diff --git a/abstract_client.h b/abstract_client.h
--- a/abstract_client.h
+++ b/abstract_client.h
@@ -787,6 +787,7 @@
      * Implementing subclasses can perform a windowing system solution for terminating.
      */
     virtual void killWindow() = 0;
+    virtual void destroyClient() = 0;
 
     enum class SameApplicationCheck {
         RelaxedForActive = 1 << 0,
diff --git a/internal_client.h b/internal_client.h
--- a/internal_client.h
+++ b/internal_client.h
@@ -81,8 +81,8 @@
     void updateDecoration(bool check_workspace_pos, bool force = false) override;
     void updateColorScheme() override;
     void showOnScreenEdge() override;
+    void destroyClient() override;
 
-    void destroyClient();
     void present(const QSharedPointer<QOpenGLFramebufferObject> fbo);
     void present(const QImage &image, const QRegion &damage);
     QWindow *internalWindow() const;
diff --git a/workspace.cpp b/workspace.cpp
--- a/workspace.cpp
+++ b/workspace.cpp
@@ -56,7 +56,6 @@
 #include "unmanaged.h"
 #include "useractions.h"
 #include "virtualdesktops.h"
-#include "xdgshellclient.h"
 #include "was_user_interaction_x11_filter.h"
 #include "wayland_server.h"
 #include "xcbutils.h"
@@ -473,12 +472,9 @@
     X11Client::cleanupX11();
 
     if (waylandServer()) {
-        // TODO: Introduce AbstractClient::destroy().
         const QList<AbstractClient *> shellClients = waylandServer()->clients();
         for (AbstractClient *client : shellClients) {
-            if (XdgShellClient *shellClient = qobject_cast<XdgShellClient *>(client)) {
-                shellClient->destroyClient();
-            }
+            client->destroyClient();
         }
     }
 
diff --git a/x11client.h b/x11client.h
--- a/x11client.h
+++ b/x11client.h
@@ -129,7 +129,7 @@
 
     bool manage(xcb_window_t w, bool isMapped);
     void releaseWindow(bool on_shutdown = false);
-    void destroyClient();
+    void destroyClient() override;
 
     QStringList activities() const override;
     void setOnActivity(const QString &activity, bool enable);
diff --git a/xdgshellclient.h b/xdgshellclient.h
--- a/xdgshellclient.h
+++ b/xdgshellclient.h
@@ -121,6 +121,7 @@
     void killWindow() override;
     bool isLocalhost() const override;
     bool supportsWindowRules() const override;
+    void destroyClient() override;
 
     void installPlasmaShellSurface(KWayland::Server::PlasmaShellSurfaceInterface *surface);
     void installServerSideDecoration(KWayland::Server::ServerSideDecorationInterface *decoration);
@@ -170,7 +171,6 @@
      */
     void finishInit();
     void createDecoration(const QRect &oldgeom);
-    void destroyClient();
     void createWindowId();
     void updateIcon();
     bool shouldExposeToWindowManagement();