diff --git a/composite.h b/composite.h
--- a/composite.h
+++ b/composite.h
@@ -113,10 +113,6 @@
         return s_compositor != NULL && s_compositor->isActive();
     }
 
-
-    virtual void updateCompositeBlocking() = 0;
-    virtual void updateClientCompositeBlocking(KWin::Client *c) = 0;
-
     // for delayed supportproperty management of effects
     void keepSupportProperty(xcb_atom_t atom);
     void removeSupportProperty(xcb_atom_t atom);
@@ -197,9 +193,6 @@
 
     bool checkForOverlayWindow(WId w) const override;
 
-    void updateCompositeBlocking() override;
-    void updateClientCompositeBlocking(KWin::Client* c) override;
-
 protected:
     void start() override;
 
@@ -267,8 +260,9 @@
 
     int refreshRate() const override;
 
-    void updateCompositeBlocking() override;
-    void updateClientCompositeBlocking(KWin::Client* c) override;
+    void updateClientCompositeBlocking(Client *client = nullptr);
+
+    static X11Compositor *self();
 
 protected:
     void start() override;
diff --git a/composite.cpp b/composite.cpp
--- a/composite.cpp
+++ b/composite.cpp
@@ -890,17 +890,6 @@
     return KWin::currentRefreshRate();
 }
 
-void WaylandCompositor::updateCompositeBlocking()
-{
-    // Composite blocking not possible on Wayland.
-}
-
-void WaylandCompositor::updateClientCompositeBlocking(Client *c)
-{
-    Q_UNUSED(c)
-    // Composite blocking not possible on Wayland.
-}
-
 X11Compositor::X11Compositor(QObject *parent)
     : Compositor(parent)
     , m_suspended(options->isUseCompositing() ? NoReasonSuspend : UserSuspend)
@@ -1029,11 +1018,6 @@
     return m_xrrRefreshRate;
 }
 
-void X11Compositor::updateCompositeBlocking()
-{
-    updateClientCompositeBlocking(NULL);
-}
-
 void X11Compositor::updateClientCompositeBlocking(Client *c)
 {
     if (c) {
@@ -1063,6 +1047,11 @@
     }
 }
 
+X11Compositor *X11Compositor::self()
+{
+    return qobject_cast<X11Compositor *>(Compositor::self());
+}
+
 }
 
 // included for CompositorSelectionOwner
diff --git a/workspace.cpp b/workspace.cpp
--- a/workspace.cpp
+++ b/workspace.cpp
@@ -596,7 +596,9 @@
     StackingUpdatesBlocker blocker(this);
     Client* c = new Client();
     setupClientConnections(c);
-    connect(c, &Client::blockingCompositingChanged, m_compositor, &Compositor::updateClientCompositeBlocking);
+    if (X11Compositor *compositor = X11Compositor::self()) {
+        connect(c, &Client::blockingCompositingChanged, compositor, &X11Compositor::updateClientCompositeBlocking);
+    }
     connect(c, SIGNAL(clientFullScreenSet(KWin::Client*,bool,bool)), ScreenEdges::self(), SIGNAL(checkBlocking()));
     if (!c->manage(w, is_mapped)) {
         Client::deleteClient(c);
@@ -749,8 +751,11 @@
     unconstrained_stacking_order.removeAll(c);
     stacking_order.removeAll(c);
     markXStackingOrderAsDirty();
-    if (c->wasClient() && m_compositor) {
-        m_compositor->updateCompositeBlocking();
+    if (!c->wasClient()) {
+        return;
+    }
+    if (X11Compositor *compositor = X11Compositor::self()) {
+        compositor->updateClientCompositeBlocking();
     }
 }