Before you start
Stop the server before backing up its world, database and configuration. Keep a separate copy labelled with the version used. As checked on 26 October 2026, the publisher announces 42.21 Stable; verify your server’s actual version instead of assuming it has already updated.
Identify Build 41 or Build 42
Build 41 and Build 42 are separate compatibility environments. A legacy branch may suit a community retaining older mods. Official release notes also describe incompatibilities between particular Build 42 releases. Match clients to the server and never assume an older world will migrate without loss. Preserve the previous environment so that rollback remains possible if the new release cannot load your save.
Record both kinds of identifier
A Workshop ID identifies a Steam publication; a Mod ID identifies a module loaded by the game. One publication can contain several modules and dependencies. Keep separate lists rather than treating the two identifiers as interchangeable. WorkshopItems=1234567890 illustrates the field’s shape only. That number is not a recommendation: use the author’s actual publication and module identifiers.
Use the panel’s Workshop selection
Choose compatible Workshop items and modules through the panel’s resources interface. The validated profile supplies WorkshopItems and Mods during startup. Mod ID syntax differs for Build 42; let the panel produce the format for the selected environment. Manual changes to those same fields in CubixServ.ini can be overwritten by the selected profile at the next startup. Keep your selection and configuration consistent.
Change Sandbox settings carefully
Configuration files follow the server name. CubixServ.ini and CubixServ_SandboxVars.lua correspond to the CubixServ name when it is in use; confirm the actual name first. Preserve Lua syntax and change one setting at a time. Zombie population, exploration and persistent data affect load. Some settings behave differently on an existing save than when generating a new world, so retain the original configuration for comparison.
Diagnose connection failures
Compare exact client and server versions before checking missing mods, dependencies and startup errors. Test a reduced mod set on a backup copy. Removing a mod directly from an active world can discard objects or damage dependent data. The publisher supports Lua modding; Java loaders and modifications do not have equivalent official support. A loader being available does not make it a supported server component.
Validate recovery and resource needs
Keep the world, database, Sandbox files and mod profile as one recovery set. Check initial logins and a subsequent save before reopening to everyone. For genuine resource pressure, inspect memory, CPU, zombie population and explored areas during a representative session. Player count alone does not predict the workload of a heavily modified persistent world. Preserve evidence of the change that caused a failure.
For your situation
| Situation | Next check |
|---|---|
| Different version | Align the client branch and version with the server before modifying world data. |
| Installed but inactive mod | Check the module’s Mod ID, dependencies and branch compatibility. |
| Failure after updating | Restore a coherent backup with its matching configuration and versions. |
Official sources
These documents describe the relevant protocols and software. Your service terms and configuration still need to be checked.