Until now, we have basically treated the ITP/MDK Repository as an ordinary file system. This view is sufficient for many day-to-day tasks. There will be situations however, in which you will need access to older versions of a document, a model, a Text Block or another object.
If you look closer at the ITP/MDK Repository, it is not a file system, but an archive that keeps track of all versions of your objects, also known as revisions. Whenever you start editing a file, you do not edit the original file, but a copy. And whenever you unlock the file, the original file does not get overwritten, but your edited copy gets placed next to it, as a new revision.