diff --git a/include/boost/system/detail/error_code.hpp b/include/boost/system/detail/error_code.hpp
index 2b387fb..b8833b3 100644
--- a/include/boost/system/detail/error_code.hpp
+++ b/include/boost/system/detail/error_code.hpp
@@ -335,30 +335,11 @@ public:
         }
     }
 
-#if !defined(BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS)
-
     BOOST_SYSTEM_CONSTEXPR explicit operator bool() const BOOST_NOEXCEPT  // true if error
     {
         return failed();
     }
 
-#else
-
-    typedef void (*unspecified_bool_type)();
-    static void unspecified_bool_true() {}
-
-    BOOST_SYSTEM_CONSTEXPR operator unspecified_bool_type() const  BOOST_NOEXCEPT // true if error
-    {
-        return failed()? unspecified_bool_true: 0;
-    }
-
-    BOOST_SYSTEM_CONSTEXPR bool operator!() const BOOST_NOEXCEPT // true if no error
-    {
-        return !failed();
-    }
-
-#endif
-
     bool has_location() const BOOST_NOEXCEPT
     {
         return lc_flags_ >= 4;
diff --git a/include/boost/system/detail/error_condition.hpp b/include/boost/system/detail/error_condition.hpp
index b2da281..a53b4d9 100644
--- a/include/boost/system/detail/error_condition.hpp
+++ b/include/boost/system/detail/error_condition.hpp
@@ -158,30 +158,11 @@ public:
         }
     }
 
-#if !defined(BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS)
-
     BOOST_SYSTEM_CONSTEXPR explicit operator bool() const BOOST_NOEXCEPT  // true if error
     {
         return failed();
     }
 
-#else
-
-    typedef void (*unspecified_bool_type)();
-    static void unspecified_bool_true() {}
-
-    BOOST_SYSTEM_CONSTEXPR operator unspecified_bool_type() const BOOST_NOEXCEPT  // true if error
-    {
-        return failed()? unspecified_bool_true: 0;
-    }
-
-    BOOST_SYSTEM_CONSTEXPR bool operator!() const BOOST_NOEXCEPT  // true if no error
-    {
-        return !failed();
-    }
-
-#endif
-
     // relationals:
     //  the more symmetrical non-member syntax allows enum
     //  conversions work for both rhs and lhs.