Why is BinaryFormatter not supporting Version Tolerance? - unity3d

Question

According the the .NET docs, Version Tolerance was added to BinaryFormatter in .NET 2.0:
https://msdn.microsoft.com/en-us/magazine/cc163902.aspx#S10
So in theory, I should be able to remove a field from a Serialized class, and not have things blow up. ie:
//Version 1
SaveData {
public int Num1;
public int Num2;
}
//Version 2
SaveData {
public int Num1;
}
Even though I removed Num2, the older versions of the class should still deserialize ok, due to Version Tolerance: "In the case of removing an unused member variable, the binary formatter will simply ignore the additional information found in the stream. "
https://msdn.microsoft.com/en-us/magazine/cc163902.aspx#S10
Instead, Unity is throwing an Error:
System.Runtime.Serialization.SerializationException: Field "Num2" not found in class SaveData
Is there a way to get this working in Unity?
[Edit] Here's the code I'm using to Save/Load:
//Save
BinaryFormatter bf = new BinaryFormatter();
FileStream fs = File.Create(path);
bf.Serialize(fs, data);
fs.Close();
//Load
BinaryFormatter bf = new BinaryFormatter();
FileStream fs = new FileStream(path, FileMode.Open);
SaveData data = (SaveData)bf.Deserialize(fs);
fs.Close();

Answer 1

First of all, BinaryFormatter could be weird (I dont test this case myself), because Unity use some weird version of Mono instead of MS.NET. So, .NET docs may lie :-< (Most of the the times, they work in same way)
Second, i use protobuf-net to do data-things in my Unity project. As so far, it works like a charm.