When does Hey Arnold! return?

Hey Arnold! is an American animated sitcom created by Craig Bartlett for Nickelodeon. It originally aired from October 7, 1996, to June 8, 2004. The show centers on fourth grader Arnold Shortman, who lives with his grandparents in an inner-city tenement. Bartlett's idea for the show is based on a minor character named Arnold who he created while working on Pee-wee's Playhouse.
Hey Arnold! takes place in the urban fictional American city of Hillwood. Creator Craig Bartlett described the city as "an amalgam of large northern cities I have loved" Bartlett drew inspiration from people he grew up with when creating the characters for the show.