We’re planning a history feature to show how a notebook has changed over time. Authors will be able to browse every version, while readers will only be able to see published versions. Authors will also be able to restore work, say by reverting to an earlier version or cherry-picking changes. And forking, too, of course.
For this to work well, I expect we’ll want a way of attaching notes to specific versions (the equivalent of git tags or commit messages), since the number of automatically-saved versions quickly becomes unmanageable. But version notes should likely not be limited to publishing, since you may want this ability for private notebooks, and you may want to tag versions prior to publishing.
If you update a published notebook in a meaningful way, a good journalistic practice is to add a correction note to the notebook itself, either at the top or the bottom depending on how significant the correction is.