Hello,
Unfortunately, Collaborator doesn't have such a filter. However, there are some workarounds.
There is the "Show advanced mode" button at the top of the DiffViewer. If you click it, two drop-down lists will appear, before and after. In each of them, you can choose the file version to display on the correspondent side of the page. The items in the drop-downs are shown not only with the upload number but also with the timestamp, which makes it easier to choose the correct file version.
Besides, when a new file version is uploaded, a new system message indicating the file version upload is added in the chat section. You can utilize the Accepted button to mark the file versions that have already been reviewed (See Accepted.png). This will help you to trace the file versions that were reviewed before, and the latest reviewed version.
