Studio BONES announced that it will produce a new film trilogy for the Eureka Seven anime franchise titled Kōkyōshihen Eureka Seven Hi-Evolution (Psalms of Planets Eureka Seven Hi-Evolution). The first film will open in Japan this year, and the next two films will open in 2018 and 2019, respectively.
The films will follow The First Summer of Love phenomenon that occurred a decade before the first Eureka Seven series. The films will then have the same basic story as the first Eureka Seven series, but will have an original ending.
For anyone wondering, Kenichi Yoshida might have confirmed (other translations pending) he did the Eureka SeveN Hi-Evolution illustrations
After @planetaryoratorio & @limitofquestions looked into translations of the tweet from Japanese it seems Yoshida was most likely referring to drawing a NEW illustration for Eureka SeveN Hi Evolution currently. Whether he is the artist of the poster art is still unknown officially.