uint screen) override;
+    void setVirtualDesktop(uint virtualDesktop) override;
+    void setActivity(const QString &activity) override;
+    const AbstractLevel *levelForId(quint32 id) const override;
+    AbstractLevel *parentForId(quint32 child) const override;
+    int rowForId(quint32 child) const override;
+    AbstractClient *clientForId(quint32 child) const override;
 private Q_SLOTS:
     void desktopCountChanged(uint previousCount, uint newCount);
     void screenCountChanged(int previousCount, int newCount);
@@ -216,17 +216,17 @@
     Q_OBJECT
 public:
     explicit ClientLevel(ClientModel *model, AbstractLevel *parent);
-    virtual ~ClientLevel();
+    ~ClientLevel() override;
 
-    void init();
+    void init() override;
 
-    int count() const;
-    quint32 idForRow(int row) const;
+    int count() const override;
+    quint32 idForRow(int row) const override;
     bool containsId(quint32 id) const;
-    int rowForId(quint32 row) const;
-    AbstractClient *clientForId(quint32 child) const;
-    virtual const AbstractLevel *levelForId(quint32 id) const;
-    virtual AbstractLevel *parentForId(quint32 child) const override;
+    int rowForId(quint32 row) const override;
+    AbstractClient *clientForId(quint32 child) const override;
+    const AbstractLevel *levelForId(quint32 id) const override;
+    AbstractLevel *parentForId(quint32 child) const override;
 public Q_SLOTS:
     void clientAdded(KWin::AbstractClient *client);
     void clientRemoved(KWin::AbstractClient *client);
@@ -249,23 +249,23 @@
     Q_OBJECT
 public:
     SimpleClientModel(QObject *parent = nullptr);
-    virtual ~SimpleClientModel();
+    ~SimpleClientModel() override;
 };
 
 class ClientModelByScreen : public ClientModel
 {
     Q_OBJECT
 public:
     ClientModelByScreen(QObject *parent = nullptr);
-    virtual ~ClientModelByScreen();
+    ~ClientModelByScreen() override;
 };
 
 class ClientModelByScreenAndDesktop : public ClientModel
 {
     Q_OBJECT
 public:
     ClientModelByScreenAndDesktop(QObject *parent = nullptr);
-    virtual ~ClientModelByScreenAndDesktop();
+    ~ClientModelByScreenAndDesktop() override;
 };
 
 /**
@@ -278,16 +278,16 @@
     Q_PROPERTY(QString filter READ filter WRITE setFilter NOTIFY filterChanged)
 public:
     ClientFilterModel(QObject *parent = nullptr);
-    virtual ~ClientFilterModel();
+    ~ClientFilterModel() override;
     ClientModel *clientModel() const;
     const QString &filter() const;
 
 public Q_SLOTS:
     void setClientModel(ClientModel *clientModel);
     void setFilter(const QString &filter);
 
 protected:
-    virtual bool filterAcceptsRow(int source_row, const QModelIndex &source_parent) const;
+    bool filterAcceptsRow(int source_row, const QModelIndex &source_parent) const override;
 
 Q_SIGNALS:
     void clientModelChanged();
diff --git a/shadow.h b/shadow.h
--- a/shadow.h
+++ b/shadow.h
@@ -61,7 +61,7 @@
 {
     Q_OBJECT
 public:
-    virtual ~Shadow();
+    ~Shadow() override;
 
     /**
      * @return Region of the shadow.
diff --git a/shell_client.h b/shell_client.h
--- a/shell_client.h
+++ b/shell_client.h
@@ -55,7 +55,7 @@
     ShellClient(KWayland::Server::ShellSurfaceInterface *surface);
     ShellClient(KWayland::Server::XdgShellSurfaceInterface *surface);
     ShellClient(KWayland::Server::XdgShellPopupInterface *surface);
-    virtual ~ShellClient();
+    ~ShellClient() override;
 
