compare or go back to an older version of content

On our drupal server a revisioning system is installed. The revisions
allow to compare and revert to an older version of the content.
Editors will see the "revision tab". Here you can inspect the history
and compare versions of your content. In "edit mode" you can switch
to older versions and revert (change back) to the displayed version.
The revert operation will copy (create new) the old version to a new
versions at the new time stamp.

Each time the content is saved , a new revision will be  created.
Please do not uncheck the "create new Revision, no moderation"
checkbox in the "revision information" bar.