So I modified the wpcf7-dropbox-script.js file the same way you that you have it above.
In my form I use the following:
————————————–
<label> Upload your Music
[file* upload1 limit:20mb filetypes:mp3|wav|m4a|png|jpg|jpeg|gif id:file1] </label>
<label> Upload your Artwork
[file* upload2 limit:20mb filetypes:mp3|wav|m4a|png|jpg|jpeg|gif id:file2] </label>
————————————–
Under my DropBox Settings I have:
————————————–
File Input ID: file1 file2
————————————–
But when I test it I get nothing? Am I doing something wrong?