Zipcloud gives you multiple options to view previous file versions. To view these versions simply login to your online control panel at https://my.Zipcloud.com and click on 'View My Backed Up Files' from the left hand side bar.
Once you have found the file you want to view previous versions of, hover over the file name and click where the 'Versions' link appears.
This will take you to a detailed page of statistics about the file and any available versions of that file are there to download.