Not perfect, but anyway, here it is:

perl -F, -nae '$ok?(print $last):($ok=1) if ($F[3] ne (split/,/,$last)
+[3]); $last=$_; END{print $last;}' file
[download]

If you don't mind output ordering, or if the lines for a given ID are not consecutive, then

perl -F, -nae '$s{$F[3]}=$_; END{print values %s;}' file
[download]

(and it's simpler too).