diff --git a/src/plugins/styles/gtk2/qgtkstyle.cpp b/src/plugins/styles/gtk2/qgtkstyle.cpp
index 36169c9..6138bd2 100644
--- a/src/plugins/styles/gtk2/qgtkstyle.cpp
+++ b/src/plugins/styles/gtk2/qgtkstyle.cpp
@@ -440,7 +440,11 @@ void QGtkStyle::polish(QApplication *app)
     // not supported as these should be entirely determined by
     // current Gtk settings
     if (app->desktopSettingsAware() && d->isThemeAvailable()) {
+#if QT_VERSION < QT_VERSION_CHECK(5, 15, 0)
         QApplicationPrivate::setSystemPalette(standardPalette());
+#else
+        QApplication::setPalette(standardPalette());
+#endif
         QApplicationPrivate::setSystemFont(d->getThemeFont());
         d->applyCustomPaletteHash();
         if (!d->isKDE4Session())
diff --git a/src/plugins/styles/gtk2/qgtkstyle_p.cpp b/src/plugins/styles/gtk2/qgtkstyle_p.cpp
index e57b3d8..e71beb0 100644
--- a/src/plugins/styles/gtk2/qgtkstyle_p.cpp
+++ b/src/plugins/styles/gtk2/qgtkstyle_p.cpp
@@ -508,7 +508,9 @@ void QGtkStyleUpdateScheduler::updateTheme()
       if (oldTheme != QGtkStylePrivate::getThemeName()) {
           oldTheme = QGtkStylePrivate::getThemeName();
           QPalette newPalette = qApp->style()->standardPalette();
+#if QT_VERSION < QT_VERSION_CHECK(5, 15, 0)
           QApplicationPrivate::setSystemPalette(newPalette);
+#endif
           QApplication::setPalette(newPalette);
           if (!QGtkStylePrivate::instances.isEmpty()) {
               QGtkStylePrivate::instances.last()->initGtkWidgets();