diff --git a/sources/main.cpp b/sources/main.cpp
index 8e3a05d36..cab5702ab 100644
--- a/sources/main.cpp
+++ b/sources/main.cpp
@@ -164,6 +164,14 @@ void delete_old_log_files(int days)
 */
 int main(int argc, char **argv)
 {
+	// before creating Application:
+	// export environment-variable "QT_HASH_SEED" with value "1" for Qt5 and "0" for Qt6
+	// to have "clean" XML-diffs:
+#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)	// ### Qt 6: remove
+	qputenv("QT_HASH_SEED", "1");
+#else
+	qputenv("QT_HASH_SEED", "0");
+#endif
 	//Some setup, notably to use with QSetting.
 	QCoreApplication::setOrganizationName("QElectroTech");
 	QCoreApplication::setOrganizationDomain("qelectrotech.org");