Documents in the community support versioning and allow you to view changes between current and prior versions.
View Prior Version
By default the prior version and the current version will appear side by side, but you can toggle the radio buttons to compare the changes in the HTML Markup, or view the changes in the current revision as a single page. Green highlights indicate content addition, red indicate content deletion, and purple indicate a change to existing content (such as adding a hyperlink).
View Additional Versions
If a document has more than two versions, you can choose which versions you want to compare by using the revision drop-down menu.
To view a prior version in its entirety without comparison to other versions, click the name of the version.
When you view a prior version, you'll be notified that you're viewing an archived version of the document. To view the current version, click the updated link.