My boss just gave me OK to discuss this, so here goes. Please excuse me if it has been brought up before. Please excuse me also if what follows is just downright stupid. A common drawback of various serialization libraries is the need to provide versioning code for each data structure to be serialized. This need not be the case for XML archives (and other formats that store NVPs). Because the program knows which data members it needs, and the names are stored in the archive, the program can leave any missing members in their current state (typically just after construction) and ignore any extra ones. After all, this is one of the ideas behind XML! More often than not this tactic is sufficient to handle versioning. When it's not, there's always the old way of explicit version checks. It seems that this should be easy to implement for boost::serialization. Just make two passes through the deserialization function. In the first pass, just collect information on data members to be deserialized into some kind of map keyed on tag. In the second pass, perform actual deserialization, looking at the map built in the first pass. Any tags in the archive but not in the map are ignored together with their contents. I'm not sure whether current serialization syntax can or should be used with this functionality. Best of luck, -- Anatoli Tubman PTC Israel (Haifa) Tel. (+972) 4-8550035 ext. 229