Hi Robert, I've just updated by Boost tree and run in a number of compile errors. One is pretty easy -- I've committed the attached trivial patch to split_member.hpp. Another is this: ....boost/boost/archive/detail/oserializer.hpp:551: error: incomplete type `boost::STATIC_ASSERTION_FAILURE<false>' does not have member `value' instantiated from this code of mine: ofstream ofs(av[2]); boost::archive::binary_oarchive oa(ofs); oa << *data_builder.finish(); Where 'finish' returns auto_ptr<Data>. It's looks like serialization checks if the serialized type is 'const' and if not, complains. Basically, it's some heuritic to prevent saving on-stack object (though I don't understand why it would work at al). I find this a bit too much . I have no reason whatsoever to make 'finish' return auto_ptr<const Data>. And writing oa << const_cast<const Data&>(*data_builder.finish()); looks very strange. And modifying all places where I get this error is not nice too. So, can this static assert be removed? Then, I get ambiguity in iserializer.hpp, in this code: #ifndef BOOST_NO_FUNCTION_TEMPLATE_ORDERING template<class Archive, class T> inline void load(Archive &ar, const serialization::nvp<T> &t){ load(ar, const_cast<serialization::nvp<T> &>(t)); } For some reason, both boost::archive::load and some other 'load' in 'boost' namespace (part of earlier serialization lib) that I still use are considered overload candidates. Adding explicit boost::archive:: fixes this. See attached patch. Then I get error at this code: ar << boost::lexical_cast<std::string>(*this); The error message is: error: no match for 'operator<<' in 'ar << boost::lexical_cast(Source) [with Target = std::basic_string<char, std::char_traits<char>, std::allocator<char> >, Source = lvk::nm_model::BlockFormula]()' /space/NM/boost/boost/archive/detail/interface_oarchive.hpp:75: error: candidates are: Archive& boost::archive::detail::interface_oarchive<Archive>::operator<<(T&) [with T = std::basic_string<char, std::char_traits<char>, std::allocator<char> >, Archive = boost::archive::binary_oarchive] ...unrelated operator<< definitions snipped... Apparently, passing rvalue to "T&" does not work. Yes another attached patch fixes this issue. - Volodya