The developers from the FNTASTIC domestic studio published a small FAQ in Discord, in which the players about The Day Before answered some questions. From there we learn that before the release of the game, the authors plan to conduct beta testing. It will be unknown, however, it will be open or closed, and nothing is said about the deadlines either.
However, given that The Day Before should take place on June 21 of this year, then it is clearly not long to wait for the beta test.
If you are not familiar with The Day Before, then this is the MMO score for survival, the setting of which will be the populated zombie post-apocalyptic America.