2 of 4 Added more info

The 2011 series covers roughly chapters 1 to 339 of the manga, as documented in this answer by Frosteeze.

Since then, 21 new chapters have been released (as of september 2016, see here or here).

In addition to "The Last Mission", another anime film was released in 2013, "Phantom Rouge".

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Other than that, you have the original 1999 series, a set of 30 OVA episodes, and a 1998 short film, "Jump Super Anime Tour 98". None of them include material not covered by the 2011 series, as far as I know.

EDIT: In addition to all that has been previous stated, it has recently been announced that the manga is getting a continuation in 2016, as stated here.