recommend occt 7.1

README.txt

@@ -13,8 +13,8 @@ http://gmsh.info for additional examples.
 Building Gmsh from its source code requires a C++ compiler and CMake
 (http://cmake.org). Building the graphical user interface requires FLTK 1.3.2 or
 higher (http://fltk.org), configured with OpenGL support. Support for
-constructive solid geometry requires OpenCASCADE 6.9.0 or higher
-(http://www.opencascade.com).
+constructive solid geometry requires OpenCASCADE 6.9 or higher (version 7.1 is
+highly recommended; http://www.opencascade.com).
 
 
 Build Gmsh from the command line