The next Gintama movie now confirmation that it will be based on the manga , but with some extra elements.
In the image above that reveals the film's look, you can see the slogan “Bye bye, Gin-san.”
The Gintama film will premiere in Japan on January 8, 2021, and is therefore billed as “the finale, this time for real.”
The manga is also inspiring a new anime special, with a story that will connect to the film. It will premiere exclusively in Japan on the online digital TV service in early 2021.
Source: ANN