Canto allows for different versions of an asset to be uploaded, downloaded, and shared. A new version can be any variation of the file, even a different file format of the same type (e.g. a .jpeg file can be replaced with a .png file; a .mp4 file can be replaced with a .mov file).
To see the different versions of an asset, navigate to it and open the Information Page.
You might need to scroll down until you find the Versions section.