According to the recapped blog, first episode of new* Witcher series will come out on December 20th. Recapped has not provided any background for this claim, but it has been right before about Yennefer and Geralt role casting, so perhaps they are correct this time as well. Interestingly enough, December 20th is also when filming of the 2nd season is supposed to begin. If so, season 2 may be out by the end of 2021.
*Witcher was first filmed in early 2000’s in Poland, but the show was, how to put it, not that great