diff --git a/AABB_tree/demo/AABB_tree/AABB_demo.cpp b/AABB_tree/demo/AABB_tree/AABB_demo.cpp
index 9727327004f..881fd8710db 100644
--- a/AABB_tree/demo/AABB_tree/AABB_demo.cpp
+++ b/AABB_tree/demo/AABB_tree/AABB_demo.cpp
@@ -30,7 +30,7 @@ int main(int argc, char **argv)
   app.setOrganizationName("INRIA");
   app.setApplicationName("AABB tree demo");
 
-  // Import resources from libCGALQt (Qt5).
+  // Import resources from libCGALQt (Qt6).
   CGAL_QT_INIT_RESOURCES;
 
   MainWindow mainWindow;
diff --git a/Alpha_shapes_3/demo/Alpha_shapes_3/Alpha_shape_3.cpp b/Alpha_shapes_3/demo/Alpha_shapes_3/Alpha_shape_3.cpp
index 784ee1af57f..3ec08a1113e 100644
--- a/Alpha_shapes_3/demo/Alpha_shapes_3/Alpha_shape_3.cpp
+++ b/Alpha_shapes_3/demo/Alpha_shapes_3/Alpha_shape_3.cpp
@@ -16,8 +16,8 @@ int main(int argc, char** argv)
   application.setOrganizationName("GeometryFactory");
   application.setApplicationName("Alpha Shape Reconstruction");
 
-  // Import resources from libCGALQt (Qt5).
-  // See https://doc.qt.io/qt-5/qdir.html#Q_INIT_RESOURCE
+  // Import resources from libCGAL_Qt6
+  // See https://doc.qt.io/qt-6/qtresource-proxy.html#Q_INIT_RESOURCE
 
   CGAL_QT_INIT_RESOURCES;
   Q_INIT_RESOURCE(Alpha_shape_3);
diff --git a/Arrangement_on_surface_2/demo/Arrangement_on_surface_2/arrangement_2.cpp b/Arrangement_on_surface_2/demo/Arrangement_on_surface_2/arrangement_2.cpp
index 35d589585d8..f0a5ccfe47f 100644
--- a/Arrangement_on_surface_2/demo/Arrangement_on_surface_2/arrangement_2.cpp
+++ b/Arrangement_on_surface_2/demo/Arrangement_on_surface_2/arrangement_2.cpp
@@ -19,7 +19,7 @@ int main(int argc, char* argv[])
   QCoreApplication::setOrganizationName("CGAL");
   QCoreApplication::setApplicationName("2D Arrangements Demo");
 
-  // Import resources from libCGAL (Qt5).
+  // Import resources from libCGAL (Qt6).
   CGAL_QT_INIT_RESOURCES;
 
   ArrangementDemoWindow demoWindow;
diff --git a/Documentation/doc/Documentation/Third_party.txt b/Documentation/doc/Documentation/Third_party.txt
index d55d10c2cbe..569599ae0fd 100644
--- a/Documentation/doc/Documentation/Third_party.txt
+++ b/Documentation/doc/Documentation/Third_party.txt
@@ -107,8 +107,8 @@ the location of third-party software during configuration.
 
 Qt is a cross-platform application and UI framework.
 
-The component libCGAL_Qt5 is essential to run the \cgal demos and basic viewers.
-It requires \qt5 installed on your system.
+The component libCGAL_Qt6 is essential to run the \cgal demos and basic viewers.
+It requires \qt6 installed on your system.
 In case \qt is not yet installed on your system, you can download
 it from <A HREF="https://www.qt-project.org/">`https://www.qt-project.org/`</A>.
 
diff --git a/Documentation/doc/Documentation/Usage.txt b/Documentation/doc/Documentation/Usage.txt
index 1c02423cf49..046f3d6da38 100644
--- a/Documentation/doc/Documentation/Usage.txt
+++ b/Documentation/doc/Documentation/Usage.txt
@@ -171,9 +171,9 @@ In order to link against Qt5, you need to run:
 
     brew link qt@5
 
-After that, you will have to specify the Qt5_DIR by hand to cmake, using something like
+After that, you will have to specify the Qt6_DIR by hand to cmake, using something like
 
