--- contrib/tools/cython_py2/Cython/Utility/CppSupport.cpp	(index)
+++ contrib/tools/cython_py2/Cython/Utility/CppSupport.cpp	(working tree)
@@ -83,20 +83,11 @@ auto __Pyx_pythran_to_python(T &&value) -> decltype(to_python(
 
 ////////////// OptionalLocals.proto ////////////////
 //@proto_block: utility_code_proto_before_types
-
-#include <utility>
-#if defined(CYTHON_USE_BOOST_OPTIONAL)
-    // fallback mode - std::optional is preferred but this gives
-    // people with a less up-to-date compiler a chance
-    #include <boost/optional.hpp>
-    #define __Pyx_Optional_BaseType boost::optional
-#else
-    #include <optional>
-    // since std::optional is a C++17 features, a templated using declaration should be safe
-    // (although it could be replaced with a define)
-    template <typename T>
-    using __Pyx_Optional_BaseType = std::optional<T>;
-#endif
+#include <optional>
+// since std::optional is a C++17 features, a templated using declaration should be safe
+// (although it could be replaced with a define)
+template <typename T>
+using __Pyx_Optional_BaseType = std::optional<T>;
 
 // This class reuses as much of the implementation of std::optional as possible.
 // The only place it differs significantly is the assignment operators, which use