     QStringList activities() const override;
     QPoint clientContentPos() const override;
diff --git a/sm.h b/sm.h
--- a/sm.h
+++ b/sm.h
@@ -85,7 +85,7 @@
     Q_OBJECT
 public:
     SessionSaveDoneHelper();
-    virtual ~SessionSaveDoneHelper();
+    ~SessionSaveDoneHelper() override;
     SmcConn connection() const {
         return conn;
     }
diff --git a/tabbox/clientmodel.h b/tabbox/clientmodel.h
--- a/tabbox/clientmodel.h
+++ b/tabbox/clientmodel.h
@@ -58,13 +58,13 @@
         CloseableRole = Qt::UserRole + 7 ///< TabBoxClient can be closed
     };
     explicit ClientModel(QObject* parent = nullptr);
-    ~ClientModel();
-    virtual QVariant data(const QModelIndex& index, int role = Qt::DisplayRole) const;
-    virtual int columnCount(const QModelIndex& parent = QModelIndex()) const;
-    virtual int rowCount(const QModelIndex& parent = QModelIndex()) const;
-    virtual QModelIndex parent(const QModelIndex& child) const;
-    virtual QModelIndex index(int row, int column, const QModelIndex& parent = QModelIndex()) const;
-    virtual QHash<int, QByteArray> roleNames() const;
+    ~ClientModel() override;
+    QVariant data(const QModelIndex& index, int role = Qt::DisplayRole) const override;
+    int columnCount(const QModelIndex& parent = QModelIndex()) const override;
+    int rowCount(const QModelIndex& parent = QModelIndex()) const override;
+    QModelIndex parent(const QModelIndex& child) const override;
+    QModelIndex index(int row, int column, const QModelIndex& parent = QModelIndex()) const override;
+    QHash<int, QByteArray> roleNames() const override;
     Q_INVOKABLE QString longestCaption() const;
 
     /**
diff --git a/tabbox/desktopchain.h b/tabbox/desktopchain.h
--- a/tabbox/desktopchain.h
+++ b/tabbox/desktopchain.h
@@ -89,7 +89,7 @@
 
 public:
     explicit DesktopChainManager(QObject *parent = nullptr);
-    virtual ~DesktopChainManager();
+    ~DesktopChainManager() override;
 
     /**
      * Returns the next virtual desktop starting from @p indexDesktop in the currently used chain.
diff --git a/tabbox/desktopmodel.h b/tabbox/desktopmodel.h
--- a/tabbox/desktopmodel.h
+++ b/tabbox/desktopmodel.h
@@ -52,14 +52,14 @@
         ClientModelRole = Qt::UserRole + 2 ///< Clients on this desktop
     };
     explicit DesktopModel(QObject* parent = nullptr);
-    ~DesktopModel();
+    ~DesktopModel() override;
 
-    virtual QVariant data(const QModelIndex& index, int role = Qt::DisplayRole) const;
-    virtual int columnCount(const QModelIndex& parent = QModelIndex()) const;
-    virtual int rowCount(const QModelIndex& parent = QModelIndex()) const;
-    virtual QModelIndex parent(const QModelIndex& child) const;
-    virtual QModelIndex index(int row, int column, const QModelIndex& parent = QModelIndex()) const;
-    virtual QHash<int, QByteArray> roleNames() const;
+    QVariant data(const QModelIndex& index, int role = Qt::DisplayRole) const override;
+    int columnCount(const QModelIndex& parent = QModelIndex()) const override;
+    int rowCount(const QModelIndex& parent = QModelIndex()) const override;
+    QModelIndex parent(const QModelIndex& child) const override;
+    QModelIndex index(int row, int column, const QModelIndex& parent = QModelIndex()) const override;
+    QHash<int, QByteArray> roleNames() const override;
     Q_INVOKABLE QString longestCaption() const;
 
     /**
diff --git a/tabbox/switcheritem.h b/tabbox/switcheritem.h
--- a/tabbox/switcheritem.h
+++ b/tabbox/switcheritem.h
@@ -48,7 +48,7 @@
     Q_CLASSINFO("DefaultProperty", "item")
 public:
     SwitcherItem(QObject *parent = nullptr);
-    virtual ~SwitcherItem();
+    ~SwitcherItem() override;
 
