It was announced on Ore no Imouto ga Konnani Kawaii Wake ga Nai's (Oreimo) official website that the episode 12 of the True Route version of the anime will stream in late February for two weeks!
The three sites are Nico Nico Douga, Showtime, and Moviegate (mobile site & iPhone, iPad). More details will be announced in the March issue of Dengeki G's Magazine.
It was explained last time by Aniplex producer. Atsuhiro Iwakami that there are two versions of episode 12, one being the "good end" and the other, being the "true route" of the story which will end at episode 15.
Source: Saishin Anime Jōhō via ANN