diff --git a/include/fmt/format.h b/include/fmt/format.h
index f5835d9d..42f0bdac 100644
--- a/include/fmt/format.h
+++ b/include/fmt/format.h
@@ -2111,15 +2111,12 @@ FMT_CONSTEXPR OutputIt write(OutputIt out, T value) {
   return base_iterator(out, it);
 }
 
-template <typename Char, typename OutputIt, typename T,
-#ifdef __cpp_lib_byte
-          FMT_ENABLE_IF(std::is_enum<T>::value &&
-                        !std::is_same<T, Char>::value &&
-                        !std::is_same<T, std::byte>::value)>
-#else
-          FMT_ENABLE_IF(std::is_enum<T>::value &&
-                        !std::is_same<T, Char>::value)>
-#endif
+template <
+    typename Char, typename OutputIt, typename T,
+    FMT_ENABLE_IF(
+        std::is_enum<T>::value && !std::is_same<T, Char>::value &&
+        mapped_type_constant<T, basic_format_context<OutputIt, Char>>::value !=
+            type::custom_type)>
 FMT_CONSTEXPR OutputIt write(OutputIt out, T value) {
   return write<Char>(
       out, static_cast<typename std::underlying_type<T>::type>(value));