Sega opened a teaser site with the title neXt39. There isn’t much on the site yet aside from the number 3939. How does this number connect to Hatsune Miku? 3939 is kind of a pun on “Miku Miku” if you read “3” as kunyomi you would have mitsu or mi. Mix that with the onyomi reading for “9” which is kyu or ku and you get “Miku.”
Gamestalk also reports Sega was looking for illustrations for a new Hatsune Miku project on August 10. Together, this information means a new Hatsune Miku game is likely on the horizon.