Stranger Things was in the midst of filming it's fourth season when production was halted by the COVID-19 pandemic. However, creators Ross Duffer and Matt Duffer recently spoke about their show with The Hollywood Reporter and how the quarantine has allowed them to perfect the scripts for the new season's plan:
“We’ve had a lot more time to work on the scripts. For the first time, we have all the scripts written and we’re able to look at it as a whole piece and make adjustments.”
In this same interview, they also confirmed that, despite previous comments from Matt Duffer, the upcoming fourth season, which might recommence production before the end of the year, will not be the show's last:
“Season four won’t be the end. We know what the end is, and we know when it is. [The delay] has given us time to look ahead, figure out what is best for the show. Starting to fill that out gave us a better idea of how long we need to tell that story.”
It's been teased that the show might go on for a fifth season for some time, but with the quarantine giving creative forces time to rethink their shows, who knows. Perhaps it follows The Crown who, while originally having six seasons planned, at one point was only going to do five before the writers changed their mind. Time will tell, judging by how long the creators will remain in the Upside Down. Stay tuned!