diff --git a/logqso.h b/logqso.h
index a7ea6b4fe..a4edbb00e 100644
--- a/logqso.h
+++ b/logqso.h
@@ -1,8 +1,11 @@
 #ifndef LogQSO_H
 #define LogQSO_H
 
+#ifdef QT5
+#include <QtWidgets>
+#else
 #include <QtGui>
-//#include <QDialog>
+#endif
 
 namespace Ui {
 class LogQSO;
diff --git a/main.cpp b/main.cpp
index fe90346fc..08bf7eb8c 100644
--- a/main.cpp
+++ b/main.cpp
@@ -1,4 +1,8 @@
+#ifdef QT5
+#include <QtWidgets>
+#else
 #include <QtGui>
+#endif
 #include <QApplication>
 #include <portaudio.h>
 #include "mainwindow.h"
diff --git a/mainwindow.cpp b/mainwindow.cpp
index d54c6a445..471655c59 100644
--- a/mainwindow.cpp
+++ b/mainwindow.cpp
@@ -9,8 +9,11 @@
 #include "getfile.h"
 #include <portaudio.h>
 #include "logqso.h"
-//#include <QtConcurrent/QtConcurrentMap>
-//#include <QtConcurrent/QtConcurrentRun>
+
+#ifdef QT5
+#include <QtConcurrent/QtConcurrentMap>
+#include <QtConcurrent/QtConcurrentRun>
+#endif
 
 int itone[85];                        //Tx audio tones for 85 symbols
 int icw[250];                         //Dits for CW ID
diff --git a/mainwindow.h b/mainwindow.h
index 913d80ded..0013721ba 100644
--- a/mainwindow.h
+++ b/mainwindow.h
@@ -1,6 +1,10 @@
 #ifndef MAINWINDOW_H
 #define MAINWINDOW_H
+#ifdef QT5
+#include <QtWidgets>
+#else
 #include <QtGui>
+#endif
 #include <QTimer>
 #include <QDateTime>
 #include "soundin.h"
diff --git a/plotter.h b/plotter.h
index 2e08d5b26..077853ea8 100644
--- a/plotter.h
+++ b/plotter.h
@@ -7,7 +7,11 @@
 #ifndef PLOTTER_H
 #define PLOTTER_H
 
+#ifdef QT5
+#include <QtWidgets>
+#else
 #include <QtGui>
+#endif
 #include <QFrame>
 #include <QImage>
 #include <cstring>
diff --git a/wsjtx.pro b/wsjtx.pro
index da247c94f..d3acc2779 100644
--- a/wsjtx.pro
+++ b/wsjtx.pro
@@ -14,9 +14,10 @@ DESTDIR = ../wsjtx_install
 #DESTDIR = ../qt5_install
 VERSION = 0.99
 TEMPLATE = app
+DEFINES = QT4
 
 win32 {
-DEFINES = WIN32
+DEFINES += WIN32
 F90 = g95
 g95.output = ${QMAKE_FILE_BASE}.o
 g95.commands = $$F90 -c -O2 -o ${QMAKE_FILE_OUT} ${QMAKE_FILE_NAME}
@@ -25,7 +26,7 @@ QMAKE_EXTRA_COMPILERS += g95
 }
 
 unix {
-DEFINES = UNIX
+DEFINES += UNIX
 F90 = gfortran
 gfortran.output = ${QMAKE_FILE_BASE}.o
 gfortran.commands = $$F90 -c -O2 -o ${QMAKE_FILE_OUT} ${QMAKE_FILE_NAME}