Japanese production company ufotable will be producing the new series, of which currently there is no word whether the series will be a remake of the original 2009 series or if it will follow a different storyline.
Ufotable founder Hikaru Kondo announced in July that the series would be produced, but did not indicate whether it would be a remake of the original series, if it would follow one of the other alternate storylines from the game, or if it would be an entirely new story altogether.
"Fate/stay night" is based on a visual novel game that had three endings depending on the path you took. It told the story of Shiro, a teenage boy who finds himself getting involved in the Holy Grail Wars after witnessing a battle, and finds himself the unwitting Master to Saber, a Servant whose goal is to protect her Master at all costs.
The original 2009 series was produced by Studio DEEN. It was followed by "Fate/Zero," a prequel series based on a novel released by game company Type-Moon and produced by ufotable, and more recently "Fate/kalied liner Prisma Illya," which tells the story of what would have happened if a character was a magical girl.