According to the Square Enix blog, Square Enix didn’t want to announce the release date for the episode until they finished the episode. However, in the spirit of Max’s birthday (Happy Birthday Max!), they announced they were aiming for an October 20th release date.
The post states that some things may change in the episode before October 20th, but the development team wants to be sure that the episode is as good as possible. Additionally, because the team is trying to make the episode the best it can be, the release date for “Polarized” may be pushed back to ensure the quality:
If the release date gets pushed back, we’ll be sure to let you guys know to keep you up to date.
Life is Strange episode 5 “Polarized” will be released for PlayStation 4, PlayStation 3, Xbox One, Xbox 360, and PC. The episode is $5 and the entire game, including all five episodes is $20.