Most content types support revision histories, allowing content managers to view and revert to previous versions of content.

When editing an existing content item (e.g. Page, News, Event, etc), a revision will be created automatically by default. Most content types allow you to not create a revision for the update by unchecking the Create new revision checkbox:

Revision control checkbox and log message on a content edit form

An optional revision log message can also be provided which can be helpful to describe the reason you're making an update to the page.

Viewing Previous Revisions

After at least one revision for a page exists, you can view the previous versions if desired.

When viewing the page as a logged in content manager or site admin, click the Revisions tab:

Local task link tabs for a content item with the Revision tab highlighted

This brings you to a page that lists all previous revisions of the content item, along with the date, who made the change, and the log message (if provided). Clicking each revision date allows you to view the content from that specific version.

Comparing Revisions

On the revisions tab, you can use the radio input buttons in the A and B columns to select two revision to compare. This can be helpful if you want to see exactly what was changed. After making one selection from each column, press the "Compare selected revisions" button at the bottom of the list.

Revisions overview showing two revisions for a page

The comparison page allows you to compare the content using three different layouts:

  • Split fields (default): For each field that's different between the revisions, show the differences in a two column layout and highlight the differences.
  • Unified fields: Similar to split fields, except two columns are not used. An attempt is made to highlight any differences directly inline with the field content.
  • Visual inline: This method outputs the page using your site's theme and attempts to highlight any differences visually wherever the content would normally appear.

No method is better than the other, and which method is the most useful depends on the content type and nature of the changes. Some differences between two revisions will not be visible in one or more of the comparison methods. You are encouraged to try each option as needed.

Reverting to Previous Revisions

You may need to revert a content item to a previous version. After identifying which revision you want to revert to, simply click the Revert button alongside it in the revisions table and proceed through the confirmation screen.

When reverting to a previous revision, a new revision is created from that older version.

Caveats and Known Issues

Error Message When Saving Block

When reverting to a previous revision of a Page that has general purpose blocks placed on it (e.g. Text block, Feature block, etc), you may encounter an error when attempting to make changes to the blocks:

Error message reading "The content has either been modified by another user, or you have already submitted modifications. As a result, your changes cannot be saved."

This is a known issue that will be resolved in a future release. The only workaround is to remove the block from the layout and recreate it.

Revisions Comparison Shows No Changes

When comparing two revisions, you may not be able to see any changes between the two versions, even after trying all three layout options. This may be because there were no changes, as it's possible to save a revision without making any changes to the content. It may also be because the nature of the change cannot be visualized.