 
<translate> Akụkụ dị mkpa maka ịza ajụjụ a bụ: Oge nke anọ malitere ikuku na Ọktọba 10, 2017, ma setịpụrụ maka usoro 23 na The CW ruo Mee 22, 2018. Ya mere, azịza ikpeazụ bụ Ọktoba 10, 2017. <eng> 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. 