The volume shipped in Japan in October 2014, though Dark Horse has not released a new volume of Drifters since March 2014.
Dark Horse Comics revealed in its June solicitations that it plans to release the fourth volume of Kouta Hirano’s Drifters manga on August 9.
Hirano (Hellsing) launched the manga in 2009 and Dark Horse licensed the series the following year.
Dark Horse also confirmed with ANN that it will release the fifth volume — the most recent volume that Shonengahosha has released in Japan — in December.