diff --git a/autotests/kstartupinfo_unittest.cpp b/autotests/kstartupinfo_unittest.cpp
--- a/autotests/kstartupinfo_unittest.cpp
+++ b/autotests/kstartupinfo_unittest.cpp
@@ -272,7 +272,7 @@
                         wmClass.length() * 2 + 1,
                         "kstartupinfotest\0kstartupinfotest");
     xcb_change_property(c, XCB_PROP_MODE_REPLACE, window, XCB_ATOM_WM_CLIENT_MACHINE, XCB_ATOM_STRING, 8, 9, "localhost");
-    NETWinInfo winInfo(QX11Info::connection(), window, QX11Info::appRootWindow(), nullptr, nullptr);
+    NETWinInfo winInfo(QX11Info::connection(), window, QX11Info::appRootWindow(), NET::Properties(), NET::Properties2());
     winInfo.setPid(pid);
 
     KStartupInfo info(KStartupInfo::DisableKWinModule | KStartupInfo::AnnounceSilenceChanges, this);
diff --git a/autotests/kwindowinfox11test.cpp b/autotests/kwindowinfox11test.cpp
--- a/autotests/kwindowinfox11test.cpp
+++ b/autotests/kwindowinfox11test.cpp
@@ -502,7 +502,7 @@
     QSignalSpy spyReal(KWindowSystem::self(), static_cast<void (KWindowSystem::*)(WId,NET::Properties,NET::Properties2)>(&KWindowSystem::windowChanged));
     QVERIFY(spyReal.isValid());
 
-    KWindowInfo info(window->winId(), nullptr, NET::WM2Activities);
+    KWindowInfo info(window->winId(), NET::Properties(), NET::WM2Activities);
     QVERIFY(info.valid());
 
     QStringList startingActivities = info.activities();
@@ -517,16 +517,16 @@
 
     QVERIFY(waitForWindow(spyReal, window->winId(), NET::Properties(), NET::WM2Activities));
 
-    KWindowInfo info2(window->winId(), nullptr, NET::WM2Activities);
+    KWindowInfo info2(window->winId(), NET::Properties(), NET::WM2Activities);
 
     QVERIFY(info2.activities().size() == 0);
 
     // Window on a specific activity
     KWindowSystem::self()->setOnActivities(window->winId(), QStringList() << "test-activity");
 
     QVERIFY(waitForWindow(spyReal, window->winId(), NET::Properties(), NET::WM2Activities));
 
-    KWindowInfo info3(window->winId(), nullptr, NET::WM2Activities);
+    KWindowInfo info3(window->winId(), NET::Properties(), NET::WM2Activities);
 
     QVERIFY(info3.activities().size() == 1);
     QVERIFY(info3.activities()[0] == "test-activity");
@@ -536,7 +536,7 @@
 
     QVERIFY(waitForWindow(spyReal, window->winId(), NET::Properties(), NET::WM2Activities));
 
-    KWindowInfo info4(window->winId(), nullptr, NET::WM2Activities);
+    KWindowInfo info4(window->winId(), NET::Properties(), NET::WM2Activities);
 
     QVERIFY(info4.activities().size() == 2);
     QVERIFY(info4.activities()[0] == "test-activity");
@@ -547,14 +547,14 @@
 
     QVERIFY(waitForWindow(spyReal, window->winId(), NET::Properties(), NET::WM2Activities));
 
-    KWindowInfo info5(window->winId(), nullptr, NET::WM2Activities);
+    KWindowInfo info5(window->winId(), NET::Properties(), NET::WM2Activities);
 
     QVERIFY(info5.activities() == startingActivities);
 }
 
 void KWindowInfoX11Test::testWindowClass()
 {
-    KWindowInfo info(window->winId(), nullptr, NET::WM2WindowClass);
+    KWindowInfo info(window->winId(), NET::Properties(), NET::WM2WindowClass);
     QCOMPARE(info.windowClassName(), QByteArrayLiteral("kwindowinfox11test"));
     QCOMPARE(info.windowClassClass(), QByteArrayLiteral("kwindowinfox11test"));
 
@@ -566,14 +566,14 @@
     // it's just a property change so we can easily refresh
     QX11Info::getTimestamp();
 
