Since which Unity version is Undo.RecordObject available?

Hello.

I'm working on an asset for the asset store.
As I use the Undo class to allow undo for certain functions, and want the asset to be available for Unity version 4.1 and later, I have a problem.

When I open the asset in Unity 4.5, I get the message, that the method "Undo.RegisterUndo()" is obsolete and I should use the "Undo.RecordObject()" method instead.
This method is not available in Unity 4.1, so I would need to switch the used method depending on the used Unity version.

My question is now, since which Unity version is this new method available?

Greetings
Chillersanim