MB Revision  extension for Meta Box allows you to track changes of the custom fields for post revisions: saving, comparing and restoring data from revision. It supports all field types, including groups and provides an easy way to see the changes in each revision. What is revision? As WordPress Codex states : The WordPress revisions system  stores a record of each saved draft or published update . The revision system allows you to  see what changes were made in each revision  – what was added, what remained unchanged, and what was removed. Lines added or removed are highlighted, and individual character changes get additional highlighting. Click the ‘Restore This Revision’ button to restore a revision. By default,  WordPress tracks the changes only for post title and post content . The MB Revision enables the tracking for custom fields as well. If you store a lot of data in the custom fields and want to see the changes that your users made, this is the extension for you. Why tracking revisions for custom fields is important? Because your data is not only post title and post content! For large websites, creating pages such as landing pages, project pages requires custom data, which are stored in the custom fields. They’re very important that modifying them carelessly might cause big decrements of leads or sales. So you need to make sure every time you edit, you do it right. Another situation is when your website has many users that can edit the content. What if someone changes a field while he’s sleepy or distracted? How do you know  who did that  when it happens? For those reasons, to prevent unexpected changes in the website content, you  need to track revisions for all kind of content  you might have.