diff --git a/ext/intl/config.w32 b/ext/intl/config.w32
index 8de0e1eff0fc9..f3c3e2cffd76a 100644
--- a/ext/intl/config.w32
+++ b/ext/intl/config.w32
@@ -126,7 +126,7 @@ if (PHP_INTL != "no") {
 			ADD_FLAG("LIBS_INTL", "iculx.lib");
 		}
 
-		ADD_FLAG("CFLAGS_INTL", "/EHsc /DUNISTR_FROM_CHAR_EXPLICIT=explicit /DUNISTR_FROM_STRING_EXPLICIT=explicit /DU_NO_DEFAULT_INCLUDE_UTF_HEADERS=1 /DU_HIDE_OBSOLETE_UTF_OLD_H=1");
+		ADD_FLAG("CFLAGS_INTL", "/std:c++17 /EHsc /DUNISTR_FROM_CHAR_EXPLICIT=explicit /DUNISTR_FROM_STRING_EXPLICIT=explicit /DU_NO_DEFAULT_INCLUDE_UTF_HEADERS=1 /DU_HIDE_OBSOLETE_UTF_OLD_H=1");
 	} else {
 		WARNING("intl not enabled; libraries and/or headers not found");
 	}