Source: Monogatari Series anime’s website, Sword Art Online: Alicization anime’s website and Twitter account via Yaraon!
The Twitter account or the Sword Art Online: Alicization anime revealed on Sunday that the episode airing next week will be an “episode 18.5” recap episode.
Currently, Sword Art Online: Alicization airs on those four channels on Saturdays at 24:00.
The official website for the Monogatari Series anime franchise revealed on February 6 that the “Zoku Owarimonogatari & Monogatari Series Selection” program will premiere on Tokyo MX, Gunma TV, Tochigi TV, and BS11 on April 6 at 24:00 (effectively April 7 at 12:00 a.m.), and will air on Saturdays in that same time slot.