On the official Twitter account for P.A Works Shirobako anime that the team is working on a movie but it’s unrelated to Shirobako. Now the post further added that more people have been added to the project and is tackling a subject different from the TV version. However it has not been stated as to what TV version it is. The anime Shirobako originally started airing October 9th 2014 and ended March 25th 2015 releasing 24 episodes in total. The series originally is adapted from a novel that started and ended on January 27th 2015 with one volume released for it. Its prequel was a manga that released two volumes which started September 27th 2014 and ended November 27th 2015. A two episode special was also released on February 25th 2015 and would end July 29th 2015. Finally a plot summary of the series is as follows quoted from MAL:
Aoi will never forget how she felt the day her high school animation club’s labor of love was shown at the cultural festival. The sense of awe and the feeling of accomplishment that came with completing their very first project are exactly what encouraged Aoi and her club mates to enter the animation industry in the first place. But two years later Aoi has graduated, and now that she works as a production assistant for a big-name animation studio, the daunting reality of her job has somewhat diminished her enthusiasm. Despite the long hours and the punishing schedule, Aoi still hopes to fulfill the promise she and her club friends Ema, Shizuka, Misa, and Midori made: to one day reunite and make a real animated feature of their own as professionals!