-    KWindowInfo info2(window->winId(), nullptr, NET::WM2WindowClass);
+    KWindowInfo info2(window->winId(), NET::Properties(), NET::WM2WindowClass);
     QCOMPARE(info2.windowClassName(), QByteArrayLiteral("foo"));
     QCOMPARE(info2.windowClassClass(), QByteArrayLiteral("bar"));
 }
 
 void KWindowInfoX11Test::testWindowRole()
 {
-    KWindowInfo info(window->winId(), nullptr, NET::WM2WindowRole);
+    KWindowInfo info(window->winId(), NET::Properties(), NET::WM2WindowRole);
     QVERIFY(info.windowRole().isNull());
 
     // window role needs to be changed using xcb
@@ -585,13 +585,13 @@
     // it's just a property change so we can easily refresh
     QX11Info::getTimestamp();
 
-    KWindowInfo info2(window->winId(), nullptr, NET::WM2WindowRole);
+    KWindowInfo info2(window->winId(), NET::Properties(), NET::WM2WindowRole);
     QCOMPARE(info2.windowRole(), QByteArrayLiteral("bar"));
 }
 
 void KWindowInfoX11Test::testClientMachine()
 {
-    KWindowInfo info(window->winId(), nullptr, NET::WM2ClientMachine);
+    KWindowInfo info(window->winId(), NET::Properties(), NET::WM2ClientMachine);
     QVERIFY(info.clientMachine().isNull());
 
     // client machine needs to be set through xcb
@@ -602,7 +602,7 @@
     // it's just a property change so we can easily refresh
     QX11Info::getTimestamp();
 
-    KWindowInfo info2(window->winId(), nullptr, NET::WM2ClientMachine);
+    KWindowInfo info2(window->winId(), NET::Properties(), NET::WM2ClientMachine);
     QCOMPARE(info2.clientMachine(), QByteArrayLiteral("localhost"));
 }
 
@@ -637,7 +637,7 @@
     }
 
     // create a low level NETWinInfo to manipulate the name
-    NETWinInfo winInfo(QX11Info::connection(), window->winId(), QX11Info::appRootWindow(), NET::WMName, nullptr);
+    NETWinInfo winInfo(QX11Info::connection(), window->winId(), QX11Info::appRootWindow(), NET::WMName, NET::Properties2());
     winInfo.setName("foobar");
 
     QX11Info::getTimestamp();
@@ -653,7 +653,7 @@
 
 void KWindowInfoX11Test::testTransientFor()
 {
-    KWindowInfo info(window->winId(), nullptr, NET::WM2TransientFor);
+    KWindowInfo info(window->winId(), NET::Properties(), NET::WM2TransientFor);
     QCOMPARE(info.transientFor(), WId(0));
 
     // let's create a second window
@@ -667,22 +667,22 @@
                         XCB_ATOM_WM_TRANSIENT_FOR, XCB_ATOM_WINDOW, 32, 1, &id);
     xcb_flush(QX11Info::connection());
 
-    KWindowInfo info2(window->winId(), nullptr, NET::WM2TransientFor);
+    KWindowInfo info2(window->winId(), NET::Properties(), NET::WM2TransientFor);
     QCOMPARE(info2.transientFor(), window2->winId());
 }
 
 void KWindowInfoX11Test::testGroupLeader()
 {
-    KWindowInfo info(window->winId(), nullptr, NET::WM2GroupLeader);
+    KWindowInfo info(window->winId(), NET::Properties(), NET::WM2GroupLeader);
     QCOMPARE(info.groupLeader(), WId(0));
 
     // TODO: here we should try to set a group leader and re-read it
     // this needs setting and parsing the WMHints
 }
 
 void KWindowInfoX11Test::testExtendedStrut()
 {
-    KWindowInfo info(window->winId(), nullptr, NET::WM2ExtendedStrut);
+    KWindowInfo info(window->winId(), NET::Properties(), NET::WM2ExtendedStrut);
     NETExtendedStrut strut = info.extendedStrut();
     QCOMPARE(strut.bottom_end, 0);
     QCOMPARE(strut.bottom_start, 0);
@@ -702,7 +702,7 @@
     // it's just an xprop, so one roundtrip is good enough
     QX11Info::getTimestamp();
 
