 
 <translate> The important part for answering this question is: The fourth season began airing on October 10, 2017, and is set to run for 23 episodes on The CW until May 22, 2018.
So, the final answer is October 10 , 2017. <hau> Muhimmin bangare don amsa wannan tambayar shine: Lokacin na huɗu ya fara watsa shirye-shirye a ranar 10 ga Oktoba, 2017, kuma an saita shi don a gudanar da aukuwa 23 a The CW har zuwa 22 ga Mayu, 2018. Don haka, amsar karshe ita ce 10 ga Oktoba, 2017. 