-    -DQt5_DIR=/usr/local/opt/qt5/lib/cmake/Qt5
+    -DQt6_DIR=/usr/local/opt/qt6/lib/cmake/Qt6
 
 where `/usr/local/` is actually your current brew installation directory. Check this directory
 to be sure where the Qt5 is placed on your machine.
diff --git a/Documentation/doc/Documentation/advanced/Configuration_variables.txt b/Documentation/doc/Documentation/advanced/Configuration_variables.txt
index 8434b496014..7cedae4344a 100644
--- a/Documentation/doc/Documentation/advanced/Configuration_variables.txt
+++ b/Documentation/doc/Documentation/advanced/Configuration_variables.txt
@@ -27,7 +27,7 @@ configure and/or build. Their values can be ON or OFF.
 | `WITH_examples`     | OFF   |
 | `WITH_demos`        | OFF   |
 | `WITH_CGAL_Core`    | ON    |
-| `WITH_CGAL_Qt5`     | ON    |
+| `WITH_CGAL_Qt6`     | ON    |
 | `WITH_CGAL_ImageIO` | ON    |
 
 \subsection installation_flags Compiler and Linker Flags
@@ -181,7 +181,7 @@ Under Linux, the \gmpxx is also searched for, and you may specify the following
 \subsection installation_qt5 Qt5 Library
 
 You must set the cmake or environment variable `Qt5_DIR` to point to the path
-to the directory containing the file `Qt5Config.cmake` created by your \qt5 installation. If you are
+to the directory containing the file `Qt6Config.cmake` created by your \qt6 installation. If you are
 using the open source edition it should be `<path>/qt-everywhere-opensource-src-<version>/qtbase/lib/cmake/Qt5`.
 
 \subsection installation_leda LEDA Library
diff --git a/Documentation/doc/Documentation/advanced/Installation.txt b/Documentation/doc/Documentation/advanced/Installation.txt
index 933565ad78f..7bf4f0f9874 100644
--- a/Documentation/doc/Documentation/advanced/Installation.txt
+++ b/Documentation/doc/Documentation/advanced/Installation.txt
@@ -61,7 +61,7 @@ See the page
 | :-------- | :------------- | :------------ | :----------- |
 |   \cgal   | none           | Main library  | \gmp, \mpfr, \boost (headers) |
 | `CGAL_ImageIO` | `WITH_CGAL_ImageIO` | Utilities to read and write image files  | \zlib, \vtk (optional) |
-| `CGAL_Qt5`  | `WITH_CGAL_Qt5` | `QGraphicsView` support for \qt5-based demos | \qt5 |
+| `CGAL_Qt6`  | `WITH_CGAL_Qt6` | `QGraphicsView` support for \qt6-based demos | \qt6 |
 
 \subsection installation_examples CGAL Examples and Demos
 
diff --git a/Documentation/doc/Documentation/windows.txt b/Documentation/doc/Documentation/windows.txt
index d40059d76cd..8b467453007 100644
--- a/Documentation/doc/Documentation/windows.txt
+++ b/Documentation/doc/Documentation/windows.txt
@@ -114,7 +114,7 @@ not depend on `Qt`. However, one of the examples in the Triangulation_2 package
 for visualization purposes. If you already have `Qt` installed, you can simply fill in the requested
 CMake variables and paths. Otherwise, you can also install it using `vcpkg`:
 
-    C:\dev\vcpkg> .\vcpkg.exe install qt5
+    C:\dev\vcpkg> .\vcpkg.exe install qt6
 
 Remember to specify `--triplet` or the related environment variable in case you target 64-bit applications.
 
