diff --git a/Straight_skeleton_2/include/CGAL/create_offset_polygons_2.h b/Straight_skeleton_2/include/CGAL/create_offset_polygons_2.h
index 0283ced78aaa..2a2a481dab07 100644
--- a/Straight_skeleton_2/include/CGAL/create_offset_polygons_2.h
+++ b/Straight_skeleton_2/include/CGAL/create_offset_polygons_2.h
@@ -141,7 +141,7 @@ template<class OutPolygon, class FT, class Skeleton, class K>
 std::vector< boost::shared_ptr<OutPolygon> >
 create_offset_polygons_2 ( FT const& aOffset, Skeleton const& aSs, K const& , Tag_false )
 {
-  static_assert(!std::is_same_v<OutPolygon, CGAL::Default>);
+  static_assert(!(std::is_same<OutPolygon, CGAL::Default>::value));
 
   typedef boost::shared_ptr<OutPolygon> OutPolygonPtr ;
   typedef std::vector<OutPolygonPtr>    OutPolygonPtrVector ;
@@ -167,7 +167,7 @@ template<class OutPolygon, class FT, class Skeleton, class K>
 std::vector< boost::shared_ptr<OutPolygon> >
 create_offset_polygons_2 ( FT const& aOffset, Skeleton const& aSs, K const& /*k*/, Tag_true )
 {
-  static_assert(!std::is_same_v<OutPolygon, CGAL::Default>);
+  static_assert(!(std::is_same<OutPolygon, CGAL::Default>::value));
 
   typedef boost::shared_ptr<OutPolygon> OutPolygonPtr ;
   typedef std::vector<OutPolygonPtr>    OutPolygonPtrVector ;