Hi everyone, I am encountering a particularly gnarly version of the backward-compatibility problem with binary archives that others have discovered (here: http://groups.google.com/group/boost-list/browse_thread/thread/f4e3287f6925f..., for example). Specifically, I have a number of binary archives created with version 1.43 of the library that are unreadable using version 1.47. I'd like to "port" them forward, so my initial plan was to compile a simple translator program against the 1.43 library that would read the binary archives and save them as (1.43) text archives. Then, a second program compiled against the 1.47 library would read the text archives and save them as (1.47) binary. Easy peasy. Except: the archives contain NAN values, which work fine when everything is binary but fail to deserialize for any version of the library when the archive is text (or xml, apparently), for reasons I don't quite understand. So my question is: how can I take my (1.43) binary archives containing NAN values and get them into a format readable by the current (1.47) version of the library? Is it possible? Thanks, Terry (An aside: it seems strange that I'm allowed to serialize a NAN to text, but it breaks when I try to deserialize it... why not prevent the creation of un-deserializable archives at the point of serialization?).