Essential capabilities of content management are the abilities to view the 'change history' of a content item, to compare various versions with one another, and optionally, to revert to a previous version of a content item.

In this article, Darci Hanning discusses how to use versioning in Plone to examine the history of changes made to a content item, to preview and compare versions, and to revert to a previous version of a content item.

(For more resources on Plone, see here.)

Introducing versioning

Now that you have learned how to add various types of content, from pages to events to news items, we're ready to introduce a feature of Plone called versioning, which is an important part of content management. The content items you work with in your Plone site may go through many changes over time. Plone provides versioning information to help you manage your content from the time it was initially created through to the current version.

By default, Plone provides versioning for the following content types:

• Pages
• News Items
• Events
• Links

Other content types can be configured to provide versioning through the Plone Control Panel under Types.

Although you may enable the File type to use versioning, the only changes that are tracked are those items actually describing the File (for example, Title, Description, and so on). The changes to the contents of the File are not tracked.

Creating a new version

Versions are created each time you save your content. Note that there is a Change note field at the bottom of the Edit page for content items with versioning enabled:

The information entered in the Change note field will be stored along with other versioning information, which you are able to view through the History tab.

Viewing the version history

You can view the list of all of the versions of a content item by clicking on the History tab for that content item. In the History view that you can see in the following screenshot, the most recent version is listed fi rst. Clicking on any of the column headers will re-sort the listing based on that column heading.

The most current version is always labeled Working Copy in the History view.

Previewing previous versions

To preview a specific version, simply click the preview link of the desired revision. In the following example, revision 3 has been identified, and will be displayed if this link is clicked:

On the subsequent page, you may either click on the jump down link to the point of the content preview:

or you may scroll down the page in order to see the actual preview: