diff --git a/c++/app4triqs/app4triqs.hpp b/c++/app4triqs/app4triqs.hpp
index f9663000..d7ce7fc1 100644
--- a/c++/app4triqs/app4triqs.hpp
+++ b/c++/app4triqs/app4triqs.hpp
@@ -59,7 +59,8 @@ namespace app4triqs {
     friend void h5_read(h5::group grp, std::string subgroup_name, toto &m);
 
     /// Serialization
-    template <class Archive> void serialize(Archive &ar) { ar &i; }
+    void serialize(auto &ar) const { ar &i; }
+    void deserialize(auto &ar) { ar &i; }
   };
 
   /**