According to Kodansha's website, Hoozuki no Reitetsu
will include three OVAs in limited editions of volume 17 to 19, releasing February 23, 2015, May 22, 2015, and August 21, 2015, respectively. The streaming event for OVA has also been decided to be in December 2014.
The TV series
aired from January to April 2014.
Source: Kodansha site
Hoozuki no Reitetsu OVA