Remove Qt5 compatibility ifdefs

src/main.cpp

@@ -140,19 +140,13 @@ Q_DECL_EXPORT
 #endif
 int main(int argc, char *argv[])
 {
-#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
-    QGuiApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
-#endif
-
     QNetworkProxyFactory::setUseSystemConfiguration(true);
 
 #ifdef HAVE_WEBVIEW
     QtWebView::initialize();
     QCoreApplication::setAttribute(Qt::AA_ShareOpenGLContexts);
-#if QT_VERSION > QT_VERSION_CHECK(6, 0, 0)
     QQuickWindow::setGraphicsApi(QSGRendererInterface::OpenGLRhi);
 #endif
-#endif
 
 #ifdef Q_OS_ANDROID
     QGuiApplication app(argc, argv);
@@ -311,10 +305,6 @@ int main(int argc, char *argv[])
         return engine->toScriptValue(LocationHelper());
     });
 
-#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
-    qRegisterMetaTypeStreamOperators<Emoji>();
-#endif
-
     QQmlApplicationEngine engine;
 
 #ifdef HAVE_KDBUSADDONS