The hit movie Demon Slayer – Mugen Train (Kimetsu no Yaiba) will get a 7-episode, serving as a complement to its 2nd season which arrives on December 5th.
The episodes adapted from the film premiere tomorrow in Japan, October 10th. According to reports, the first episode shows Rengoku as he embarks on his journey to reach the train. The remaining episodes will add approximately 70 new animation cuts and new background music.
All 7 episodes will be available starting October 10th on Funimation and Crunchyroll.

Therefore, Funimation will stream the new anime season as soon as it premieres this year. Official Website.
Synopsis:
Since ancient times, rumors abound of man-eating demons lurking in the forest. Because of this, the locals never venture outside at night. Legend says that a demon slayer also roams the night, hunting these bloodthirsty demons. For young Tanjirou, these rumors will soon become his harsh reality… Since his father's death, Tanjirou has taken on the responsibility of supporting his family. Although their lives may be hardened by tragedy, they have found happiness. But this fleeting warmth is shattered one day when Tanjirou finds his family slaughtered and the only survivor, his sister Nezuko, transformed into a demon. To his surprise, however, Nezuko still shows signs of human emotion and thought… Thus begins Tanjirou's quest to fight demons and turn his sister human again
Finally, the first season of Kimetsu no Yaiba premiered in April 2019.
