Backwards compatibility in .NET with BinaryFormatter

Question

We use BinaryFormatter in a C# game, to save user game progress, game levels, etc. We are running into the problem of backwards compatibility.

The aims:

Answer 1

Tough one. I would dump binary and use XML serialization (easier to manage, tolerant to changes that are not too extreme - like adding / removing fields). In more extreme cases it is easier to write a transform (xslt perhaps) from one version to another and keep the classes clean. If opacity and small disk footprint are a requirement you can try to compress the data before writing to disk.