I use boost serialisation in my project and I need to serialise a vector of pointers (boost::shared_ptr) to a base class. The base class is declared in one dll in the following way: A.h: namespace boost { namespace serialization { class access; } } class A {... }; A.cpp #include <... boost serialization headers .. > BOOST_CLASS_VERSION(A, 1) .... In another dll I declare class B derived from A declared and implemented in the same manner ( .h files do not include boost serialization headers). The problem is that inside the sirialisation (save/load) function of the derived class I get correct file_version value while in the serialisation function of the base class file_version is 0. I call serialization function of the base class as advised in the documentation: ar & boost::serialization::base_object<A>(*this); However, if I insert BOOST_CLASS_VERSION(A, 1) into B.cpp then file_version in A's serialisation function is initialised properly. It is a pain to update the version of the base class in all derived classes from one side, it is also impractical to include all boost headers and class version information into .h files since the compilation time grows dramatically and the size of the executables increases several times. Any thoughts and suggestions are welcome! Thank you in advance, Mikhail