Returns whether the receiving subclass of
NSDocument supports Versions.
- macOS 10.7+
YES if the receiving subclass of
NSDocument supports Versions; otherwise
The default implementation of this method returns
[self autosaves. You can override it and return
NO to declare that
NSDocument should not preserve old document versions.
NO from this method disables version browsing and
revert, which rely on version preservation when autosaving in place. Returning
YES from this method when
NO will result in undefined behavior.