Project Zomboid 42.21 Stable Tackles Disappearing and Duplicate Zombies

Project Zomboid moved Build 42.21 to its Stable branch on September 28 after testing it in Unstable. The headline change concerns the population around you: The Indie Stone says it addressed major causes of duplicated zombies in multiplayer and disappearing zombies in both solo and multiplayer worlds.

A More Consistent Threat Between Visits

The disappearing-zombie problem could occur when a player left a chunk, one of the areas used to divide the game world, and later returned. The developer said these faults were especially noticeable with larger zombie populations. That makes the fixes particularly relevant to players who deliberately turn up the pressure.

Importantly, the release announcement does not declare every population issue solved. The studio identified remaining cases for a later update. Treat this as a substantial correction to specific behavior, not a guarantee that every unusual disappearance has the same cause.

XXL trees received visibility changes as well, including better cutaways around vehicles and adjustments so overhanging trees do not hide houses and furniture. The studio also restored the Lua methods loadstring and loadstream after further security investigation.

Build 42.21 Changes

Smaller Fixes Reach Everyday Survival

The full 42.21 changelog goes beyond population management. It lists a correction for a crash when removing a player-built wall in an enclosed room, and a fix for player-built campfires colliding with vehicles.

Split-screen players get a separate correction for a crash involving both local players travelling in the same moving vehicle. The notes also address controls after a gamepad disconnects. These are distinct situations, so a fix in one should not be mistaken for a universal multiplayer stability guarantee.

For an existing group, it is worth separating a world-state problem from an input or display problem when reporting what still happens. A precise account of the action before the fault is more useful than simply describing a save as broken.

Stable Follows a Testing Step

The Indie Stone says this is its intended release pattern: publish to Unstable, gather testing feedback, make further changes where necessary, then promote the update to Stable. The branch name tells you where a build sits in that process, not whether every mod has been checked.

Back up an important save before changing a modded setup, and check the versions used by both the server and its players. Restoring two scripting methods is not certification that every community mod now works.