diff --git a/include/boost/archive/detail/utf8_codecvt_facet.hpp b/include/boost/archive/detail/utf8_codecvt_facet.hpp
index 5956feb5..9faba38e 100644
--- a/include/boost/archive/detail/utf8_codecvt_facet.hpp
+++ b/include/boost/archive/detail/utf8_codecvt_facet.hpp
@@ -9,8 +9,7 @@
 
 #include <boost/config.hpp>
 
-//#ifdef BOOST_NO_CXX11_HDR_CODECVT
-#if 1
+#ifdef BOOST_NO_CXX11_HDR_CODECVT
     #include <boost/archive/detail/decl.hpp>
     #define BOOST_UTF8_BEGIN_NAMESPACE \
          namespace boost { namespace archive { namespace detail {