The official website for the fourth season of Haikyu!! To The Top announced this Friday that the anime's production committee has decided to postpone the premiere of the second part of the fourth season. The committee cited considerations for preventative measures against the coronavirus ( COVID-19 ). The website will announce a new premiere date soon.

The second part of the anime, which includes episodes 14 through 25, was originally scheduled to premiere in July.
Synopsis:
Haikyuu tells the story of two students who enter the same school after facing each other years ago in a tournament. One of them is super talented and experienced, but arrogant and struggles to interact with his teammates. The other has vigor, talent, and incredible agility, but his lack of technique, experience, and height hinder him. Now they will have to evolve and work together to turn the currently failing high school volleyball team back into the champion it once was.
The first part of the anime was released on January 10th, and episode 13 aired on April 3rd. Crunchyroll streamed the first part of the anime as it aired in Japan.
The anime Haikyu!! was first released in April 2014, directed by Susumu Mitsunaka and written by Taku Kishimoto. However, the manga by author Haruichi Furudate has been published since February 2012 by Shueisha in Weekly Shonen Jump .
Source: ANN