IT's enabled by default in qt6

src/KBruch.cpp

@@ -31,7 +31,9 @@ int main(int argc, char * argv[])
 {
     // init random generator
     qsrand(time(nullptr));
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
     QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
+#endif
     QApplication app(argc, argv);
     app.setAttribute(Qt::AA_UseHighDpiPixmaps, true);