The creators of Atomic Heart have presented a new teaser for the fourth DLC, Calamity (or "Беда"):
The lull is coming to an end. A real storm is brewing. To challenge HRAZ, P-3 and the Twin will have to go to the most secret place of Enterprise 3826, where they will face a battle for the fate of the whole world.
Mundfish has not yet announced a release date, but has indicated the release window for the Atomic Heart DLC — spring 2026:
Calamity cannot be avoided: the final fourth DLC will conclude the story of the first part of Atomic Heart this spring!