An interview with Akiyo Iyoku, head of Shueisha’s Dragon Ball Room, was included in the movie's Japanese DVD and Blu-Ray release. In the brief interview, Iyoku admits that the team is "steadily making preparations for the next Dragon Ball movie." He doesn't share any more details about the project but teases that "things will probably head in a completely different direction next time around."
No release date or window for the next Dragon Ball movie was provided, but Iyoku says he's excited for everyone to see "what’s coming up next." He concludes by suggesting that "whatever comes next will be even more incredible."
Source
I am surprised they are going with a sequel instead of an entirely different story.