"Flavio Antonioli" wrote in message news:6.2.3.4.0.20050827202716.074f4108@69.56.206.138... Hello, is serialization class versioning supposed to allow old versions of a program that serializes an old version of a class to load files saved with a newer version that saves some extra data? It doesn't seem to be able to do it, but it would be a very useful feature. The docs mention the fact that new versions can read old version classes, they don't mention if old versions can load newer versions files. Unless I'm missing something, which is not unlikely, it should be relatively easy to implement, the xml readed should simply skip fields that it doesn't recognize. I never considered this. I wouldn't do it as it would break symetry between xml and other archives. But you might be implement this with a derivation of xml_archive. Robert Ramey