According to Jump Square magazine, another OVA of To LOVE-Ru Darkness
was announced to be released on December 19th. It will be bundled with the sixth volume of the comic book. Chapter 19 "Nostalgia" and two extra chapters "Flower" and "The changing heart" will be animated.
To Love-ru anime official website
The first volume of the OVA
will be released on August 17th and the TV series
will start this October.
Source: Scan of Jump SQ