All Box accounts come with 'Version History' which allows you to maintain a recent history of a file. If previously uploaded within the same directory, the file will overwrite itself and become the current version on the account.
With Version History, a history of previous file versions will remain intact and you will be able to recall previous versions of the uploaded file.
To locate the version history window, click on the little box with the downward arrow and select 'Version History' from the 'File Properties' sub menu.
On this pop-up window you can revert back to an older version of the document by choosing "Make Current," download an older version by choosing "Download," or delete a previous version by choosing the red "X"