I eventually managed to get everything to work nicely Just one essential bit that seems to be missing in the docuemntation...at least I missed it :-) **** Use the ***DLL version*** of boost serialization (#define BOOST_ALL_DYN_LINK or BOOST_SERIALIZATION_DYN_LINK in your build) Otherwise, afaict, every DLL gets a separate static extended type-info singleton container. **** And, to anwer my own question, the documentation does say explicitly that non-rtti and rtti implementations of extended type-info can coexist. Hopefully, this will help other newbies!