Sentai Filmworks confirmed with ANN that its license for the Night Raid 1931 (Senkō no Night Raid) anime has expired and its home video releases are out of print. The series is still streaming on Crunchyroll.

The 13-episode series aired in Japan in 2010 and had two unaired episodes for the Japanese home video release. Sentai Filmworks announced its license for the full series in 2011 and released it on Blu-ray Disc and DVD the same year.

The story of the anime is set in 1931 in Shanghai, when the Imperial Japanese Army has been dispatched to mainland China due to the relatively recent First Sino-Japanese War, Russo-Japanese War, and World War I. In this cosmopolitan city of intrigue, there is a special military spy organization called "Sakurai Kikan" that has since been buried in history.

Thanks to kenno20081 for the news tip.

Source: Email correspondence