diff --git a/backends/kwayland/waylandoutput.cpp b/backends/kwayland/waylandoutput.cpp
--- a/backends/kwayland/waylandoutput.cpp
+++ b/backends/kwayland/waylandoutput.cpp
@@ -60,10 +60,12 @@
 
 QString WaylandOutput::toKScreenModeId(int kwaylandmodeid) const
 {
-    if (!m_modeIdMap.values().contains(kwaylandmodeid)) {
+    auto it = std::find(m_modeIdMap.cbegin(), m_modeIdMap.cend(), kwaylandmodeid);
+    if (it == m_modeIdMap.cend()) {
         qCWarning(KSCREEN_WAYLAND) << "Invalid kwayland mode id:" << kwaylandmodeid << m_modeIdMap;
+        return QStringLiteral("invalid_mode_id");
     }
-    return m_modeIdMap.key(kwaylandmodeid, QStringLiteral("invalid_mode_id"));
+    return it.key();
 }
 
 int WaylandOutput::toKWaylandModeId(const QString &kscreenmodeid) const
@@ -143,7 +145,7 @@
             qCDebug(KSCREEN_WAYLAND) << "Could not create mode id from" << m.id << ", using" << modename << "instead.";
             modeid = modename;
         }
-        if (m_modeIdMap.keys().contains(modeid)) {
+        if (m_modeIdMap.contains(modeid)) {
             qCWarning(KSCREEN_WAYLAND) << "Mode id already in use:" << modeid;
         }
 
diff --git a/backends/qscreen/qscreenconfig.cpp b/backends/qscreen/qscreenconfig.cpp
--- a/backends/qscreen/qscreenconfig.cpp
+++ b/backends/qscreen/qscreenconfig.cpp
@@ -44,7 +44,7 @@
 
 QScreenConfig::~QScreenConfig()
 {
-    foreach(auto output, m_outputMap.values()) {
+    foreach(auto output, m_outputMap) {
         delete output;
     }
 }
@@ -60,7 +60,7 @@
 int QScreenConfig::outputId(const QScreen *qscreen)
 {
     QList<int> ids;
-    foreach(auto output, m_outputMap.values()) {
+    foreach(auto output, m_outputMap) {
         if (qscreen == output->qscreen()) {
             return output->id();
         }
@@ -86,7 +86,7 @@
     qCDebug(KSCREEN_QSCREEN) << "Screen removed" << qscreen << QGuiApplication::screens().count();
     // Find output matching the QScreen object and remove it
     int removedOutputId = -1;
-    foreach(auto output, m_outputMap.values()) {
+    foreach(auto output, m_outputMap) {
         if (output->qscreen() == qscreen) {
             removedOutputId = output->id();
             m_outputMap.remove(removedOutputId);
@@ -105,14 +105,14 @@
     //Removing removed outputs
     KScreen::OutputList outputs = config->outputs();
     Q_FOREACH(const KScreen::OutputPtr &output, outputs) {
-        if (!m_outputMap.keys().contains(output->id())) {
+        if (!m_outputMap.contains(output->id())) {
             config->removeOutput(output->id());
         }
     }
 
     // Add KScreen::Outputs that aren't in the list yet, handle primaryOutput
     KScreen::OutputList kscreenOutputs = config->outputs();
-    foreach(QScreenOutput *output, m_outputMap.values()) {
+    foreach(QScreenOutput *output, m_outputMap) {
         KScreen::OutputPtr kscreenOutput = kscreenOutputs[output->id()];
 
         if (!kscreenOutput) {
diff --git a/src/output.cpp b/src/output.cpp
--- a/src/output.cpp
+++ b/src/output.cpp
@@ -98,12 +98,17 @@
 
 bool Output::Private::compareModeList(const ModeList& before, const ModeList &after)
 {
-    if (before.keys() != after.keys()) {
+    if (before.size() != after.size()) {
         return false;
     }
-    for (const QString &key : before.keys()) {
-        const auto mb = before.value(key);
-        const auto ma = after.value(key);
+
+    for (auto itb = before.cbegin(); itb != before.cend(); ++itb) {
+        auto ita = after.constFind(itb.key());
+        if (ita == after.cend()) {
+            return false;
+        }
+        const auto &mb = itb.value();
+        const auto &ma = ita.value();
         if (mb->id() != ma->id()) {
             return false;
         }
diff --git a/tests/kwayland/waylandconfigreader.cpp b/tests/kwayland/waylandconfigreader.cpp
--- a/tests/kwayland/waylandconfigreader.cpp
+++ b/tests/kwayland/waylandconfigreader.cpp
@@ -113,7 +113,7 @@
         OutputDeviceInterface::Mode m0;
         const QSize _size = sizeFromJson(mode[QStringLiteral("size")]);
 
-        if (mode.keys().contains(QStringLiteral("refreshRate"))) {
+        if (mode.contains(QStringLiteral("refreshRate"))) {
             m0.refreshRate = qRound(mode[QStringLiteral("refreshRate")].toReal() * 1000); // config has it in Hz
         }
         bool isCurrent = currentModeId == mode[QStringLiteral("id")].toInt();
@@ -128,7 +128,7 @@
             flags = OutputDeviceInterface::ModeFlags(OutputDeviceInterface::ModeFlag::Preferred);
         }
 
-        if (mode.keys().contains(QLatin1String("id"))) {
+        if (mode.contains(QLatin1String("id"))) {
             m0.id = mode[QStringLiteral("id")].toInt();
         } else {
             m0.id = mode_id;
diff --git a/tests/kwayland/waylandtestserver.cpp b/tests/kwayland/waylandtestserver.cpp
--- a/tests/kwayland/waylandtestserver.cpp
+++ b/tests/kwayland/waylandtestserver.cpp
@@ -126,8 +126,9 @@
     Q_EMIT configReceived();
 
     auto changes = configurationInterface->changes();
-    Q_FOREACH (const auto &outputdevice, changes.keys()) {
-        auto c = changes[outputdevice];
+    for (auto it = changes.cbegin(); it != changes.cend(); ++it) {
+        auto outputdevice = it.key();
+        auto c = it.value();
         if (c->enabledChanged()) {
             qCDebug(KSCREEN_WAYLAND_TESTSERVER) << "Setting enabled:";
             outputdevice->setEnabled(c->enabled());