-    KWindowInfo info2(window->winId(), nullptr, NET::WM2ExtendedStrut);
+    KWindowInfo info2(window->winId(), NET::Properties(), NET::WM2ExtendedStrut);
     strut = info2.extendedStrut();
     QCOMPARE(strut.bottom_end, 32);
     QCOMPARE(strut.bottom_start, 22);
diff --git a/autotests/kwindowsystemx11test.cpp b/autotests/kwindowsystemx11test.cpp
--- a/autotests/kwindowsystemx11test.cpp
+++ b/autotests/kwindowsystemx11test.cpp
@@ -146,7 +146,7 @@
     // KWin has arbitrary max number of 20 desktops, so don't fail the test if we use +1
     const int newNumber = oldNumber < 20 ? oldNumber + 1 : oldNumber - 1;
 
-    NETRootInfo info(QX11Info::connection(), NET::NumberOfDesktops, nullptr);
+    NETRootInfo info(QX11Info::connection(), NET::NumberOfDesktops, NET::Properties2());
     info.setNumberOfDesktops(newNumber);
 
     QVERIFY(spy.wait());
@@ -196,7 +196,7 @@
 
     QSignalSpy spy(KWindowSystem::self(), SIGNAL(showingDesktopChanged(bool)));
 
-    NETRootInfo info(QX11Info::connection(), nullptr, NET::WM2ShowingDesktop);
+    NETRootInfo info(QX11Info::connection(), NET::Properties(), NET::WM2ShowingDesktop);
     info.setShowingDesktop(!showingDesktop);
 
     QVERIFY(spy.wait());
@@ -344,7 +344,7 @@
     // now let's verify the info in KWindowInfo
     // we wait a little bit more as openbox is updating the visible name
     QTest::qWait(500);
-    KWindowInfo info(widget.winId(), NET::WMName | NET::WMVisibleName | NET::WMVisibleIconName | NET::WMIconName, nullptr);
+    KWindowInfo info(widget.winId(), NET::WMName | NET::WMVisibleName | NET::WMVisibleIconName | NET::WMIconName, NET::Properties2());
     QVERIFY(info.valid());
     const QString expectedName = QStringLiteral("bar");
     QCOMPARE(info.name(), expectedName);
diff --git a/autotests/netwininfotestwm.cpp b/autotests/netwininfotestwm.cpp
--- a/autotests/netwininfotestwm.cpp
+++ b/autotests/netwininfotestwm.cpp
@@ -264,7 +264,7 @@
     ATOM(_NET_WM_ALLOWED_ACTIONS)
     INFO
 
-    QCOMPARE(info.allowedActions(), NET::Actions(nullptr));
+    QCOMPARE(info.allowedActions(), NET::Actions());
     QFETCH(NET::Actions, actions);
     info.setAllowedActions(actions);
     QCOMPARE(info.allowedActions(), actions);
@@ -472,9 +472,9 @@
     ATOM(_NET_WM_STATE)
     INFO
 
-    QCOMPARE(info.state(), NET::States(nullptr));
+    QCOMPARE(info.state(), NET::States());
     QFETCH(NET::States, states);
-    info.setState(states, nullptr);
+    info.setState(states, NET::States());
     QCOMPARE(info.state(), states);
 
