Compatibility and Mods

Compatibility and Modding Guide

Project Zomboid Optimiser (PZO) is engineered for maximum coexistence with standard Steam Workshop mods, major community overhauls, and low-level Java modding frameworks.

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Game Version Support

Game Build	Client Support	Dedicated Server Support	Notes
Build 42 (Stable)	Full	Full	Full support for 32-thread simulation, chunk streaming, and Build 42 bytecode fixes.
Build 41 (Legacy)	Full	Full	Compatible with Build 41 Java 17 runtimes, networking tuners, and timer governors.

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ZombieBuddy Coexistence

PZO is 100% compatible with ZombieBuddy (zbNative and ZombieBuddy.jar):

• Preserved Native Agent: When running the PZO installer (install.bat / launcher), PZO scans ProjectZomboid64.json for "-agentlib:zbNative" or other custom agent flags and preserves them.
• Server Coexistence: On dedicated servers, PZOServerEngine.jar automatically checks for the presence of ZombieBuddy.jar in the server root and activates coexistence mode without conflicts.
• Complementary Execution: ZombieBuddy focuses on custom bytecode hooks and mod interfaces, while PZO optimizes hardware timers, Netty memory buffers, chunk streaming, and JIT compiler pacing. Both can run simultaneously with zero degradation.

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Java Mod Loader (JavaModLoader)

PZO includes an integrated Java Mod Loader that extends HotSpot Instrumentation access to third-party Java mods:

• Automatic Mod Discovery: On boot, PZO scans the game's mods/ directory and Steam Workshop content folders for .jar mod files.
• Runtime Instrumentation: Passes the JVM Instrumentation instance to third-party Java mods, allowing them to register their own bytecode transformers without needing to edit ProjectZomboid64.json individually.

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Overhaul & Popular Mod Compatibility

PZO does not alter game logic, item tables, or tile definitions, ensuring seamless operation with:

• NPC Mods: Fully compatible with Pat's NPC - Project Remnants (Build 42 SP), Superb Survivors, and custom AI frameworks. PZO's loop reduction and spatial caching directly improve NPC pathfinding performance.
• Vehicle & Map Expansions: Compatible with modded vehicles, trailers, and custom community maps (e.g. Raven Creek, Bedford Falls, Louisville expansions). Deep chunk caching prevents hitching when driving modded vehicles at high speeds.
• Animation & Clothing Mods: Compatible with custom character models, animations, and visual texture overhauls.

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Anti-Cheat Compatibility

• Non-Destructive Hooking: PZO operates strictly via standard Java Virtual Machine agent architecture (-javaagent). It does not modify game executable binaries (ProjectZomboid64.exe / ProjectZomboid64) on disk.
• Multiplayer Security: PZO is fully compatible with Project Zomboid's built-in server anti-cheat checksum verification.

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Mobile & Translation Layers (Zomdroid & Box64)

PZO is engineered to run reliably on ARM64 mobile devices running under box64 translation via Zomdroid:

• Safe SIMD Fallback: If box64 or the mobile processor does not support desktop x86_64 AVX2 vector instructions, PZO safely degrades to pure Java calculations without crashing.
• Driver Adaptability: If mobile OpenGL drivers (Turnip, Zink, ANGLE, GL4ES) lack desktop OpenGL 4.4 GL_ARB_buffer_storage, PZO dynamically reverts to standard vertex streaming.
• Mobile Resource Conservation: The Lua mod and Java engine eliminate excessive blood splats, corpse sound spam, and fog fragment fillrate math, significantly reducing mobile heat and thermal throttling.
• For complete mobile setup instructions, see the Zomdroid Support & Installation Guide.