During a recent livestream (via Dualshockers) with Yakuza producer Toshiro Nagoshi, he teased that Sega have been thinking about doing remakes for Yakuza 2 through Yakuza 5.
This was prompted after Yakuza: Kiwami, the remake of the very first game in the series, was reported to have sold over 500,000 copies in both Japan and Asia.
It wasn’t specified whether or not these would be remakes in the style of Yakuza: Kiwami or simply updating all the models and textures with ones from the most recent games, in an HD-remaster style.
As of now, Yakuza 6 is currently planned at being the very last Yakuza game with Kazuma Kiryu as the protagonist. It is slated to release on December 8th, 2016 in Japan for the PS4.