diff --git a/Documentation/doc/resources/1.8.13/BaseDoxyfile.in b/Documentation/doc/resources/1.8.13/BaseDoxyfile.in
index 7f347c1529c..137dd3e63d8 100644
--- a/Documentation/doc/resources/1.8.13/BaseDoxyfile.in
+++ b/Documentation/doc/resources/1.8.13/BaseDoxyfile.in
@@ -78,7 +78,7 @@ ALIASES                = "cgal=%CGAL" \
                          "gnu=GNU" \
                          "ms=MS" \
                          "qt=Qt" \
-                         "qt5=Qt5" \
+                         "qt6=Qt6" \
                          "eigen=Eigen" \
                          "opengr=OpenGR" \
                          "libpointmatcher=libpointmatcher" \
diff --git a/Documentation/doc/resources/1.9.6/BaseDoxyfile.in b/Documentation/doc/resources/1.9.6/BaseDoxyfile.in
index f5d4533ce70..3548e27a271 100644
--- a/Documentation/doc/resources/1.9.6/BaseDoxyfile.in
+++ b/Documentation/doc/resources/1.9.6/BaseDoxyfile.in
@@ -87,7 +87,7 @@ ALIASES                = "cgal=%CGAL" \
                          "gnu=GNU" \
                          "ms=MS" \
                          "qt=Qt" \
-                         "qt5=Qt5" \
+                         "qt6=Qt6" \
                          "eigen=Eigen" \
                          "opengr=OpenGR" \
                          "libpointmatcher=libpointmatcher" \
diff --git a/GraphicsView/demo/Alpha_shapes_2/Alpha_shapes_2.cpp b/GraphicsView/demo/Alpha_shapes_2/Alpha_shapes_2.cpp
index d81a7cb7c49..31222218e48 100644
--- a/GraphicsView/demo/Alpha_shapes_2/Alpha_shapes_2.cpp
+++ b/GraphicsView/demo/Alpha_shapes_2/Alpha_shapes_2.cpp
@@ -311,7 +311,7 @@ int main(int argc, char **argv)
   app.setOrganizationName("GeometryFactory");
   app.setApplicationName("Alpha_shape_2 demo");
 
-  // Import resources from libCGAL (Qt5).
+  // Import resources from libCGAL (Qt6).
   CGAL_QT_INIT_RESOURCES;
 
   MainWindow mainWindow;
diff --git a/GraphicsView/demo/Apollonius_graph_2/Apollonius_graph_2.cpp b/GraphicsView/demo/Apollonius_graph_2/Apollonius_graph_2.cpp
index 31c3c828d76..7d42f4bddf1 100644
--- a/GraphicsView/demo/Apollonius_graph_2/Apollonius_graph_2.cpp
+++ b/GraphicsView/demo/Apollonius_graph_2/Apollonius_graph_2.cpp
@@ -313,7 +313,7 @@ int main(int argc, char **argv)
   app.setOrganizationName("GeometryFactory");
   app.setApplicationName("Apollonius_graph_2 demo");
 
-  // Import resources from libCGAL (Qt5).
+  // Import resources from libCGAL (Qt6).
   // See https://doc.qt.io/qt-5/qdir.html#Q_INIT_RESOURCE
   CGAL_QT_INIT_RESOURCES;
   Q_INIT_RESOURCE(Apollonius_graph_2);
diff --git a/GraphicsView/demo/Bounding_volumes/Bounding_volumes.cpp b/GraphicsView/demo/Bounding_volumes/Bounding_volumes.cpp
index c224faf6e66..7b6071d93ab 100644
--- a/GraphicsView/demo/Bounding_volumes/Bounding_volumes.cpp
+++ b/GraphicsView/demo/Bounding_volumes/Bounding_volumes.cpp
@@ -573,7 +573,7 @@ int main(int argc, char **argv)
   app.setOrganizationName("GeometryFactory");
   app.setApplicationName("Bounding_volumes demo");
 
-  // Import resources from libCGAL (Qt5).
+  // Import resources from libCGAL (Qt6).
   // See https://doc.qt.io/qt-5/qdir.html#Q_INIT_RESOURCE
   CGAL_QT_INIT_RESOURCES;
 
diff --git a/GraphicsView/demo/Circular_kernel_2/Circular_kernel_2.cpp b/GraphicsView/demo/Circular_kernel_2/Circular_kernel_2.cpp
index e593af52c14..53555763d10 100644
--- a/GraphicsView/demo/Circular_kernel_2/Circular_kernel_2.cpp
+++ b/GraphicsView/demo/Circular_kernel_2/Circular_kernel_2.cpp
@@ -336,7 +336,7 @@ int main(int argc, char **argv)
   app.setOrganizationName("GeometryFactory");
   app.setApplicationName("Circular_kernel_2 demo");
 
-  // Import resources from libCGAL (Qt5).
+  // Import resources from libCGAL (Qt6).
   CGAL_QT_INIT_RESOURCES;
 
   MainWindow mainWindow;
diff --git a/GraphicsView/demo/Generator/Generator_2.cpp b/GraphicsView/demo/Generator/Generator_2.cpp
index 0072354e66c..a10c3566a10 100644
--- a/GraphicsView/demo/Generator/Generator_2.cpp
+++ b/GraphicsView/demo/Generator/Generator_2.cpp
@@ -338,7 +338,7 @@ int main(int argc, char **argv)
   app.setOrganizationName("GeometryFactory");
   app.setApplicationName("Generator_2 demo");
 
