After one of your partners changes a file, how do you see the changes in an analysis or visual way?
Your partner can upload a new version, leave a sketch, or write a comment to let you know about a change. If you have notifications setup, then you'll get an email when any of these happen.
You can also compare changes between versions, which is very useful. For a visual comparison of what is different from one version to the next, see the steps, here.