How do I maintain deserialization compatibility across obfuscated and debug builds

//to avoid cross-versioning problems
public sealed class CrossVersionDeserializationBinder : SerializationBinder {
    public override Type BindToType(string assemblyName, string typeName) {
        Type typeToDeserialize = null;

        typeToDeserialize = Type.GetType(String.Format("{0}, {1}",
            typeName, assemblyName));

        return typeToDeserialize;
    }
}

[ProtoContract]
public class Foo {
    [ProtoMember(1)]
    public string Bar {get;set;}
}

[ProtoContract]
public class a12 {
    [ProtoMember(1)]
    public string a {get;set;}
}

[DataContract]
public class a12 {
    [DataMember(Name="Bar")]
    public string a {get;set;}
}