     // compare with the X property
diff --git a/src/kstartupinfo.cpp b/src/kstartupinfo.cpp
--- a/src/kstartupinfo.cpp
+++ b/src/kstartupinfo.cpp
@@ -964,11 +964,11 @@
     if (!QX11Info::isPlatformX11()) {
         return QByteArray();
     }
-    NETWinInfo info(QX11Info::connection(), w_P, QX11Info::appRootWindow(), nullptr, NET::WM2StartupId | NET::WM2GroupLeader);
+    NETWinInfo info(QX11Info::connection(), w_P, QX11Info::appRootWindow(), NET::Properties(), NET::WM2StartupId | NET::WM2GroupLeader);
     QByteArray ret = info.startupId();
     if (ret.isEmpty() && info.groupLeader() != XCB_WINDOW_NONE) {
         // retry with window group leader, as the spec says
-        NETWinInfo groupLeaderInfo(QX11Info::connection(), info.groupLeader(), QX11Info::appRootWindow(), nullptr, NET::WM2StartupId);
+        NETWinInfo groupLeaderInfo(QX11Info::connection(), info.groupLeader(), QX11Info::appRootWindow(), NET::Properties(), NET::Properties2());
         ret = groupLeaderInfo.startupId();
     }
     return ret;
@@ -987,7 +987,7 @@
     if (id_P.isNull()) {
         return;
     }
-    NETWinInfo info(QX11Info::connection(), w_P, QX11Info::appRootWindow(), nullptr, nullptr);
+    NETWinInfo info(QX11Info::connection(), w_P, QX11Info::appRootWindow(), NET::Properties(), NET::Properties2());
     info.setStartupId(id_P.constData());
 #else
     Q_UNUSED(w_P)
diff --git a/src/kwindowinfo.h b/src/kwindowinfo.h
--- a/src/kwindowinfo.h
+++ b/src/kwindowinfo.h
@@ -83,7 +83,7 @@
      * @param properties Bitmask of NET::Property
      * @param properties2 Bitmask of NET::Property2
      */
-    KWindowInfo(WId window, NET::Properties properties, NET::Properties2 properties2 = nullptr);
+    KWindowInfo(WId window, NET::Properties properties, NET::Properties2 properties2 = NET::Properties2());
     ~KWindowInfo();
     /**
      * Returns false if this window info is not valid.
diff --git a/src/kwindowinfo.cpp b/src/kwindowinfo.cpp
--- a/src/kwindowinfo.cpp
+++ b/src/kwindowinfo.cpp
@@ -112,7 +112,7 @@
 
 NET::States KWindowInfoPrivateDummy::state() const
 {
-    return nullptr;
+    return NET::States();
 }
 
 bool KWindowInfoPrivateDummy::isMinimized() const
diff --git a/src/kwindowsystem.h b/src/kwindowsystem.h
--- a/src/kwindowsystem.h
+++ b/src/kwindowsystem.h
@@ -99,7 +99,7 @@
      * @return the window information
      * @deprecated use KWindowInfo directly
      */
-    KWINDOWSYSTEM_DEPRECATED static KWindowInfo windowInfo(WId win, NET::Properties properties, NET::Properties2 properties2 = nullptr);
+    KWINDOWSYSTEM_DEPRECATED static KWindowInfo windowInfo(WId win, NET::Properties properties, NET::Properties2 properties2 = NET::Properties2());
 #endif
 
     /**
diff --git a/src/platforms/xcb/kwindowinfo.cpp b/src/platforms/xcb/kwindowinfo.cpp
--- a/src/platforms/xcb/kwindowinfo.cpp
+++ b/src/platforms/xcb/kwindowinfo.cpp
@@ -272,7 +272,7 @@
         if (m_info->passedProperties() & NET::WMState) {
             return m_info->state() & NET::Sticky;
         }
-        NETWinInfo info(QX11Info::connection(), win(), QX11Info::appRootWindow(), NET::WMState, nullptr);
+        NETWinInfo info(QX11Info::connection(), win(), QX11Info::appRootWindow(), NET::WMState, NET::Properties2());
         return info.state() & NET::Sticky;
     }
     return m_info->desktop() == NET::OnAllDesktops;
diff --git a/src/platforms/xcb/kwindowsystem.cpp b/src/platforms/xcb/kwindowsystem.cpp
--- a/src/platforms/xcb/kwindowsystem.cpp
+++ b/src/platforms/xcb/kwindowsystem.cpp
@@ -265,7 +265,7 @@
             emit s_q->showingDesktopChanged(showingDesktop());
         }
     } else if (windows.contains(eventWindow)) {
-        NETWinInfo ni(QX11Info::connection(), eventWindow, m_appRootWindow, nullptr, nullptr);
+        NETWinInfo ni(QX11Info::connection(), eventWindow, m_appRootWindow, NET::Properties(), NET::Properties2());
         NET::Properties dirtyProperties;
         NET::Properties2 dirtyProperties2;
         ni.event(ev, &dirtyProperties, &dirtyProperties2);
@@ -347,7 +347,7 @@
     bool emit_strutChanged = false;
 
