The Indie Stone pushed Project Zomboid 42.21 to the stable branch on September 28, after a week in unstable beta. I’ve been waiting for this one, mostly because the zombie duplication bug has been a running joke on my usual server for weeks now.
What caught me first wasn’t the dupe fix, actually. It was the re-enabling of loadstring and loadstream. I don’t run a server, but I’ve watched modders tear their hair out over that change since 42.20.4. The apology in the announcement felt genuine, not like a PR line. That’s the kind of thing that matters when you’ve got a mod scene as deep as this game’s.
What 42.21 actually changes
The headline fixes are both about zombies behaving badly. The duplication bug in multiplayer and the chunk-despawn issue where zombies vanish after a player leaves and re-enters an area — those were most obvious on high-population servers. The devs say the game should be “much improved” but admit some instances remain on their radar for the next update.
XXL trees also got attention. They were blocking visibility when driving and hiding houses and furniture they overhung. The cutaway behavior now works better for vehicles, and overall transparency was adjusted. The team calls it a work in progress, so expect more tweaks later.
Then there’s the Lua methods. In 42.20.4, loadstring and loadstream were disabled to address security vulnerabilities. After further investigation, they’re back. The devs directly apologized to modders and server admins for the disruption.
They also thanked Scribl (Boris) and Rasmus Moorats (nnsee) for flagging the security issues that were fixed in 42.20.4.
What this means for players
If you’ve been on a server with more than a handful of players, you’ve probably seen the zombie duplication glitch. It turns a tense horde into a clown car of undead. The fix alone makes this patch worth grabbing. The chunk-despawn bug was more subtle but just as frustrating — you’d clear an area, drive away, come back, and it’s repopulated or empty when it shouldn’t be.
The XXL tree changes are a quality-of-life win, especially for anyone who drives a lot. I’ve clipped more than one tree that was hiding a house behind it. The transparency adjustment should help, though I’ll believe it fully when I stop hitting invisible branches.
For modders, this is a relief. The loadstring re-enable means a lot of scripts that broke in 42.20.4 can work again. Server admins who run custom Lua can stop holding their breath.
I’m not expecting this to be the last word on zombie bugs. The devs said as much. But for a stable release that went through a full unstable beta cycle, this feels like a solid step. The community didn’t report major issues during testing, and that’s a good sign for the new release process going forward.
