Début juillet probablement.
It’s going to be ready this summer (most likely July) and we’re planning to make it available for free to players that already own Blood & Burning for Attila. We’ll release more details on it closer to the time, along with a more general update on future plans for the game.
Source : https://www.totalwar.com/blog/what-the-teams-are-working-on-june-2018