     QAbstractItemModel *model() const;
     QRect screenGeometry() const;
diff --git a/tabbox/tabbox.h b/tabbox/tabbox.h
--- a/tabbox/tabbox.h
+++ b/tabbox/tabbox.h
@@ -51,27 +51,27 @@
 {
 public:
     explicit TabBoxHandlerImpl(TabBox* tabBox);
-    virtual ~TabBoxHandlerImpl();
-
-    virtual int activeScreen() const;
-    virtual QWeakPointer< TabBoxClient > activeClient() const;
-    virtual int currentDesktop() const;
-    virtual QString desktopName(TabBoxClient* client) const;
-    virtual QString desktopName(int desktop) const;
-    virtual bool isKWinCompositing() const;
-    virtual QWeakPointer< TabBoxClient > nextClientFocusChain(TabBoxClient* client) const;
-    virtual QWeakPointer< TabBoxClient > firstClientFocusChain() const;
-    virtual bool isInFocusChain (TabBoxClient* client) const;
-    virtual int nextDesktopFocusChain(int desktop) const;
-    virtual int numberOfDesktops() const;
-    virtual TabBoxClientList stackingOrder() const;
-    virtual void elevateClient(TabBoxClient* c, QWindow *tabbox, bool elevate) const;
-    virtual void raiseClient(TabBoxClient *client) const;
-    virtual void restack(TabBoxClient *c, TabBoxClient *under);
-    virtual void shadeClient(TabBoxClient *c, bool b) const;
-    virtual QWeakPointer< TabBoxClient > clientToAddToList(KWin::TabBox::TabBoxClient* client, int desktop) const;
-    virtual QWeakPointer< TabBoxClient > desktopClient() const;
-    virtual void activateAndClose();
+    ~TabBoxHandlerImpl() override;
+
+    int activeScreen() const override;
+    QWeakPointer< TabBoxClient > activeClient() const override;
+    int currentDesktop() const override;
+    QString desktopName(TabBoxClient* client) const override;
+    QString desktopName(int desktop) const override;
+    bool isKWinCompositing() const override;
+    QWeakPointer< TabBoxClient > nextClientFocusChain(TabBoxClient* client) const override;
+    QWeakPointer< TabBoxClient > firstClientFocusChain() const override;
+    bool isInFocusChain (TabBoxClient* client) const override;
+    int nextDesktopFocusChain(int desktop) const override;
+    int numberOfDesktops() const override;
+    TabBoxClientList stackingOrder() const override;
+    void elevateClient(TabBoxClient* c, QWindow *tabbox, bool elevate) const override;
+    void raiseClient(TabBoxClient *client) const override;
+    void restack(TabBoxClient *c, TabBoxClient *under) override;
+    void shadeClient(TabBoxClient *c, bool b) const override;
+    QWeakPointer< TabBoxClient > clientToAddToList(KWin::TabBox::TabBoxClient* client, int desktop) const override;
+    QWeakPointer< TabBoxClient > desktopClient() const override;
+    void activateAndClose() override;
     void highlightWindows(TabBoxClient *window = nullptr, QWindow *controller = nullptr) override;
     bool noModifierGrab() const override;
 
@@ -90,19 +90,19 @@
 {
 public:
     explicit TabBoxClientImpl(AbstractClient *client);
-    virtual ~TabBoxClientImpl();
-
-    virtual QString caption() const;
-    virtual QIcon icon() const override;
-    virtual WId window() const;
-    virtual bool isMinimized() const;
-    virtual int x() const;
-    virtual int y() const;
-    virtual int width() const;
-    virtual int height() const;
-    virtual bool isCloseable() const;
-    virtual void close();
-    virtual bool isFirstInTabBox() const;
+    ~TabBoxClientImpl() override;
+
+    QString caption() const override;
+    QIcon icon() const override;
+    WId window() const override;
+    bool isMinimized() const override;
+    int x() const override;
+    int y() const override;
+    int width() const override;
+    int height() const override;
+    bool isCloseable() const override;
+    void close() override;
+    bool isFirstInTabBox() const override;
     QUuid internalId() const override;
 
