Rob Alain posted a post about file uploads on his blog. Small note - Rob describes the very basics. The main thing, in my opinion, is the Conclusion.
That's where Rob calls for more cautious use of the current version of the component and wait for version 1.7.2. In particular, the Count validator does not always work as it should, as well as the getValues () and receive () methods — they are not “smart” and it happens that they call move_uploaded_file () several times.
So, colleagues, be attentive!