-  // Import resources from libCGAL (Qt5).
+  // Import resources from libCGAL (Qt6).
   // See https://doc.qt.io/qt-5/qdir.html#Q_INIT_RESOURCE
   CGAL_QT_INIT_RESOURCES;
   Q_INIT_RESOURCE(Generator_2);
diff --git a/GraphicsView/demo/L1_Voronoi_diagram_2/L1_voronoi_diagram_2.cpp b/GraphicsView/demo/L1_Voronoi_diagram_2/L1_voronoi_diagram_2.cpp
index 726a509b885..57aaab80f01 100644
--- a/GraphicsView/demo/L1_Voronoi_diagram_2/L1_voronoi_diagram_2.cpp
+++ b/GraphicsView/demo/L1_Voronoi_diagram_2/L1_voronoi_diagram_2.cpp
@@ -395,7 +395,7 @@ int main(int argc, char **argv)
   app.setOrganizationName("GeometryFactory");
   app.setApplicationName("L1 Voronoi diagram_2 demo");
 
-  // Import resources from libCGAL (Qt5).
+  // Import resources from libCGAL (Qt6).
   CGAL_QT_INIT_RESOURCES;
 
   MainWindow mainWindow;
diff --git a/GraphicsView/demo/Largest_empty_rect_2/Largest_empty_rectangle_2.cpp b/GraphicsView/demo/Largest_empty_rect_2/Largest_empty_rectangle_2.cpp
index 67e4f336075..20e13248017 100644
--- a/GraphicsView/demo/Largest_empty_rect_2/Largest_empty_rectangle_2.cpp
+++ b/GraphicsView/demo/Largest_empty_rect_2/Largest_empty_rectangle_2.cpp
@@ -327,7 +327,7 @@ int main(int argc, char **argv)
   app.setOrganizationName("GeometryFactory");
   app.setApplicationName("Largest_empty_rectangle_2 demo");
 
-  // Import resources from libCGAL (Qt5).
+  // Import resources from libCGAL (Qt6).
   // See https://doc.qt.io/qt-5/qdir.html#Q_INIT_RESOURCE
   CGAL_QT_INIT_RESOURCES;
   Q_INIT_RESOURCE(Largest_empty_rectangle_2);
diff --git a/GraphicsView/demo/Periodic_2_triangulation_2/Periodic_2_Delaunay_triangulation_2.cpp b/GraphicsView/demo/Periodic_2_triangulation_2/Periodic_2_Delaunay_triangulation_2.cpp
index 00beec2bc22..b878c6c69dd 100644
--- a/GraphicsView/demo/Periodic_2_triangulation_2/Periodic_2_Delaunay_triangulation_2.cpp
+++ b/GraphicsView/demo/Periodic_2_triangulation_2/Periodic_2_Delaunay_triangulation_2.cpp
@@ -476,7 +476,7 @@ int main(int argc, char **argv)
   app.setOrganizationName("Nico Kruithof");
   app.setApplicationName("Periodic_2_Delaunay_triangulation_2 demo");
 
-  // Import resources from libCGAL (Qt5).
+  // Import resources from libCGAL (Qt6).
   // See https://doc.qt.io/qt-5/qdir.html#Q_INIT_RESOURCE
   CGAL_QT_INIT_RESOURCES;
 
diff --git a/GraphicsView/demo/Polygon/Polygon_2.cpp b/GraphicsView/demo/Polygon/Polygon_2.cpp
index 67c16d0b3dc..dc9fdf66275 100644
--- a/GraphicsView/demo/Polygon/Polygon_2.cpp
+++ b/GraphicsView/demo/Polygon/Polygon_2.cpp
@@ -596,7 +596,7 @@ int main(int argc, char **argv)
   app.setOrganizationName("GeometryFactory");
   app.setApplicationName("Polygon_2 demo");
 
-  // Import resources from libCGAL (Qt5).
+  // Import resources from libCGAL (Qt6).
   // See https://doc.qt.io/qt-5/qdir.html#Q_INIT_RESOURCE
   CGAL_QT_INIT_RESOURCES;
   Q_INIT_RESOURCE(Polygon_2);
diff --git a/GraphicsView/demo/Segment_Delaunay_graph_2/Segment_voronoi_2.cpp b/GraphicsView/demo/Segment_Delaunay_graph_2/Segment_voronoi_2.cpp
index 07845c04bc3..de2e7b18cee 100644
--- a/GraphicsView/demo/Segment_Delaunay_graph_2/Segment_voronoi_2.cpp
+++ b/GraphicsView/demo/Segment_Delaunay_graph_2/Segment_voronoi_2.cpp
@@ -426,7 +426,7 @@ int main(int argc, char **argv)
   app.setOrganizationName("GeometryFactory");
   app.setApplicationName("Segment Voronoi 2 demo");
 
