The 3.10 release of FileField is a minor maintenance release to fix a few issues around files that have gone missing (by manually moving or crufty data) or when using FileField Meta. It also includes a few minor features.
#791118: warning: array_merge(): Argument #2 is not an array (and it's similar cousin...)
#857938: Argument #2 is not an array in /sites/all/modules/filefield/filefield_widget.inc on line 255
#1018850: Views file data description shows encoded characters
#1001574: filefield_file appears twice in hook_theme()
#1007076: Views formatter for Duration works only with Default format, not with "seconds" or "minutes"
#1021356: Notice: undefined $item['fid'] in filefield_widget.inc
#1080620: Incorrect string value error when uploading mp3 file; Ignore music_cd_identifier id3 tag
#1126198: Allow users without "access content" permission to upload files
#1132764: Filefield upgrade enters infinite loop while updating nodes with more than 50 attachments