View and Compare version history of Business Process

Click on Resource Library on the left and expand the folder containing the Business Process
Click on the Business Process to view the detail and the version history on the right details panel
Click on the Version Info tab on the detailed panel
You will see all version history with comments.
You can download any older version if needed by clicking on the download icon on the right.

Compare two versions of Business Process

From the version history tab select the two versions you want to compare (Click on the check boxes against the versions)
a Compare button will appear as below
Click on Compare
You can see the differences highlighted