KNiTO uses the term Edition loosely. In other words, we do not technically force any publisher to commit to creating editions of their books. However, as a publisher you might wish to update your book content and for example create the same book with modified content, extra chapters, updated content, etc and call it Edition 2, 3,...
KNiTO has a predefined and well-observed "revision" feature. ePUB3 books are very much like software applications which keep on evolving and upgrading and have different versions. We do not use this term and instead we let publishers create different revisions of their book. This lets you add minor changes, alterations to both content and metadata and release it. This will automatically increase your revision number. Older revisions will be unpublished, but those readers who have already bought them are still able to download to their device and read. Readers will be notified and are able to decide and download the latest revision.