diff --git a/GraphicsView/include/CGAL/Qt/Basic_viewer_qt.h b/GraphicsView/include/CGAL/Qt/Basic_viewer_qt.h
index 2799c1c5790..944aa973fcf 100644
--- a/GraphicsView/include/CGAL/Qt/Basic_viewer_qt.h
+++ b/GraphicsView/include/CGAL/Qt/Basic_viewer_qt.h
@@ -141,6 +141,89 @@ const char fragment_source_p_l[] =
     "} \n"
     "\n"
   };
+
+//------------------------------------------------------------------------------
+//  compatibility shaders
+
+const char vertex_source_color_comp[] =
+  {
+    "attribute highp vec4 vertex;\n"
+    "attribute highp vec3 normal;\n"
+    "attribute highp vec3 color;\n"
+    
+    "uniform highp mat4 mvp_matrix;\n"
+    "uniform highp mat4 mv_matrix; \n"
+    
+    "varying highp vec4 fP; \n"
+    "varying highp vec3 fN; \n"
+    "varying highp vec4 fColor; \n"
+    
+    "uniform highp float point_size; \n"
+    "void main(void)\n"
+    "{\n"
+    "   fP = mv_matrix * vertex; \n"
+    "   fN = mat3(mv_matrix)* normal; \n"
+    "   fColor = vec4(color, 1.0); \n"
+    "   gl_PointSize = point_size;\n"
+    "   gl_Position = mvp_matrix * vertex;\n"
+    "}"
+  };
+
+const char fragment_source_color_comp[] =
+  {
+    "varying highp vec4 fP; \n"
+    "varying highp vec3 fN; \n"
+    "varying highp vec4 fColor; \n"
+    "uniform vec4 light_pos;  \n"
+    "uniform vec4 light_diff; \n"
+    "uniform vec4 light_spec; \n"
+    "uniform vec4 light_amb;  \n"
+    "uniform float spec_power ; \n"
+    
+    "void main(void) { \n"
+    
+    "   vec3 L = light_pos.xyz - fP.xyz; \n"
+    "   vec3 V = -fP.xyz; \n"
+    
+    "   vec3 N = normalize(fN); \n"
+    "   L = normalize(L); \n"
+    "   V = normalize(V); \n"
+    
+    "   vec3 R = reflect(-L, N); \n"
+    "   vec4 diffuse = max(dot(N,L), 0.0) * light_diff * fColor; \n"
+    "   vec4 specular = pow(max(dot(R,V), 0.0), spec_power) * light_spec; \n"
+    
+    "gl_FragColor = light_amb*fColor + diffuse  ; \n"
+    "} \n"
+    "\n"
+  };
+
+const char vertex_source_p_l_comp[] =
+  {
+    "attribute highp vec4 vertex;\n"
+    "attribute highp vec3 color;\n"
+    "uniform highp mat4 mvp_matrix;\n"
+    "varying highp vec4 fColor; \n"
+    "uniform highp float point_size; \n"
+    "void main(void)\n"
+    "{\n"
+    "   gl_PointSize = point_size;\n"
+    "   fColor = vec4(color, 1.0); \n"
+    "   gl_Position = mvp_matrix * vertex;\n"
+    "}"
+  };
+
+const char fragment_source_p_l_comp[] =
+  {
+    "varying highp vec4 fColor; \n"
+    "void main(void) { \n"
+    "gl_FragColor = fColor; \n"
+    "} \n"
+    "\n"
+  };
+
+
+
 //------------------------------------------------------------------------------
 inline CGAL::Color get_random_color(CGAL::Random& random)
 {
@@ -344,12 +427,21 @@ protected:
     }
     
     // Vertices and segments shader
+    
+    const char* source_ = isOpenGL_4_3() 
+        ? vertex_source_p_l
+        : vertex_source_p_l_comp;
+    
     QOpenGLShader *vertex_shader_p_l = new QOpenGLShader(QOpenGLShader::Vertex);
-    if(!vertex_shader_p_l->compileSourceCode(vertex_source_p_l))
+    if(!vertex_shader_p_l->compileSourceCode(source_))
     { std::cerr<<"Compiling vertex source FAILED"<<std::endl; }
 
+    source_ = isOpenGL_4_3() 
+        ? fragment_source_p_l
+        : fragment_source_p_l_comp;
+    
     QOpenGLShader *fragment_shader_p_l= new QOpenGLShader(QOpenGLShader::Fragment);
-    if(!fragment_shader_p_l->compileSourceCode(fragment_source_p_l))
+    if(!fragment_shader_p_l->compileSourceCode(source_))
     { std::cerr<<"Compiling fragmentsource FAILED"<<std::endl; }
 
     if(!rendering_program_p_l.addShader(vertex_shader_p_l))
@@ -360,10 +452,19 @@ protected:
     { std::cerr<<"linking Program FAILED"<<std::endl; }
 
