Build 42 - What's New
Build 42 represents the biggest update in Project Zomboid's history, transforming core gameplay systems with animals, a complete crafting overhaul, revolutionary building mechanics, and countless quality-of-life improvements. After three years of development, Build 42 was released to the Unstable branch on December 17, 2024, with multiplayer support added in mid-December 2025.
This comprehensive guide covers everything you need to know about Build 42: what's new, how to access it, current limitations, server considerations, and what the future holds. Whether you're a veteran survivor or new to the Kentucky zombie apocalypse, this update fundamentally changes how you'll experience Project Zomboid.
Current Status and How to Access
Version Status (December 2025)
| Branch | Current Version | Status | Multiplayer |
|---|---|---|---|
| Stable | Build 41.78.16 | Production-ready | Full support |
| Unstable | Build 42.13.1+ | Beta testing | Available (recently added) |
Important: Build 42 remains in unstable/beta status as of December 2025. The stable branch is still Build 41. Based on Build 41's development timeline, expect 1-2 years before Build 42 reaches stable status.
How to Switch to Build 42 Unstable
For Steam (Singleplayer and Multiplayer):
- Right-click Project Zomboid in your Steam library
- Select Properties
- Navigate to the Betas tab
- From the dropdown, select "unstable - Unstable Build"
- Steam will automatically download Build 42
- Launch the game
For Dedicated Servers:
Server hosting varies by provider. Check with your host about Build 42 support. Many hosts now offer version selection in control panels, allowing you to choose between stable (Build 41) and unstable (Build 42) branches.
Warning: Save files are NOT compatible between Build 41 and Build 42. Backup your saves before switching branches!
Major Features and Changes
1. Animals and Animal Husbandry
For the first time in Project Zomboid's history, the world is alive with animals providing new survival opportunities and challenges.
Domestic Animals:
- Chickens - Provide eggs and meat; require feed and coop shelter
- Cows - Milk production and leather; require pasture space
- Sheep - Wool for crafting, meat; require shearing and grazing
- Pigs - Meat and hide; omnivorous, easier to feed
Wild Animals:
- Deer - Huntable for meat and hide
- Rabbits - Small game for trapping
- Rats - Environmental hazard, can be trapped
Animal Management Systems:
- Feeding schedules and nutrition management
- Health monitoring and veterinary care
- Breeding systems for sustainable livestock
- Shelter and pen construction requirements
- Resource harvesting (milk, eggs, wool, hide)
- Butchering and processing mechanics
Why It Matters: Animals provide renewable resources for long-term survival, reducing dependence on looting. However, they require ongoing care, feeding, and protection from zombies.
2. Crafting System Overhaul
The crafting system has been completely reimagined with tech trees, tiered machines, and unprecedented depth.
New Crafting Disciplines:
- Pottery - Clay collection, wheel throwing, kiln firing for containers and decorative items
- Metal Forging - Primitive to advanced metalworking, weapon and tool creation
- Stone Working - Quarrying, shaping, construction materials
- Brewing - Fermentation, distillation, alcohol production
- Leatherworking - Hide processing, armor and clothing creation
- Weapon Crafting - Melee weapon construction from raw materials
Crafting Machine Tiers:
| Tier | Type | Examples | Requirements |
|---|---|---|---|
| Primitive | Stone Age | Stone furnaces, basic kilns | Craftable with found materials |
| Intermediate | Medieval | Improved forges, wheels | Moderate skill and resources |
| Advanced | Electrical | Electric kilns, powered tools | Found only, requires power |
Skill Integration: New occupations and skills tie into the crafting system, allowing specialization in pottery, metallurgy, or other disciplines.
3. Revolutionary Building System
The most transformative change to base building since the game's inception.
Major Building Improvements:
- 32-Floor Height Limit - Build massive structures (up from 7 floors)
- Basements - Underground construction and naturally generated basements in existing buildings
- Improved Build UI - Intuitive interface for custom structure design
- Better Placement - Easier object rotation and positioning
- Expanded Building Options - More wall types, flooring, and decorative elements
Basement System:
- Randomly generated basements in homes and buildings
- Player-constructed basement excavation
- Excellent for secure storage and safehouses
- Natural temperature regulation
- Zombie-resistant when properly sealed
Build UI Enhancements:
- Preview mode shows structure before committing
- Snap-to-grid and alignment helpers
- Material requirements displayed upfront
- Undo functionality for mistakes
- Template system for repeating structures
4. Quality-of-Life UI Improvements
Hundreds of small improvements that collectively transform the gameplay experience.
Smart Interactions:
- Double-click bandages - Automatically apply to wounds
- Double-click literature - Start reading immediately
- Improved crafting menus - Better organization and search
- Context-aware actions - Fewer menu clicks for common tasks
Interface Polish:
- Cleaner inventory management
- Better item sorting and filters
- Improved health status displays
- Enhanced container management
- Streamlined cooking interface
5. Map Expansion and World Generation
Alexandria Years Support:
Servers can now run years into the future of the apocalypse, with the world adapting:
- Long-term building decay
- Vegetation overgrowth (similar to 10 Years Later mod)
- Weather and environmental changes
- Evolved gameplay dynamics
6. Additional Features
Gameplay Enhancements:
- New weather systems and seasons
- Expanded nutrition and cooking
- Improved AI behaviors
- Performance optimizations
- Bug fixes and stability improvements
What's Not Yet Included
Build 42 Unstable is incomplete compared to the planned final release:
Known Limitations (December 2025)
- Multiplayer instability - Recently added, still being tested
- Performance issues - Optimization ongoing
- Mod incompatibility - Most mods broken and awaiting updates
- Bugs and crashes - Expected in unstable branch
- Balance issues - Crafting and animal systems being tuned
- Missing content - Some planned features still in development
Features Still in Development
- Complete NPCs/storytelling system
- Additional animal types
- Expanded crafting recipes
- More building options
- Long-term balance adjustments
For Server Owners
Should You Update Your Server?
