diff --git a/libkwineffects/kwinglplatform.cpp b/libkwineffects/kwinglplatform.cpp
--- a/libkwineffects/kwinglplatform.cpp
+++ b/libkwineffects/kwinglplatform.cpp
@@ -686,12 +686,8 @@
         }
     } else {
         const QByteArray extensions = (const char *) glGetString(GL_EXTENSIONS);
-#if (QT_VERSION >= QT_VERSION_CHECK(5, 14, 0))
-        const QList<QByteArray> extensionsList = extensions.split(' ');
+        QList<QByteArray> extensionsList = extensions.split(' ');
         m_extensions = {extensionsList.constBegin(), extensionsList.constEnd()};
-#else
-        m_extensions = extensions.split(' ').toSet();
-#endif
     }
 
     // Parse the Mesa version
diff --git a/plugins/platforms/drm/drm_backend.cpp b/plugins/platforms/drm/drm_backend.cpp
--- a/plugins/platforms/drm/drm_backend.cpp
+++ b/plugins/platforms/drm/drm_backend.cpp
@@ -803,16 +803,11 @@
     QString supportInfo;
     QDebug s(&supportInfo);
     s.nospace();
-
-#if (QT_VERSION >= QT_VERSION_CHECK(5, 14, 0))
-    using Qt::endl;
-#endif
-
-    s << "Name: " << "DRM" << endl;
-    s << "Active: " << m_active << endl;
-    s << "Atomic Mode Setting: " << m_atomicModeSetting << endl;
+    s << "Name: " << "DRM" << Qt::endl;
+    s << "Active: " << m_active << Qt::endl;
+    s << "Atomic Mode Setting: " << m_atomicModeSetting << Qt::endl;
 #if HAVE_EGL_STREAMS
-    s << "Using EGL Streams: " << m_useEglStreams << endl;
+    s << "Using EGL Streams: " << m_useEglStreams << Qt::endl;
 #endif
     return supportInfo;
 }
diff --git a/plugins/platforms/x11/standalone/glxbackend.cpp b/plugins/platforms/x11/standalone/glxbackend.cpp
--- a/plugins/platforms/x11/standalone/glxbackend.cpp
+++ b/plugins/platforms/x11/standalone/glxbackend.cpp
@@ -572,11 +572,8 @@
     const xcb_render_pictformat_t format = XRenderUtils::findPictFormat(visual);
     const xcb_render_directformat_t *direct = XRenderUtils::findPictFormatInfo(format);
 
-#if (QT_VERSION >= QT_VERSION_CHECK(5, 14, 0))
-        using Qt::hex;
-#endif
     if (!direct) {
-        qCCritical(KWIN_X11STANDALONE).nospace() << "Could not find a picture format for visual 0x" << hex << visual;
+        qCCritical(KWIN_X11STANDALONE).nospace() << "Could not find a picture format for visual 0x" << Qt::hex << visual;
         return info;
     }
 
@@ -610,7 +607,7 @@
     GLXFBConfig *configs = glXChooseFBConfig(display(), DefaultScreen(display()), attribs, &count);
 
     if (count < 1) {
-        qCCritical(KWIN_X11STANDALONE).nospace() << "Could not find a framebuffer configuration for visual 0x" << hex << visual;
+        qCCritical(KWIN_X11STANDALONE).nospace() << "Could not find a framebuffer configuration for visual 0x" << Qt::hex << visual;
         return info;
     }
 
@@ -692,7 +689,7 @@
         glXGetFBConfigAttrib(display(), info->fbconfig, GLX_FBCONFIG_ID, &fbc_id);
         glXGetFBConfigAttrib(display(), info->fbconfig, GLX_VISUAL_ID,   &visual_id);
 
-        qCDebug(KWIN_X11STANDALONE).nospace() << "Using FBConfig 0x" << hex << fbc_id << " for visual 0x" << hex << visual_id;
+        qCDebug(KWIN_X11STANDALONE).nospace() << "Using FBConfig 0x" << Qt::hex << fbc_id << " for visual 0x" << Qt::hex << visual_id;
     }
 
     return info;
diff --git a/wayland_server.cpp b/wayland_server.cpp
--- a/wayland_server.cpp
+++ b/wayland_server.cpp
@@ -763,11 +763,7 @@
 
 quint16 WaylandServer::createClientId(ClientConnection *c)
 {
-#if (QT_VERSION >= QT_VERSION_CHECK(5, 14, 0))
     const QSet<unsigned short> ids(m_clientIds.constBegin(), m_clientIds.constEnd());
-#else
-    const auto ids = m_clientIds.values().toSet();
-#endif
     quint16 id = 1;
     if (!ids.isEmpty()) {
         for (quint16 i = ids.count() + 1; i >= 1 ; i--) {