When does Hey Arnold! return?

Hey Arnold! is an American animated television series. The show aired from October 7, 1996, to June 8, 2004. It centers on fourth grader Arnold Shortman, who lives with his grandparents in an inner-city tenement in the fictional city of Hillwood, Washington. A feature film based on the series was released in theaters on June 28, 2002.
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, including Seattle (my hometown), Portland (where I went to art school) and Brooklyn (the bridge, the brownstones, the subway)"; the city also contains inspirations from Chicago, such as a baseball field called Quigley Field (a reference to the real-life Wrigley Field)