-  // Import resources from libCGAL (Qt5).
+  // Import resources from libCGAL (Qt6).
   CGAL_QT_INIT_RESOURCES;
 
   MainWindow mainWindow;
diff --git a/GraphicsView/demo/Snap_rounding_2/Snap_rounding_2.cpp b/GraphicsView/demo/Snap_rounding_2/Snap_rounding_2.cpp
index 8ab184cfdce..9af19ac62f1 100644
--- a/GraphicsView/demo/Snap_rounding_2/Snap_rounding_2.cpp
+++ b/GraphicsView/demo/Snap_rounding_2/Snap_rounding_2.cpp
@@ -341,7 +341,7 @@ int main(int argc, char **argv)
   app.setOrganizationName("GeometryFactory");
   app.setApplicationName("Snap_rounding_2 demo");
 
-  // Import resources from libCGAL (Qt5).
+  // Import resources from libCGAL (Qt6).
   // See https://doc.qt.io/qt-5/qdir.html#Q_INIT_RESOURCE
   CGAL_QT_INIT_RESOURCES;
   Q_INIT_RESOURCE(Snap_rounding_2);
diff --git a/GraphicsView/demo/Spatial_searching_2/Spatial_searching_2.cpp b/GraphicsView/demo/Spatial_searching_2/Spatial_searching_2.cpp
index d25a215c8cc..0c982df5ccb 100644
--- a/GraphicsView/demo/Spatial_searching_2/Spatial_searching_2.cpp
+++ b/GraphicsView/demo/Spatial_searching_2/Spatial_searching_2.cpp
@@ -302,7 +302,7 @@ int main(int argc, char **argv)
   app.setOrganizationName("GeometryFactory");
   app.setApplicationName("Spatial_searching_2 demo");
 
-  // Import resources from libCGAL (Qt5).
+  // Import resources from libCGAL (Qt6).
   // See https://doc.qt.io/qt-5/qdir.html#Q_INIT_RESOURCE
   CGAL_QT_INIT_RESOURCES;
   Q_INIT_RESOURCE(Spatial_searching_2);
diff --git a/GraphicsView/demo/Stream_lines_2/Stream_lines_2.cpp b/GraphicsView/demo/Stream_lines_2/Stream_lines_2.cpp
index 37e2138ece5..7dd2b13661b 100644
--- a/GraphicsView/demo/Stream_lines_2/Stream_lines_2.cpp
+++ b/GraphicsView/demo/Stream_lines_2/Stream_lines_2.cpp
@@ -279,7 +279,7 @@ int main(int argc, char **argv)
   app.setOrganizationName("GeometryFactory");
   app.setApplicationName("Stream_lines_2 demo");
 
-  // Import resources from libCGAL (Qt5).
+  // Import resources from libCGAL (Qt6).
   // See https://doc.qt.io/qt-5/qdir.html#Q_INIT_RESOURCE
   CGAL_QT_INIT_RESOURCES;
   Q_INIT_RESOURCE(Stream_lines_2);
diff --git a/GraphicsView/demo/Triangulation_2/Constrained_Delaunay_triangulation_2.cpp b/GraphicsView/demo/Triangulation_2/Constrained_Delaunay_triangulation_2.cpp
index 5da75ee41da..990a8952cad 100644
--- a/GraphicsView/demo/Triangulation_2/Constrained_Delaunay_triangulation_2.cpp
+++ b/GraphicsView/demo/Triangulation_2/Constrained_Delaunay_triangulation_2.cpp
@@ -923,7 +923,7 @@ int main(int argc, char **argv)
   app.setOrganizationName("GeometryFactory");
   app.setApplicationName("Constrained_Delaunay_triangulation_2 demo");
 
-  // Import resources from libCGAL (Qt5).
+  // Import resources from libCGAL (Qt6).
   CGAL_QT_INIT_RESOURCES;
 
