Although the Duffer Brothers plan out most of season 5, which will be the last installment, there is no way to know when filming will start. 

Sadie Sink stated that the last season took over two years, and she doesn’t know how much longer season five will be. Deadline. Although the Duffers are aware that their fans will eagerly await a fifth season of The Duffers, I do not believe they will hurry it. They want to make it the best season possible.”

Although they won’t rush them, it appears that they are reducing the number of scenes for the final season. Although the Duffer Brothers promise that the next episodes will be shorter than the previous, they expect the final episode to be longer. 

Matt Duffer said that “the only reason we don’t anticipate to be as lengthy is this season. If you look at it…it’s almost a 2-hour ramp-up before our children really get drawn in to a supernatural mystery.” Joyful and Sad Confusion podcast. “You meet them, get to know their families, and you see what they are going through. Steve has been struggling with high school transitions. Steve also is looking for a partner. This is clearly not what will happen. [in season 5].”