diff --git a/src/client/protocols/server-decoration.xml b/src/client/protocols/server-decoration.xml
--- a/src/client/protocols/server-decoration.xml
+++ b/src/client/protocols/server-decoration.xml
@@ -40,6 +40,23 @@
         <arg name="id" type="new_id" interface="org_kde_kwin_server_decoration"/>
         <arg name="surface" type="object" interface="wl_surface"/>
       </request>
+      <enum name="mode">
+            <description summary="Possible values to use in request_mode and the event mode."/>
+            <entry name="None" value="0" summary="Undecorated: The surface is not decorated at all, neither server nor client-side. An example is a popup surface which should not be decorated."/>
+            <entry name="Client" value="1" summary="Client-side decoration: The decoration is part of the surface and the client."/>
+            <entry name="Server" value="2" summary="Server-side decoration: The server embeds the surface into a decoration frame."/>
+      </enum>
+      <event name="default_mode">
+          <description summary="The default mode used on the server">
+              This event is emitted directly after binding the interface. It contains
+              the default mode for the decoration. When a new server decoration object
+              is created this new object will be in the default mode till the first
+              request mode is emitted.
+
+              The server may change the default mode at any time.
+          </description>
+          <arg name="mode" type="uint" summary="The default decoration mode applied to newly created server decorations."/>
+      </event>
   </interface>
   <interface name="org_kde_kwin_server_decoration" version="1">
       <request name="release" type="destructor">
diff --git a/src/client/server_decoration.h b/src/client/server_decoration.h
--- a/src/client/server_decoration.h
+++ b/src/client/server_decoration.h
@@ -222,6 +222,13 @@
      **/
     Mode mode() const;
 
+    /**
+     * @returns The default decoration mode the server uses
+     *
+     * @see mode
+     **/
+    Mode defaultMode() const;
+
     operator org_kde_kwin_server_decoration*();
     operator org_kde_kwin_server_decoration*() const;
 
diff --git a/src/client/server_decoration.cpp b/src/client/server_decoration.cpp
--- a/src/client/server_decoration.cpp
+++ b/src/client/server_decoration.cpp
@@ -24,7 +24,8 @@
 #include "wayland_pointer_p.h"
 
 #include <wayland-server-decoration-client-protocol.h>
-class ServerSideDe;
+
+#include <QVector>
 
 namespace KWayland
 {
@@ -36,10 +37,79 @@
 public:
     Private() = default;
 
+    void setup(org_kde_kwin_server_decoration_manager *serversidedecorationmanager);
+
     WaylandPointer<org_kde_kwin_server_decoration_manager, org_kde_kwin_server_decoration_manager_destroy> serversidedecorationmanager;
     EventQueue *queue = nullptr;
+    ServerSideDecoration::Mode defaultMode = ServerSideDecoration::Mode::None;
+    QVector<ServerSideDecoration*> decorations;
+
+private:
+    static void defaultModeCallback(void *data, org_kde_kwin_server_decoration_manager *manager, uint32_t mode);
+    static const struct org_kde_kwin_server_decoration_manager_listener s_listener;
 };
 
+class ServerSideDecoration::Private
+{
+public:
+    Private(ServerSideDecoration *q);
+
+    void setup(org_kde_kwin_server_decoration *serversidedecoration);
+
+    WaylandPointer<org_kde_kwin_server_decoration, org_kde_kwin_server_decoration_release> serversidedecoration;
+    Mode mode = Mode::None;
+    Mode defaultMode = Mode::None;
+
+private:
+    static void modeCallback(void *data, org_kde_kwin_server_decoration *org_kde_kwin_server_decoration, uint32_t mode);
+    static const struct org_kde_kwin_server_decoration_listener s_listener;
+
+    ServerSideDecoration *q;
+};
+
+#ifndef DOXYGEN_SHOULD_SKIP_THIS
+const org_kde_kwin_server_decoration_manager_listener ServerSideDecorationManager::Private::s_listener = {
+    defaultModeCallback
+};
+#endif
+
+void ServerSideDecorationManager::Private::defaultModeCallback(void *data, org_kde_kwin_server_decoration_manager *manager, uint32_t mode)
+{
+    auto p = reinterpret_cast<ServerSideDecorationManager::Private*>(data);
+    Q_ASSERT(p->serversidedecorationmanager == manager);
+
+    ServerSideDecoration::Mode m;
+    switch (mode) {
+    case ORG_KDE_KWIN_SERVER_DECORATION_MODE_NONE:
+        m = ServerSideDecoration::Mode::None;
+        break;
+    case ORG_KDE_KWIN_SERVER_DECORATION_MODE_CLIENT:
+        m = ServerSideDecoration::Mode::Client;
+        break;
+    case ORG_KDE_KWIN_SERVER_DECORATION_MODE_SERVER:
+        m = ServerSideDecoration::Mode::Server;
+        break;
+    default:
+        // invalid mode cannot set
+        qCWarning(KWAYLAND_CLIENT) << "Invalid decoration mode pushed by Server:" << mode;
+        return;
+    }
+    p->defaultMode = m;
+    // update the default mode on all decorations
+    for (auto it = p->decorations.constBegin(); it != p->decorations.constEnd(); ++it) {
+        (*it)->d->defaultMode = m;
+        // TODO: do we need a signal?
+    }
+}
+
+void ServerSideDecorationManager::Private::setup(org_kde_kwin_server_decoration_manager *manager)
+{
+    Q_ASSERT(manager);
+    Q_ASSERT(!serversidedecorationmanager);
+    serversidedecorationmanager.setup(manager);
+    org_kde_kwin_server_decoration_manager_add_listener(serversidedecorationmanager, &s_listener, this);
+}
+
 ServerSideDecorationManager::ServerSideDecorationManager(QObject *parent)
     : QObject(parent)
     , d(new Private)
@@ -53,9 +123,7 @@
 
