While the Anniversary Edition itself is a free update for owners, the base game typically requires a purchase. However, there are official ways to access it at no cost: This War of Mine gets free anniversary DLC - PC Gamer
This update expands the original survival experience with several new additions: This War of Mine: Anniversary Edition Free Down...
: Encounter new non-playable characters (NPCs) that introduce fresh social dynamics . While the Anniversary Edition itself is a free
: Explore the Airport, Ghost House, and Port . This War of Mine: Anniversary Edition Free Down...
: Includes bug fixes, such as resolving a glitch where Day 42 would repeat endlessly . Legitimate Ways to Get the Game for Free