Consider these factors before switching your server to Build 42:
Reasons to Update:
- Access to all new features
- Player demand for new content
- Testing for eventual stable release
- Fresh gameplay experience
Reasons to Stay on Build 41:
- Stability and maturity
- Full mod compatibility
- Established player saves
- Proven server performance
- No save file compatibility between versions
Migration Considerations
Before Updating:
- Backup everything - World saves, configurations, mod files
- Announce to players - Give advance notice of downtime and save incompatibility
- Document current setup - Settings, mods, customizations
- Test on separate instance - Don't update live servers without testing
After Updating:
- Expect frequent restarts as patches release
- Monitor performance closely
- Be prepared to rollback if critical issues arise
- Communicate with players about bugs and limitations
- Wait for mod authors to update before re-adding mods
Dedicated Server Availability
Most hosting providers now support Build 42 Unstable, often with version selection in control panels. Check with your host about:
- Build 42 availability
- Version switching process
- Backup and rollback procedures
- Performance requirements (may be higher than Build 41)
For Mod Users and Creators
Mod Compatibility
Current Situation: Build 42 breaks almost all Build 41 mods due to fundamental code changes.
Mod Status:
- Most popular mods being updated by authors
- Process will take months as Build 42 stabilizes
- Some mods may be abandoned
- New mods being created specifically for Build 42
For Mod Authors:
- Major API changes require substantial rewrites
- Crafting system overhaul affects many mods
- New animal and building systems open new modding possibilities
- Check official modding forums for migration guides
For Players:
- Don't expect your favorite mods immediately
- Test mods in singleplayer before using on servers
- Report bugs to mod authors, not base game devs
- Be patient - mod updates take time
Frequently Asked Questions
Q: When will Build 42 be stable?
A: No official date has been announced. Based on Build 41's 2-year unstable period, expect 1-2 years of testing before Build 42 reaches stable. The Indie Stone prioritizes quality over speed.
Q: Can I play Build 42 with friends?
A: Yes! Multiplayer was added to Build 42 Unstable in mid-December 2025. However, expect bugs, crashes, and performance issues as it's still being stress-tested.
Q: Will my Build 41 save work in Build 42?
A: No. Save files are completely incompatible between versions. You must start fresh when switching to Build 42.
Q: Should I play Build 42 or stick with Build 41?
A: If you want stability, mods, and polished gameplay - stick with Build 41. If you want to experience cutting-edge features and don't mind bugs - try Build 42. You can switch back anytime.
Q: Do my favorite mods work on Build 42?
A: Almost certainly no, unless the mod author has specifically updated for Build 42. Check the Steam Workshop page for each mod.
Q: Is Build 42 more demanding on my PC?
A: Generally yes, especially with animals and expanded building. Optimization is ongoing, so performance will improve over time.
Q: Can I switch back to Build 41 after trying Build 42?
A: Yes, easily through Steam's beta tab. Your Build 41 saves will still be there (as long as you didn't delete them).
Q: What happens when Build 42 goes stable?
A: Eventually Build 42 will replace Build 41 as the default version. Build 41 may remain accessible as a legacy branch, but updates will cease.
Tips for Playing Build 42
Getting Started
- Expect bugs - Save frequently, report issues on forums
- Start small - Learn one new system at a time (animals OR crafting, not both immediately)
- Experiment - Many mechanics are new; trial and error is expected
- Read patch notes - Build 42 updates frequently with changes
Animal Husbandry Tips
- Start with chickens - easiest to maintain
- Build proper shelter before acquiring animals
- Stockpile animal feed early
- Protect pens from zombie hordes
- Learn butchering before you need it
Crafting Tips
- Prioritize primitive tier machines first
- Gather clay, stone, and metal early
- Choose one crafting discipline to master initially
- Advanced machines require power - plan accordingly
Building Tips
- Practice with the new UI in a safe area
- Basements are excellent for secure storage
- Consider vertical bases (32 floors available!)
- Use preview mode extensively before committing materials
Official Resources
- Official Project Zomboid Blog - Latest news and announcements
- Build 42 Wiki Page - Community-maintained information
- Steam Discussions - Community help and bug reports
- Official Forums - Developer interaction and support
Related Guides
- Top 8 Mods for Build 41 - While you wait for Build 42 mod updates
- Server Setup Guide - Setting up servers (Build 41 and 42)
- Server Logs and Troubleshooting - Debug Build 42 issues
- Sandbox Settings Guide - Customize your experience
Conclusion
Build 42 represents a monumental leap forward for Project Zomboid, introducing systems that fundamentally transform how you survive the zombie apocalypse. From caring for livestock to forging your own weapons, from excavating underground shelters to constructing massive skyscrapers, the possibilities have expanded exponentially.
While still in unstable status with ongoing bugs and missing features, Build 42 offers a glimpse into Project Zomboid's future - and that future is incredibly exciting. Whether you choose to dive into the unstable branch now or wait for stable release, understanding what Build 42 brings prepares you for the next evolution of this beloved survival game.
The journey from Build 41 to Build 42 isn't just an update - it's a transformation. Embrace the new systems, experiment with features, report bugs to help development, and most importantly: survive.