     if (strutSignalConnected) {
-        NETWinInfo info(QX11Info::connection(), w, QX11Info::appRootWindow(), NET::WMStrut | NET::WMDesktop, nullptr);
+        NETWinInfo info(QX11Info::connection(), w, QX11Info::appRootWindow(), NET::WMStrut | NET::WMDesktop, NET::Properties2());
         NETStrut strut = info.strut();
         if (strut.left || strut.top || strut.right || strut.bottom) {
             strutWindows.append(StrutData(w, strut, info.desktop()));
@@ -370,7 +370,7 @@
 
     bool emit_strutChanged = removeStrutWindow(w);
     if (strutSignalConnected && possibleStrutWindows.contains(w)) {
-        NETWinInfo info(QX11Info::connection(), w, QX11Info::appRootWindow(), NET::WMStrut, nullptr);
+        NETWinInfo info(QX11Info::connection(), w, QX11Info::appRootWindow(), NET::WMStrut, NET::Properties2());
         NETStrut strut = info.strut();
         if (strut.left || strut.top || strut.right || strut.bottom) {
             emit_strutChanged = true;
@@ -562,15 +562,15 @@
     if (mapViewport()) {
         init(INFO_BASIC);
         NETEventFilter *const s_d = s_d_func();
-        NETRootInfo info(QX11Info::connection(), nullptr);
+        NETRootInfo info(QX11Info::connection(), NET::Properties());
         QPoint pos = desktopToViewport(desktop, true);
         NETPoint p;
         p.x = pos.x();
         p.y = pos.y();
         info.setDesktopViewport(s_d->currentDesktop(true), p);
         return;
     }
-    NETRootInfo info(QX11Info::connection(), nullptr);
+    NETRootInfo info(QX11Info::connection(), NET::Properties());
     info.setCurrentDesktop(desktop, true);
 }
 
@@ -584,7 +584,7 @@
         }
         return;
     }
-    NETWinInfo info(QX11Info::connection(), win, QX11Info::appRootWindow(), NET::WMDesktop, nullptr);
+    NETWinInfo info(QX11Info::connection(), win, QX11Info::appRootWindow(), NET::WMDesktop, NET::Properties2());
     if (b) {
         info.setDesktop(NETWinInfo::OnAllDesktops, true);
     } else if (info.desktop(true)  == NETWinInfo::OnAllDesktops) {
@@ -630,13 +630,13 @@
         s_d->moveResizeWindowRequest(win, flags, p.x(), p.y(), w, h);
         return;
     }
-    NETWinInfo info(QX11Info::connection(), win, QX11Info::appRootWindow(), NET::WMDesktop, nullptr);
+    NETWinInfo info(QX11Info::connection(), win, QX11Info::appRootWindow(), NET::WMDesktop, NET::Properties2());
     info.setDesktop(desktop, true);
 }
 
 void KWindowSystemPrivateX11::setOnActivities(WId win, const QStringList &activities)
 {
-    NETWinInfo info(QX11Info::connection(), win, QX11Info::appRootWindow(), nullptr, NET::WM2Activities);
+    NETWinInfo info(QX11Info::connection(), win, QX11Info::appRootWindow(), NET::Properties(), NET::WM2Activities);
     info.setActivities(activities.join(QLatin1Char(',')).toLatin1().constData());
 }
 
@@ -652,7 +652,7 @@
 
 void KWindowSystemPrivateX11::activateWindow(WId win, long time)
 {
-    NETRootInfo info(QX11Info::connection(), nullptr);
+    NETRootInfo info(QX11Info::connection(), NET::Properties());
     if (time == 0) {
         time = QX11Info::appUserTime();
     }
@@ -662,31 +662,31 @@
 
 void KWindowSystemPrivateX11::forceActiveWindow(WId win, long time)
 {
-    NETRootInfo info(QX11Info::connection(), nullptr);
+    NETRootInfo info(QX11Info::connection(), NET::Properties());
     if (time == 0) {
         time = QX11Info::appTime();
     }
     info.setActiveWindow(win, NET::FromTool, time, 0);
 }
 
 void KWindowSystemPrivateX11::demandAttention(WId win, bool set)
 {
-    NETWinInfo info(QX11Info::connection(), win, QX11Info::appRootWindow(), NET::WMState, nullptr);
-    info.setState(set ? NET::DemandsAttention : NET::States(nullptr), NET::DemandsAttention);
+    NETWinInfo info(QX11Info::connection(), win, QX11Info::appRootWindow(), NET::WMState, NET::Properties2());
+    info.setState(set ? NET::DemandsAttention : NET::States(), NET::DemandsAttention);
 }
 
