Project Zomboid Build 42 Multiplayer Goes Live

Build 42 of Project Zomboid has entered multiplayer testing with the release of the unstable branch, and we're proud to have contributed the core multiplayer rework that makes it possible.

The headline change is the move to server-side player inventory. Previously, inventory state was held client-side, which made it straightforward for malicious players to spawn items and break the survival experience for entire servers. With inventory now validated and authorised on the server, that class of exploit is closed off at the architecture level.

Getting there required reworking the item, container, and crafting subsystems across a mature and complex codebase — not a small undertaking. The unstable branch is live for testing now, and we're continuing to iterate with The Indie Stone as feedback comes in from the community.

Alongside the inventory overhaul, Build 42.13.0 includes over 150 bug fixes, new timed-action animations, crafting menu improvements, and Java 25 support.