No, as far as I know. When you upload a file, you're given a link with some sort of hash that points to the file. The link you create is [myfile](blablahash1). If you upload a newer version of that file, and replace the link with [myfile](blablahash2), the effect is to have a new version of the file, but actually the old one is still there... forgotten. If you google around you'll find many concerns about it, and I found it annoying myself. What people usually do is to forget the old files until they run out of space, then delete them from the disk.
If you find any different solution, please share.
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