 #ifndef KWINDOWSYSTEM_NO_DEPRECATED
 WId KWindowSystemPrivateX11::transientFor(WId win)
 {
-    KWindowInfo info(win, nullptr, NET::WM2TransientFor);
+    KWindowInfo info(win, NET::Properties(), NET::WM2TransientFor);
     return info.transientFor();
 }
 #endif
 
 #ifndef KWINDOWSYSTEM_NO_DEPRECATED
 WId KWindowSystemPrivateX11::groupLeader(WId win)
 {
-    KWindowInfo info(win, nullptr, NET::WM2GroupLeader);
+    KWindowInfo info(win, NET::Properties(), NET::WM2GroupLeader);
     return info.groupLeader();
 }
 #endif
@@ -785,7 +785,7 @@
     if (icon.isNull()) {
         return;
     }
-    NETWinInfo info(QX11Info::connection(), win, QX11Info::appRootWindow(), nullptr, nullptr);
+    NETWinInfo info(QX11Info::connection(), win, QX11Info::appRootWindow(), NET::Properties(), NET::Properties2());
     QImage img = icon.toImage().convertToFormat(QImage::Format_ARGB32);
     NETIcon ni;
     ni.size.width = img.size().width();
@@ -807,20 +807,20 @@
 
 void KWindowSystemPrivateX11::setType(WId win, NET::WindowType windowType)
 {
-    NETWinInfo info(QX11Info::connection(), win, QX11Info::appRootWindow(), nullptr, nullptr);
+    NETWinInfo info(QX11Info::connection(), win, QX11Info::appRootWindow(), NET::Properties(), NET::Properties2());
     info.setWindowType(windowType);
 }
 
 void KWindowSystemPrivateX11::setState(WId win, NET::States state)
 {
-    NETWinInfo info(QX11Info::connection(), win, QX11Info::appRootWindow(), NET::WMState, nullptr);
+    NETWinInfo info(QX11Info::connection(), win, QX11Info::appRootWindow(), NET::WMState, NET::Properties2());
     info.setState(state, state);
 }
 
 void KWindowSystemPrivateX11::clearState(WId win, NET::States state)
 {
-    NETWinInfo info(QX11Info::connection(), win, QX11Info::appRootWindow(), NET::WMState, nullptr);
-    info.setState(nullptr, state);
+    NETWinInfo info(QX11Info::connection(), win, QX11Info::appRootWindow(), NET::WMState, NET::Properties2());
+    info.setState(NET::States(), state);
 }
 
 // enum values for ICCCM 4.1.2.4 and 4.1.4, defined to not depend on xcb-icccm
@@ -941,7 +941,7 @@
             strut = (*it2).strut;
         } else if (s_d->possibleStrutWindows.contains(*it1)) {
 
-            NETWinInfo info(QX11Info::connection(), (*it1), QX11Info::appRootWindow(), NET::WMStrut | NET::WMDesktop, nullptr);
+            NETWinInfo info(QX11Info::connection(), (*it1), QX11Info::appRootWindow(), NET::WMStrut | NET::WMDesktop, NET::Properties2());
             strut = info.strut();
             s_d->possibleStrutWindows.removeAll(*it1);
             s_d->strutWindows.append(NETEventFilter::StrutData(*it1, info.strut(), info.desktop()));
@@ -1000,7 +1000,7 @@
         return;
     }
 
-    NETRootInfo info(QX11Info::connection(), nullptr);
+    NETRootInfo info(QX11Info::connection(), NET::Properties());
     info.setDesktopName(desktop, name.toUtf8().constData());
 }
 