     AbstractClient* client() const {
@@ -117,7 +117,7 @@
 {
     Q_OBJECT
 public:
-    ~TabBox();
+    ~TabBox() override;
 
     /**
      * Returns the currently displayed client ( only works in TabBoxWindowsMode ).
diff --git a/tabbox/tabboxhandler.h b/tabbox/tabboxhandler.h
--- a/tabbox/tabboxhandler.h
+++ b/tabbox/tabboxhandler.h
@@ -96,7 +96,7 @@
     Q_OBJECT
 public:
     TabBoxHandler(QObject *parent);
-    virtual ~TabBoxHandler();
+    ~TabBoxHandler() override;
 
     /**
      * @return The id of the active screen
diff --git a/tabletmodemanager.h b/tabletmodemanager.h
--- a/tabletmodemanager.h
+++ b/tabletmodemanager.h
@@ -36,7 +36,7 @@
     Q_PROPERTY(bool tabletMode READ isTablet NOTIFY tabletModeChanged)
 
 public:
-    ~TabletModeManager() = default;
+    ~TabletModeManager() override = default;
 
     void setTabletModeAvailable(bool detecting);
     bool isTabletModeAvailable() const;
diff --git a/tests/cursorhotspottest.cpp b/tests/cursorhotspottest.cpp
--- a/tests/cursorhotspottest.cpp
+++ b/tests/cursorhotspottest.cpp
@@ -28,7 +28,7 @@
     Q_OBJECT
 public:
     explicit MouseCursorWidget();
-    ~MouseCursorWidget();
+    ~MouseCursorWidget() override;
 
 protected:
     void paintEvent(QPaintEvent * event) override;
diff --git a/tests/pointergesturestest.cpp b/tests/pointergesturestest.cpp
--- a/tests/pointergesturestest.cpp
+++ b/tests/pointergesturestest.cpp
@@ -38,7 +38,7 @@
 
 public:
     explicit PinchGesture(QQuickItem *parent = nullptr);
-    virtual ~PinchGesture();
+    ~PinchGesture() override;
 
     qreal scale() const {
         return m_scale;
diff --git a/tests/screenedgeshowtest.cpp b/tests/screenedgeshowtest.cpp
--- a/tests/screenedgeshowtest.cpp
+++ b/tests/screenedgeshowtest.cpp
@@ -51,7 +51,7 @@
     virtual void restore() = 0;
 
 public:
-    virtual ~ScreenEdgeHelper();
+    ~ScreenEdgeHelper() override;
 
     virtual void hide() = 0;
     virtual void raiseOrShow(bool raise) = 0;
@@ -78,7 +78,7 @@
     Q_OBJECT
 public:
     ScreenEdgeHelperX11(QWidget *widget, QObject *parent = nullptr);
-    virtual ~ScreenEdgeHelperX11() = default;
+    ~ScreenEdgeHelperX11() override = default;
 
     void hide() override;
     void raiseOrShow(bool raise) override;
@@ -103,7 +103,7 @@
     Q_OBJECT
 public:
     ScreenEdgeHelperWayland(QWidget *widget, QObject *parent = nullptr);
-    virtual ~ScreenEdgeHelperWayland() = default;
+    ~ScreenEdgeHelperWayland() override = default;
 
     void hide() override;
     void raiseOrShow(bool raise) override;
diff --git a/tests/waylandclienttest.h b/tests/waylandclienttest.h
--- a/tests/waylandclienttest.h
+++ b/tests/waylandclienttest.h
@@ -46,7 +46,7 @@
     Q_OBJECT
 public:
     explicit WaylandClientTest(QObject *parent = nullptr);
-    virtual ~WaylandClientTest();
+    ~WaylandClientTest() override;
 
 private:
     void init();
diff --git a/thumbnailitem.h b/thumbnailitem.h
--- a/thumbnailitem.h
+++ b/thumbnailitem.h
@@ -40,7 +40,7 @@
     Q_PROPERTY(qreal saturation READ saturation WRITE setSaturation NOTIFY saturationChanged)
     Q_PROPERTY(QQuickItem *clipTo READ clipTo WRITE setClipTo NOTIFY clipToChanged)
 public:
-    virtual ~AbstractThumbnailItem();
+    ~AbstractThumbnailItem() override;
     qreal brightness() const;
     qreal saturation() const;
     QQuickItem *clipTo() const;
@@ -81,20 +81,20 @@
     Q_PROPERTY(KWin::AbstractClient *client READ client WRITE setClient NOTIFY clientChanged)
 public:
     explicit WindowThumbnailItem(QQuickItem *parent = 0);
-    virtual ~WindowThumbnailItem();
+    ~WindowThumbnailItem() override;
 
