The Outbreak update for The Last Stand: Dead Zone was released on May 24, 2018. It introduced a new Criminal zombie type, as well as new prison-improvised weapons, prison-themed clothing, and riot gear.
"The generators at the prisons finally gave out. The worst of the worst are out and they are hungry.
Stored and stashed are plans for improvised weapons made by prisoners. Riot gear used by the Union City Department of Corrections is also being found.