 void ServerSideDecorationManager::setup(org_kde_kwin_server_decoration_manager *serversidedecorationmanager)
 {
-    Q_ASSERT(serversidedecorationmanager);
-    Q_ASSERT(!d->serversidedecorationmanager);
-    d->serversidedecorationmanager.setup(serversidedecorationmanager);
+    d->setup(serversidedecorationmanager);
 }
 
 void ServerSideDecorationManager::release()
@@ -104,27 +172,12 @@
     if (d->queue) {
         d->queue->addProxy(w);
     }
+    deco->d->defaultMode = d->defaultMode;
+    deco->d->mode = d->defaultMode;
     deco->setup(w);
     return deco;
 }
 
-class ServerSideDecoration::Private
-{
-public:
-    Private(ServerSideDecoration *q);
-
-    void setup(org_kde_kwin_server_decoration *serversidedecoration);
-
-    WaylandPointer<org_kde_kwin_server_decoration, org_kde_kwin_server_decoration_release> serversidedecoration;
-    Mode mode = Mode::None;
-
-private:
-    static void modeCallback(void *data, org_kde_kwin_server_decoration *org_kde_kwin_server_decoration, uint32_t mode);
-    static const struct org_kde_kwin_server_decoration_listener s_listener;
-
-    ServerSideDecoration *q;
-};
-
 #ifndef DOXYGEN_SHOULD_SKIP_THIS
 const org_kde_kwin_server_decoration_listener ServerSideDecoration::Private::s_listener = {
     modeCallback
@@ -232,5 +285,10 @@
     return d->mode;
 }
 
+ServerSideDecoration::Mode ServerSideDecoration::defaultMode() const
+{
+    return d->defaultMode;
+}
+
 }
 }
diff --git a/src/server/server_decoration_interface.cpp b/src/server/server_decoration_interface.cpp
--- a/src/server/server_decoration_interface.cpp
+++ b/src/server/server_decoration_interface.cpp
@@ -40,6 +40,8 @@
 
     Mode defaultMode = Mode::None;
 
+    QVector<wl_resource*> resources;
+
 private:
     void bind(wl_client *client, uint32_t version, uint32_t id) override;
 
@@ -107,6 +109,25 @@
 {
 }
 
+namespace {
+static uint32_t modeWayland(ServerSideDecorationManagerInterface::Mode mode)
+{
+    switch (mode) {
+    case ServerSideDecorationManagerInterface::Mode::None:
+        return ORG_KDE_KWIN_SERVER_DECORATION_MODE_NONE;
+        break;
+    case ServerSideDecorationManagerInterface::Mode::Client:
+        return ORG_KDE_KWIN_SERVER_DECORATION_MODE_CLIENT;
+        break;
+    case ServerSideDecorationManagerInterface::Mode::Server:
+        return ORG_KDE_KWIN_SERVER_DECORATION_MODE_SERVER;
+        break;
+    default:
+        Q_UNREACHABLE();
+    }
+}
+}
+
 void ServerSideDecorationManagerInterface::Private::bind(wl_client *client, uint32_t version, uint32_t id)
 {
     auto c = display->getConnection(client);
@@ -116,13 +137,16 @@
         return;
     }
     wl_resource_set_implementation(resource, &s_interface, this, unbind);
-    // TODO: should we track?
+
+    resources << resource;
+
+    org_kde_kwin_server_decoration_manager_send_default_mode(resource, modeWayland(defaultMode));
+    c->flush();
 }
 
 void ServerSideDecorationManagerInterface::Private::unbind(wl_resource *resource)
 {
-    Q_UNUSED(resource)
-    // TODO: implement?
+    cast(resource)->resources.removeAll(resource);
 }
 
 ServerSideDecorationManagerInterface::ServerSideDecorationManagerInterface(Display *display, QObject *parent)
@@ -141,6 +165,10 @@
 {
     Q_D();
     d->defaultMode = mode;
+    const uint32_t wlMode = modeWayland(mode);
+    for (auto it = d->resources.constBegin(); it != d->resources.constEnd(); it++) {
+        org_kde_kwin_server_decoration_manager_send_default_mode(*it, wlMode);
+    }
 }
 
 class ServerSideDecorationInterface::Private : public Resource::Private
@@ -240,21 +268,7 @@
 {
     Q_D();
     d->mode = mode;
-    uint32_t wlMode;
-    switch (mode) {
-    case ServerSideDecorationManagerInterface::Mode::None:
-        wlMode = ORG_KDE_KWIN_SERVER_DECORATION_MODE_NONE;
-        break;
-    case ServerSideDecorationManagerInterface::Mode::Client:
-        wlMode = ORG_KDE_KWIN_SERVER_DECORATION_MODE_CLIENT;
-        break;
-    case ServerSideDecorationManagerInterface::Mode::Server:
-        wlMode = ORG_KDE_KWIN_SERVER_DECORATION_MODE_SERVER;
-        break;
-    default:
-        Q_UNREACHABLE();
-    }
-    org_kde_kwin_server_decoration_send_mode(resource(), wlMode);
+    org_kde_kwin_server_decoration_send_mode(resource(), modeWayland(mode));
     client()->flush();
 }