     QUuid wId() const {
         return m_wId;
     }
     void setWId(const QUuid &wId);
     AbstractClient *client() const;
     void setClient(AbstractClient *client);
-    virtual void paint(QPainter *painter);
+    void paint(QPainter *painter) override;
 Q_SIGNALS:
     void wIdChanged(const QUuid &wid);
     void clientChanged();
 protected Q_SLOTS:
-    virtual void repaint(KWin::EffectWindow* w);
+    void repaint(KWin::EffectWindow* w) override;
 private:
     QUuid m_wId;
     AbstractClient *m_client;
@@ -106,17 +106,17 @@
     Q_PROPERTY(int desktop READ desktop WRITE setDesktop NOTIFY desktopChanged)
 public:
     DesktopThumbnailItem(QQuickItem *parent = 0);
-    virtual ~DesktopThumbnailItem();
+    ~DesktopThumbnailItem() override;
 
     int desktop() const {
         return m_desktop;
     }
     void setDesktop(int desktop);
-    virtual void paint(QPainter *painter);
+    void paint(QPainter *painter) override;
 Q_SIGNALS:
     void desktopChanged(int desktop);
 protected Q_SLOTS:
-    virtual void repaint(KWin::EffectWindow* w);
+    void repaint(KWin::EffectWindow* w) override;
 private:
     int m_desktop;
 };
diff --git a/toplevel.h b/toplevel.h
--- a/toplevel.h
+++ b/toplevel.h
@@ -583,7 +583,7 @@
     void setReadyForPainting();
 
 protected:
-    virtual ~Toplevel();
+    ~Toplevel() override;
     void setWindowHandles(xcb_window_t client);
     void detectShape(Window id);
     virtual void propertyNotifyEvent(xcb_property_notify_event_t *e);
diff --git a/touch_input.h b/touch_input.h
--- a/touch_input.h
+++ b/touch_input.h
@@ -48,11 +48,11 @@
     Q_OBJECT
 public:
     explicit TouchInputRedirection(InputRedirection *parent);
-    virtual ~TouchInputRedirection();
+    ~TouchInputRedirection() override;
 
     bool positionValid() const override;
     bool focusUpdatesBlocked() override;
-    void init();
+    void init() override;
 
     void processDown(qint32 id, const QPointF &pos, quint32 time, LibInput::Device *device = nullptr);
     void processUp(qint32 id, quint32 time, LibInput::Device *device = nullptr);
diff --git a/unmanaged.h b/unmanaged.h
--- a/unmanaged.h
+++ b/unmanaged.h
@@ -37,27 +37,27 @@
     bool windowEvent(xcb_generic_event_t *e);
     bool track(Window w);
     static void deleteUnmanaged(Unmanaged* c);
-    virtual int desktop() const;
-    virtual QStringList activities() const;
-    virtual QVector<VirtualDesktop *> desktops() const override;
-    virtual QPoint clientPos() const;
-    virtual QSize clientSize() const;
-    virtual QRect transparentRect() const;
-    virtual Layer layer() const {
+    int desktop() const override;
+    QStringList activities() const override;
+    QVector<VirtualDesktop *> desktops() const override;
+    QPoint clientPos() const override;
+    QSize clientSize() const override;
+    QRect transparentRect() const override;
+    Layer layer() const override {
         return UnmanagedLayer;
     }
-    NET::WindowType windowType(bool direct = false, int supported_types = 0) const;
+    NET::WindowType windowType(bool direct = false, int supported_types = 0) const override;
     bool isOutline() const override;
 
     bool setupCompositing() override;
 
