diff --git a/libcxx/include/fstream b/libcxx/include/fstream
--- a/libcxx/include/fstream
+++ b/libcxx/include/fstream
@@ -554,7 +554,7 @@
   case ios_base::in | ios_base::out | ios_base::app | ios_base::binary:
   case ios_base::in | ios_base::app | ios_base::binary:
     return "a+b" _LIBCPP_FOPEN_CLOEXEC_MODE;
-#if defined(__cpp_lib_ios_noreplace)
+#if _LIBCPP_STD_VER >= 23
   case ios_base::out | ios_base::noreplace:
   case ios_base::out | ios_base::trunc | ios_base::noreplace:
     return "wx" _LIBCPP_FOPEN_CLOEXEC_MODE;
@@ -679,7 +679,7 @@
         case ios_base::in | ios_base::app | ios_base::binary:
             __mdstr = L"a+b";
             break;
-#  if defined(__cpp_lib_ios_noreplace)
+#  if _LIBCPP_STD_VER >= 23
         case ios_base::out | ios_base::noreplace:
         case ios_base::out | ios_base::trunc | ios_base::noreplace:
           __mdstr = L"wx";
diff --git a/libcxx/include/ios b/libcxx/include/ios
--- a/libcxx/include/ios
+++ b/libcxx/include/ios
@@ -277,7 +277,7 @@
     static const openmode ate    = 0x02;
     static const openmode binary = 0x04;
     static const openmode in     = 0x08;
-#if defined(__cpp_lib_ios_noreplace)
+#if _LIBCPP_STD_VER >= 23
     static const openmode noreplace = 0x40;
 #endif
     static const openmode out   = 0x10;