It's taken a year, but Project Zomboid multiplayer has finally opened its doors again, just in time for the holidays

Almost exactly a year after Project Zomboid build 42 first launched, developer The Indie Stone has given us an early gift for the holiday season by deploying its long-awaited multiplayer support. Any apocalypse survival expert worth their salt knows that having reliable companions is far more valuable to staying alive than any single resource or piece of equipment, so it's no surprise that the ability to run a multi-person server is one of the most popular ways to play the zombie game. It's been a long wait, but Project Zomboid build 42.13 has what you need, and it's live right now.

The new Project Zomboid 42.13 patch notes are just as big and beefy as we've come to expect, including everything from better target selection with firearms to improved interior lighting, better building, and a whole bunch of quality-of-life additions. Even if you're a pure solo-survival enthusiast, there's lots to dig through, but unquestionably the biggest deal is the ability to begin stress-testing multiplayer. Naturally, being an 'unstable' build, you can still expect some rough edges, but at least you'll be able to team up with your pals and attempt to hold off the hordes together over the festive period.

The wait for build 42 multiplayer might not have been quite as long as it was for build 41 veterans, but it's still a work in progress. The Indie Stone "strongly" advises anyone to only play via whitelisted servers or in Steam co-op, and says that it's "currently inadvisable to have more than 20 players on a server," although it's looking to improve this. Old saves prior to 42.13 are no longer compatible, and the conversion "will very likely break elements of your game," so be sure to make a backup before attempting it.

You'll also want to turn off all your Project Zomboid mods for the time being (yes, even client ones), and avoid using the debug tool while in an active multiplayer session. "Much has changed under the hood," The Indie Stone cautions, "please be patient with the modding community while they update to make their mods compatible." Ragdoll functionality has also been removed, but is planned to return in a later patch. The developer also warns that "future updates to the unstable branch will disrupt ongoing MP games."

As for what to watch out for across the rest of build 42.13, targeting with firearms will now prioritize the head first, followed by the spine, pelvis, and then other limbs. A range of items can now be equipped while walking, including the new-look 'satchel' slot that encompasses satchels, water bags, and cowboy canteens. Double-click functionality has been expanded for many items, so be sure to browse the full details to understand what's on offer.

Interior lighting gets a pass; you'll no longer see individual rooms darkened, and window blockers such as non-metal barricades and curtains will allow some light through, even if vision is blocked. There's a new 'motion sensitive' trait that makes you prone to getting sick during high-speed movement and turning. Elsewhere, more subcategories have been added to the crafting menu, foraging gets a distance bonus if you find items that are further apart, several traits have been rebalanced, and you can use chamomile, honey, or mint in hot drinks to boost flu recovery. Delicious.

Project Zomboid unstable build 42.13 is out now on Steam, including multiplayer support. It will be added to GOG once it is considered stable enough. In order to participate, you'll need to right-click the game in your Steam library, head to properties and then the betas tab, where you'll find the unstable build in the drop-down menu.