 public Q_SLOTS:
     void release(ReleaseReason releaseReason = ReleaseReason::Release);
 protected:
-    virtual void debug(QDebug& stream) const;
+    void debug(QDebug& stream) const override;
     void addDamage(const QRegion &damage) override;
 private:
-    virtual ~Unmanaged(); // use release()
+    ~Unmanaged() override; // use release()
     // handlers for X11 events
     void configureNotifyEvent(xcb_configure_notify_event_t *e);
     QWindow *findInternalWindow() const;
diff --git a/useractions.h b/useractions.h
--- a/useractions.h
+++ b/useractions.h
@@ -59,7 +59,7 @@
     Q_OBJECT
 public:
     explicit UserActionsMenu(QObject *parent = 0);
-    virtual ~UserActionsMenu();
+    ~UserActionsMenu() override;
     /**
      * Discards the constructed menu, so that it gets recreates
      * on next show event.
@@ -285,14 +285,14 @@
     Q_OBJECT
 public:
     explicit ShortcutDialog(const QKeySequence& cut);
-    virtual void accept();
+    void accept() override;
     QKeySequence shortcut() const;
 public Q_SLOTS:
     void keySequenceChanged();
 Q_SIGNALS:
     void dialogDone(bool ok);
 protected:
-    virtual void done(int r);
+    void done(int r) override;
 private:
     Ui::ShortcutDialog m_ui;
     QKeySequence _shortcut;
diff --git a/utils.h b/utils.h
--- a/utils.h
+++ b/utils.h
@@ -232,7 +232,7 @@
     Q_OBJECT
 public:
     explicit Process(QObject *parent = nullptr);
-    virtual ~Process();
+    ~Process() override;
 
 protected:
     void setupChildProcess() override;
diff --git a/virtual_terminal.h b/virtual_terminal.h
--- a/virtual_terminal.h
+++ b/virtual_terminal.h
@@ -32,7 +32,7 @@
 {
     Q_OBJECT
 public:
-    virtual ~VirtualTerminal();
+    ~VirtualTerminal() override;
 
     void init();
     void activate(int vt);
diff --git a/virtualdesktops.h b/virtualdesktops.h
--- a/virtualdesktops.h
+++ b/virtualdesktops.h
@@ -54,7 +54,7 @@
     Q_PROPERTY(QString name READ name WRITE setName NOTIFY nameChanged)
 public:
     explicit VirtualDesktop(QObject *parent = nullptr);
-    virtual ~VirtualDesktop();
+    ~VirtualDesktop() override;
 
     void setId(const QByteArray &id);
     QByteArray id() const {
@@ -156,7 +156,7 @@
      **/
     Q_PROPERTY(bool navigationWrappingAround READ isNavigationWrappingAround WRITE setNavigationWrappingAround NOTIFY navigationWrappingAroundChanged)
 public:
-    virtual ~VirtualDesktopManager();
+    ~VirtualDesktopManager() override;
     /**
      * @internal, for X11 case
      **/
diff --git a/virtualkeyboard.h b/virtualkeyboard.h
--- a/virtualkeyboard.h
+++ b/virtualkeyboard.h
@@ -39,7 +39,7 @@
 {
     Q_OBJECT
 public:
-    virtual ~VirtualKeyboard();
+    ~VirtualKeyboard() override;
 
     void init();
 
diff --git a/virtualkeyboard_dbus.h b/virtualkeyboard_dbus.h
--- a/virtualkeyboard_dbus.h
+++ b/virtualkeyboard_dbus.h
@@ -31,7 +31,7 @@
     Q_PROPERTY(bool enabled READ isEnabled NOTIFY enabledChanged)
 public:
     explicit VirtualKeyboardDBus(QObject *parent = nullptr);
-    ~VirtualKeyboardDBus();
+    ~VirtualKeyboardDBus() override;
     Q_INVOKABLE bool isEnabled() const {
         return m_enabled;
     }
diff --git a/wayland_cursor_theme.h b/wayland_cursor_theme.h
--- a/wayland_cursor_theme.h
+++ b/wayland_cursor_theme.h
@@ -44,7 +44,7 @@
     Q_OBJECT
 public:
     explicit WaylandCursorTheme(KWayland::Client::ShmPool *shm, QObject *parent = nullptr);
-    virtual ~WaylandCursorTheme();
+    ~WaylandCursorTheme() override;
 
     wl_cursor_image *get(CursorShape shape);
     wl_cursor_image *get(const QByteArray &name);
diff --git a/wayland_server.h b/wayland_server.h
--- a/wayland_server.h
+++ b/wayland_server.h
@@ -91,7 +91,7 @@
 
