in boost/serialization/shared_ptr.hpp, line 133: in the case of NOT "#ifdef BOOST_SERIALIZATION_SHARED_PTR_132_HPP" the variable file_version is not used. Could be fixed by replacing else #endif by else #else (void)file_version; #endif or something similar. Would be great if that could be fixed for the next release. Keep up the great job! Best regards Christoph