@@ -1012,21 +1012,21 @@
 
 void KWindowSystemPrivateX11::setShowingDesktop(bool showing)
 {
-    NETRootInfo info(QX11Info::connection(), nullptr, NET::WM2ShowingDesktop);
+    NETRootInfo info(QX11Info::connection(), NET::Properties(), NET::WM2ShowingDesktop);
     info.setShowingDesktop(showing);
 }
 
 void KWindowSystemPrivateX11::setUserTime(WId win, long time)
 {
-    NETWinInfo info(QX11Info::connection(), win, QX11Info::appRootWindow(), nullptr, nullptr);
+    NETWinInfo info(QX11Info::connection(), win, QX11Info::appRootWindow(), NET::Properties(), NET::Properties2());
     info.setUserTime(time);
 }
 
 void KWindowSystemPrivateX11::setExtendedStrut(WId win, int left_width, int left_start, int left_end,
                                      int right_width, int right_start, int right_end, int top_width, int top_start, int top_end,
                                      int bottom_width, int bottom_start, int bottom_end)
 {
-    NETWinInfo info(QX11Info::connection(), win, QX11Info::appRootWindow(), nullptr, nullptr);
+    NETWinInfo info(QX11Info::connection(), win, QX11Info::appRootWindow(), NET::Properties(), NET::Properties2());
     NETExtendedStrut strut;
     strut.left_width = left_width;
     strut.right_width = right_width;
@@ -1110,7 +1110,7 @@
 
 void KWindowSystemPrivateX11::setBlockingCompositing(WId window, bool active)
 {
-    NETWinInfo info(QX11Info::connection(), window, QX11Info::appRootWindow(), nullptr, nullptr);
+    NETWinInfo info(QX11Info::connection(), window, QX11Info::appRootWindow(), NET::Properties(), NET::Properties2());
     info.setBlockingCompositing(active);
 }
 
diff --git a/src/platforms/xcb/netwm.h b/src/platforms/xcb/netwm.h
--- a/src/platforms/xcb/netwm.h
+++ b/src/platforms/xcb/netwm.h
@@ -120,7 +120,7 @@
        @param doActivate true to call activate() to do an initial data read/update
        of the query information.
     **/
-    NETRootInfo(xcb_connection_t *connection, NET::Properties properties, NET::Properties2 properties2 = nullptr,
+    NETRootInfo(xcb_connection_t *connection, NET::Properties properties, NET::Properties2 properties2 = NET::Properties2(),
                 int screen = -1, bool doActivate = true);
 
 
@@ -1654,7 +1654,7 @@
     }
 
 private:
-    void update(NET::Properties dirtyProperties, NET::Properties2 dirtyProperties2 = nullptr);
+    void update(NET::Properties dirtyProperties, NET::Properties2 dirtyProperties2 = NET::Properties2());
     void updateWMState();
     void setIconInternal(NETRArray<NETIcon> &icons, int &icon_count, xcb_atom_t property, NETIcon icon, bool replace);
     NETIcon iconInternal(NETRArray<NETIcon> &icons, int icon_count, int width, int height) const;
diff --git a/src/platforms/xcb/netwm.cpp b/src/platforms/xcb/netwm.cpp
--- a/src/platforms/xcb/netwm.cpp
+++ b/src/platforms/xcb/netwm.cpp
@@ -549,11 +549,11 @@
     setDefaultProperties();
     p->clientProperties = properties;
     p->clientProperties2 = properties2;
-    p->properties = nullptr;
-    p->properties2 = nullptr;
-    p->windowTypes = nullptr;
-    p->states = nullptr;
-    p->actions = nullptr;
+    p->properties = NET::Properties();
+    p->properties2 = NET::Properties2();
+    p->windowTypes = NET::WindowTypes();
+    p->states = NET::States();
+    p->actions = NET::Actions();
 
     p->role = Client;
 
