The news was reported on the official Twitter accounts for the arcade game series, the anime, and the voice actress unit Run Girls, Run!
The “Pretty All Friends” project to celebrate its ten anniversary was revealed in December 2017 and has released various crossover stories on its website.
At 19:00 (JST) / 03:00 (PT) on the memorial day, the official YouTube channel for its ongoing TV anime series Kiratto Pri☆Chan will stream “an important announcement video.”