I have successfully been using the force_download functionality, that is, until a client tried using it behind a firewall.
It seems the line:
places a hex /x22 (or “) around the content type. From the info I’ve received, \x22application/octet-stream\x22 for example is not a valid type. Changing lines (the code appears on lines 74 and 84 of download_helper.php) to:
fixed the problem. Should this change be adopted in future releases?