     Q_DECLARE_FLAGS(InitalizationFlags, InitalizationFlag)
 
-    virtual ~WaylandServer();
+    ~WaylandServer() override;
     bool init(const QByteArray &socketName = QByteArray(), InitalizationFlags flags = InitalizationFlag::NoOptions);
     void terminateClientConnections();
 
diff --git a/workspace.h b/workspace.h
--- a/workspace.h
+++ b/workspace.h
@@ -66,7 +66,7 @@
     Q_OBJECT
 public:
     explicit Workspace(const QString &sessionKey = QString());
-    virtual ~Workspace();
+    ~Workspace() override;
 
     static Workspace* self() {
         return _self;
@@ -664,7 +664,7 @@
     Q_OBJECT
 public:
     ColorMapper(QObject *parent);
-    virtual ~ColorMapper();
+    ~ColorMapper() override;
 public Q_SLOTS:
     void update();
 private:
diff --git a/xkb.h b/xkb.h
--- a/xkb.h
+++ b/xkb.h
@@ -54,7 +54,7 @@
     Q_OBJECT
 public:
     Xkb(QObject *parent = nullptr);
-    ~Xkb();
+    ~Xkb() override;
     void setConfig(KSharedConfigPtr config) {
         m_config = config;
     }
diff --git a/xwl/databridge.h b/xwl/databridge.h
--- a/xwl/databridge.h
+++ b/xwl/databridge.h
@@ -65,7 +65,7 @@
     static DataBridge *self();
 
     explicit DataBridge(QObject *parent = nullptr);
-    ~DataBridge();
+    ~DataBridge() override;
 
     bool filterEvent(xcb_generic_event_t *event);
     DragEventReply dragMoveFilter(Toplevel *target, const QPoint &pos);
diff --git a/xwl/drag_x.h b/xwl/drag_x.h
--- a/xwl/drag_x.h
+++ b/xwl/drag_x.h
@@ -103,7 +103,7 @@
 
 public:
     WlVisit(AbstractClient *target, XToWlDrag *drag);
-    ~WlVisit();
+    ~WlVisit() override;
 
     bool handleClientMessage(xcb_client_message_event_t *event);
     bool leave();
diff --git a/xwl/transfer.h b/xwl/transfer.h
--- a/xwl/transfer.h
+++ b/xwl/transfer.h
@@ -121,7 +121,7 @@
                   xcb_selection_request_event_t *request,
                   qint32 fd,
                   QObject *parent = nullptr);
-    ~TransferWltoX();
+    ~TransferWltoX() override;
 
     void startTransferFromSource();
     bool handlePropertyNotify(xcb_property_notify_event_t *event) override;
@@ -208,7 +208,7 @@
                   qint32 fd,
                   xcb_timestamp_t timestamp, xcb_window_t parentWindow,
                   QObject *parent = nullptr);
-    ~TransferXtoWl();
+    ~TransferXtoWl() override;
 
     bool handleSelectionNotify(xcb_selection_notify_event_t *event);
     bool handlePropertyNotify(xcb_property_notify_event_t *event) override;
diff --git a/xwl/xwayland_interface.h b/xwl/xwayland_interface.h
--- a/xwl/xwayland_interface.h
+++ b/xwl/xwayland_interface.h
@@ -52,7 +52,7 @@
 
 protected:
     explicit XwaylandInterface(QObject *parent = nullptr);
-    virtual ~XwaylandInterface();
+    ~XwaylandInterface() override;
 
 private:
     Q_DISABLE_COPY(XwaylandInterface)