Update: Official announcement can be found here. It confirms that Hatsune Miku: Project Mirai Remix is based on Mirai 2.
Hatsune Miku: Project Mirai Remix is heading overseas, SEGA has announced. It will be released throughout the west and Asia in 2015.
Hatsune Miku: Project Mirai Remix will be the full localized version of the original game. SEGA seems to be including new elements as well.
SEGA announced today’s news during a Hatsune Miku talk show that was broadcasted on Niconico. The title will commemorate the series’ 5th anniversary.