diff --git a/src/hyperiond/main.cpp b/src/hyperiond/main.cpp
index 5d9457a6..f37cf34d 100644
--- a/src/hyperiond/main.cpp
+++ b/src/hyperiond/main.cpp
@@ -105,8 +105,8 @@ QCoreApplication* createApplication(int &argc, char *argv[])
 	{
 		// if x11, then test if xserver is available
 		#if defined(ENABLE_X11)
-		Display* dpy = XOpenDisplay(nullptr);
-		if (dpy != nullptr)
+		Display* dpy = XOpenDisplay(NULL);
+		if (dpy != NULL)
 		{
 			XCloseDisplay(dpy);
 			isGuiApp = true;
@@ -164,7 +164,7 @@ int main(int argc, char** argv)
 	// Initialising QCoreApplication
 	QScopedPointer<QCoreApplication> app(createApplication(argc, argv));
 
-	bool isGuiApp = (qobject_cast<QApplication *>(app.data()) != nullptr && QSystemTrayIcon::isSystemTrayAvailable());
+	bool isGuiApp = !(qobject_cast<QApplication *>(app.data()) == nullptr) && QSystemTrayIcon::isSystemTrayAvailable();
 
 	DefaultSignalHandler::install();