     // Faces shader
+    
+    source_ = isOpenGL_4_3() 
+            ? vertex_source_color
+            : vertex_source_color_comp;
+    
     QOpenGLShader *vertex_shader_face = new QOpenGLShader(QOpenGLShader::Vertex);
-    if(!vertex_shader_face->compileSourceCode(vertex_source_color))
+    if(!vertex_shader_face->compileSourceCode(source_))
     { std::cerr<<"Compiling vertex source FAILED"<<std::endl; }
 
+    source_ = isOpenGL_4_3() 
+            ? fragment_source_color
+            : fragment_source_color_comp;
+    
     QOpenGLShader *fragment_shader_face= new QOpenGLShader(QOpenGLShader::Fragment);
     if(!fragment_shader_face->compileSourceCode(fragment_source_color))
     { std::cerr<<"Compiling fragmentsource FAILED"<<std::endl; }
diff --git a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/heat_intensity_shader.frag b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/heat_intensity_shader.frag
index fc327feaca6..7c18c72c70b 100644
--- a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/heat_intensity_shader.frag
+++ b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/heat_intensity_shader.frag
@@ -1,4 +1,4 @@
-#version 120
+
 varying highp vec4 color;
 varying highp float out_dist;
 void main(void) {
diff --git a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/heat_intensity_shader.vert b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/heat_intensity_shader.vert
index 732caf2c58c..c8f65a827cc 100644
--- a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/heat_intensity_shader.vert
+++ b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/heat_intensity_shader.vert
@@ -1,4 +1,4 @@
-#version 120
+
 attribute highp vec4 vertex;
 attribute highp vec3 normals;
 attribute highp vec3 colors;
diff --git a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_c3t3.frag b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_c3t3.frag
index f3da3d3d0e9..ea611daa7cf 100644
--- a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_c3t3.frag
+++ b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_c3t3.frag
@@ -1,4 +1,4 @@
-#version 120
+
 varying highp vec4 color;
 varying highp vec4 fP; 
 varying highp vec3 fN; 
diff --git a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_c3t3_edges.frag b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_c3t3_edges.frag
index 40c1e0e34ff..24fa8d08dc5 100644
--- a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_c3t3_edges.frag
+++ b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_c3t3_edges.frag
@@ -1,4 +1,4 @@
-#version 120
+
 varying highp vec4 color;
 void main(void) 
 { 
diff --git a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_no_light_no_selection.frag b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_no_light_no_selection.frag
index 22a7bc8aaa5..42960e7be03 100644
--- a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_no_light_no_selection.frag
+++ b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_no_light_no_selection.frag
@@ -1,4 +1,4 @@
-#version 120
+
 varying highp vec4 color;
 varying highp float dist[6];
 uniform bool is_clipbox_on;
diff --git a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_old_flat.frag b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_old_flat.frag
index 3326e4225af..559f01a9686 100644
--- a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_old_flat.frag
+++ b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_old_flat.frag
@@ -1,4 +1,4 @@
-#version 120
+
 varying highp vec4 color;
 varying highp vec4 fP;
 uniform highp vec4 light_pos;
diff --git a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_plane_two_faces.frag b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_plane_two_faces.frag
index 8c6a9a38251..8f2fc1837c4 100644
--- a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_plane_two_faces.frag
+++ b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_plane_two_faces.frag
@@ -1,4 +1,4 @@
-#version 120
+
 varying highp vec4 color;
 uniform highp vec3 dirView;
 uniform highp vec3 plane_normal;
diff --git a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_with_light.frag b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_with_light.frag
index 2d67a8e0223..d00eb11a9a2 100644
--- a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_with_light.frag
+++ b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_with_light.frag
@@ -1,4 +1,4 @@
-#version 120
+
 varying highp vec4 color;
 varying highp vec4 fP;
 varying highp vec3 fN;
diff --git a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_with_texture.frag b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_with_texture.frag
index 79034e2fcd6..8d398d7c6ef 100644
--- a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_with_texture.frag
+++ b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_with_texture.frag
@@ -1,4 +1,4 @@
-#version 120
+
 varying highp vec3 fColors;
 varying highp vec2 f_texCoord; 
 uniform sampler2D s_texture; 
diff --git a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_with_textured_edges.frag b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_with_textured_edges.frag
index eb35fed7437..3d006822334 100644
--- a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_with_textured_edges.frag
+++ b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_with_textured_edges.frag
@@ -1,4 +1,4 @@
-#version 120
+
 varying highp vec3 fColors;
 varying highp vec2 f_texCoord; 
 uniform highp sampler2D s_texture; 
diff --git a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_without_light.frag b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_without_light.frag
index 37a2143398c..57a1c4661a1 100644
--- a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_without_light.frag
+++ b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_without_light.frag
@@ -1,4 +1,4 @@
-#version 120
+
 varying highp vec4 color;
 varying highp float dist[6];
 uniform bool is_selected;