@@ -596,10 +596,10 @@
                                     | ToolbarMask | MenuMask | DialogMask;
     p->states = Modal | Sticky | MaxVert | MaxHoriz | Shaded
                               | SkipTaskbar | StaysOnTop;
-    p->properties2 = nullptr;
-    p->actions = nullptr;
-    p->clientProperties = nullptr;
-    p->clientProperties2 = nullptr;
+    p->properties2 = NET::Properties2();
+    p->actions = NET::Actions();
+    p->clientProperties = NET::Properties();
+    p->clientProperties2 = NET::Properties2();
 }
 
 void NETRootInfo::activate()
@@ -1973,11 +1973,11 @@
 
     if (dirty & Supported) {
         // Only in Client mode
-        p->properties = nullptr;
-        p->properties2 = nullptr;
-        p->windowTypes = nullptr;
-        p->states = nullptr;
-        p->actions = nullptr;
+        p->properties = NET::Properties();
+        p->properties2 = NET::Properties2();
+        p->windowTypes = NET::WindowTypes();
+        p->states = NET::States();
+        p->actions = NET::Actions();
 
         const QVector<xcb_atom_t> atoms = get_array_reply<xcb_atom_t>(p->conn, cookies[c++], XCB_ATOM_ATOM);
         Q_FOREACH (const xcb_atom_t atom, atoms) {
@@ -2325,21 +2325,21 @@
 {
     return p->role == WindowManager
            ? p->states
-           : NET::States(nullptr);
+           : NET::States();
 }
 
 NET::WindowTypes NETRootInfo::passedWindowTypes() const
 {
     return p->role == WindowManager
            ? p->windowTypes
-           : NET::WindowTypes(nullptr);
+           : NET::WindowTypes();
 }
 
 NET::Actions NETRootInfo::passedActions() const
 {
     return p->role == WindowManager
            ? p->actions
-           : NET::Actions(nullptr);
+           : NET::Actions();
 }
 
 void NETRootInfo::setSupported(NET::Property property, bool on)
@@ -2565,7 +2565,7 @@
     p->root = rootWindow;
     p->mapping_state = Withdrawn;
     p->mapping_state_dirty = true;
-    p->state = nullptr;
+    p->state = NET::States();
     p->types[ 0 ] = Unknown;
     p->name = (char *) nullptr;
     p->visible_name = (char *) nullptr;
@@ -2580,7 +2580,7 @@
     p->window_group = XCB_NONE;
     p->icon_pixmap = XCB_PIXMAP_NONE;
     p->icon_mask = XCB_PIXMAP_NONE;
-    p->allowed_actions = nullptr;
+    p->allowed_actions = NET::Actions();
     p->has_net_support = false;
     p->class_class = (char *) nullptr;
     p->class_name = (char *) nullptr;
@@ -2628,7 +2628,7 @@
     p->root = rootWindow;
     p->mapping_state = Withdrawn;
     p->mapping_state_dirty = true;
-    p->state = nullptr;
+    p->state = NET::States();
     p->types[ 0 ] = Unknown;
     p->name = (char *) nullptr;
     p->visible_name = (char *) nullptr;
@@ -2643,7 +2643,7 @@
     p->window_group = XCB_NONE;
     p->icon_pixmap = XCB_PIXMAP_NONE;
     p->icon_mask = XCB_PIXMAP_NONE;
-    p->allowed_actions = nullptr;
+    p->allowed_actions = NET::Actions();
     p->has_net_support = false;
     p->class_class = (char *) nullptr;
     p->class_name = (char *) nullptr;
@@ -2663,7 +2663,7 @@
     // p->frame_strut.bottom = 0;
 
     p->properties = properties;
-    p->properties2 = nullptr;
+    p->properties2 = NET::Properties2();
 
     p->icon_count = 0;
 
@@ -3607,7 +3607,7 @@
 #endif
 
             int i;
-            NET::States state = nullptr, mask = nullptr;
+            NET::States state = NET::States(), mask = NET::States();
 
             for (i = 1; i < 3; i++) {
 #ifdef NETWMDEBUG
@@ -3999,7 +3999,7 @@
     }
 
     if (dirty & WMState) {
-        p->state = nullptr;
+        p->state = NET::States();
         const QVector<xcb_atom_t> states = get_array_reply<xcb_atom_t>(p->conn, cookies[c++], XCB_ATOM_ATOM);
 
 #ifdef NETWMDEBUG
@@ -4354,7 +4354,7 @@
     }
 
     if (dirty2 & WM2AllowedActions) {
-        p->allowed_actions = nullptr;
+        p->allowed_actions = NET::Actions();
 
         const QVector<xcb_atom_t> actions = get_array_reply<xcb_atom_t>(p->conn, cookies[c++], XCB_ATOM_ATOM);
         if (actions.count() > 0) {