diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4345ea2..34dd413 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -127,7 +127,7 @@ ENDIF()
 
 PROJECT(osgQt)
 
-FIND_PACKAGE(OpenSceneGraph 3.5.6 REQUIRED osgDB osgGA osgUtil osgText osgViewer osgWidget)
+FIND_PACKAGE(OpenSceneGraph 3.0.0 REQUIRED osgDB osgGA osgUtil osgText osgViewer osgWidget)
 SET(OPENSCENEGRAPH_SOVERSION 145)
 
 SET(OSG_PLUGINS osgPlugins-${OPENSCENEGRAPH_VERSION})
diff --git a/include/osgQt/GraphicsWindowQt b/include/osgQt/GraphicsWindowQt
index 825676d..a538b34 100644
--- a/include/osgQt/GraphicsWindowQt
+++ b/include/osgQt/GraphicsWindowQt
@@ -22,6 +22,7 @@
 #include <QQueue>
 #include <QSet>
 #include <QGLWidget>
+#include <osg/Version>
 
 class QInputEvent;
 class QGestureEvent;
@@ -36,7 +37,7 @@ namespace osgQt
 // forward declarations
 class GraphicsWindowQt;
 
-#if 0
+#if OSG_VERSION_LESS_THAN(3, 5, 6)
 /// The function sets the WindowingSystem to Qt.
 void OSGQT_EXPORT initQtWindowingSystem();
 #endif
diff --git a/src/osgQt/GraphicsWindowQt.cpp b/src/osgQt/GraphicsWindowQt.cpp
index 2fd3855..a2ad092 100644
--- a/src/osgQt/GraphicsWindowQt.cpp
+++ b/src/osgQt/GraphicsWindowQt.cpp
@@ -945,7 +945,7 @@ class QtWindowingSystem : public osg::GraphicsContext::WindowingSystemInterface
     QtWindowingSystem& operator=( const QtWindowingSystem& );
 };
 
-#if 1
+#if OSG_VERSION_GREATER_OR_EQUAL(3, 5, 6)
 REGISTER_WINDOWINGSYSTEMINTERFACE(Qt, QtWindowingSystem)
 #else