According to Fujimishobo, a new OVA of Maken-Ki! was announced to be released in September. It will be bundled with the 11th volume of the manga.
New Staff
Director: Kaneko Hiraku
Character Design: Takami Akio
Script: Kuroda Yosuke
Production Studio: Xebec
It’ll be a fanservice episode in a tropical island.
Source: Fujimishobo