diff --git a/thirdparty/pegtl/pegtl/demangle.hpp b/thirdparty/pegtl/pegtl/demangle.hpp
index 97b2606528..243637a139 100644
--- a/thirdparty/pegtl/pegtl/demangle.hpp
+++ b/thirdparty/pegtl/pegtl/demangle.hpp
@@ -5,7 +5,8 @@
 #ifndef TAO_PEGTL_DEMANGLE_HPP
 #define TAO_PEGTL_DEMANGLE_HPP
 
-#include <ciso646>
+// ciso646 is deprecated and generates warning messages with gcc 15
+//#include <ciso646>
 #include <string_view>
 
 #include "config.hpp"