   MainWindow mainWindow;
diff --git a/GraphicsView/demo/Triangulation_2/Delaunay_triangulation_2.cpp b/GraphicsView/demo/Triangulation_2/Delaunay_triangulation_2.cpp
index e00d9fa260f..55a11c0171b 100644
--- a/GraphicsView/demo/Triangulation_2/Delaunay_triangulation_2.cpp
+++ b/GraphicsView/demo/Triangulation_2/Delaunay_triangulation_2.cpp
@@ -412,7 +412,7 @@ int main(int argc, char **argv)
   app.setOrganizationName("GeometryFactory");
   app.setApplicationName("Delaunay_triangulation_2 demo");
 
-  // Import resources from libCGAL (QT5).
+  // Import resources from libCGAL (Qt6).
   CGAL_QT_INIT_RESOURCES;
 
   MainWindow mainWindow;
diff --git a/GraphicsView/demo/Triangulation_2/Regular_triangulation_2.cpp b/GraphicsView/demo/Triangulation_2/Regular_triangulation_2.cpp
index 6df0dd31901..07a3ed67ad0 100644
--- a/GraphicsView/demo/Triangulation_2/Regular_triangulation_2.cpp
+++ b/GraphicsView/demo/Triangulation_2/Regular_triangulation_2.cpp
@@ -334,7 +334,7 @@ int main(int argc, char **argv)
   app.setOrganizationName("GeometryFactory");
   app.setApplicationName("Regular_triangulation_2 demo");
 
-  // Import resources from libCGAL (Qt5).
+  // Import resources from libCGAL (Qt6).
   CGAL_QT_INIT_RESOURCES;
 
   MainWindow mainWindow;
diff --git a/Hyperbolic_triangulation_2/demo/Hyperbolic_triangulation_2/HDT2.cpp b/Hyperbolic_triangulation_2/demo/Hyperbolic_triangulation_2/HDT2.cpp
index bd76416342b..9dd9c45c7f9 100644
--- a/Hyperbolic_triangulation_2/demo/Hyperbolic_triangulation_2/HDT2.cpp
+++ b/Hyperbolic_triangulation_2/demo/Hyperbolic_triangulation_2/HDT2.cpp
@@ -411,7 +411,7 @@ int main(int argc, char **argv)
   app.setOrganizationName("GeometryFactory");
   app.setApplicationName("Hyperbolic_Delaunay_triangulation_2 demo");
 
-  // Import resources from libCGAL (QT5).
+  // Import resources from libCGAL (Qt6).
   CGAL_QT_INIT_RESOURCES;
 
   MainWindow mainWindow;
diff --git a/Periodic_3_triangulation_3/demo/Periodic_Lloyd_3/Periodic_Lloyd_3.cpp b/Periodic_3_triangulation_3/demo/Periodic_Lloyd_3/Periodic_Lloyd_3.cpp
index ae0074e0bcc..0f8f1dd27b9 100644
--- a/Periodic_3_triangulation_3/demo/Periodic_Lloyd_3/Periodic_Lloyd_3.cpp
+++ b/Periodic_3_triangulation_3/demo/Periodic_Lloyd_3/Periodic_Lloyd_3.cpp
@@ -13,7 +13,7 @@ int main(int argc, char** argv)
   application.setOrganizationName("INRIA");
   application.setApplicationName("3D Periodic Lloyd");
 
-  // Import resources from libCGAL (QT5).
+  // Import resources from libCGAL (Qt6).
   // See https://doc.qt.io/qt-5/qdir.html#Q_INIT_RESOURCE
   CGAL_QT_INIT_RESOURCES;
   Q_INIT_RESOURCE(Periodic_Lloyd_3);
diff --git a/Polyhedron/demo/Polyhedron/Polyhedron_demo.cpp b/Polyhedron/demo/Polyhedron/Polyhedron_demo.cpp
index 7b6e5225dfe..05f30fa3da6 100644
--- a/Polyhedron/demo/Polyhedron/Polyhedron_demo.cpp
+++ b/Polyhedron/demo/Polyhedron/Polyhedron_demo.cpp
@@ -54,7 +54,7 @@ Polyhedron_demo::Polyhedron_demo(int& argc, char **argv,
   std::cout.precision(17);
   std::clog.precision(17);
 
-  // Import resources from libCGAL (Qt5).
+  // Import resources from libCGAL (Qt6).
   CGAL_QT_INIT_RESOURCES;
 
   this->setOrganizationDomain("geometryfactory.com");