[{"data":1,"prerenderedAt":30},["ShallowReactive",2],{"doc-en-switch-build-project-zomboid":3},{"path":4,"slug":5,"title":6,"description":7,"category":8,"subcategory":9,"icon":10,"date":11,"author":12,"order":13,"image":14,"tags":15,"keywords":20,"docGroup":27,"docGroupIcon":27,"link_fr":28,"bodyHtml":29},"\u002Fdocs\u002Fen\u002Fgaming\u002Fproject-zomboid\u002Fswitch-build-project-zomboid","switch-build-project-zomboid","How to Switch Your Project Zomboid Server to Build 41 or Build 42","Run your Winheberg Project Zomboid server on Build 41 or Build 42 with the Steam Beta Branch variable of the panel, without losing your settings.","jeux","project-zomboid","tabler:file-text","2026-11-01","Winheberg",126,"\u002Fstatics\u002Fimages\u002Fdocs\u002Fen\u002Fgaming\u002Fproject-zomboid\u002Fswitch-build-project-zomboid.webp",[9,16,17,18,19],"build-41","build-42","version","gaming",[21,22,23,24,25,26],"project zomboid build 41","project zomboid build 42","legacy41","change project zomboid version","steam beta branch","project zomboid server","","\u002Fdocs\u002Fproject-zomboid\u002Fchanger-build-project-zomboid","\u003Ch2>Context\u003C\u002Fh2>\n\u003Cp>Project Zomboid now comes in two major versions. Build 42 is the main branch, installed by default on your \u003Ca href=\"https:\u002F\u002Fwinheberg.com\u002Fen\u002Fgaming\u002Fproject-zomboid\">Winheberg Project Zomboid server\u003C\u002Fa>. Build 41 is still available on Steam for communities that want to keep their habits or mods that have not been ported to Build 42 yet.\u003C\u002Fp>\n\u003Cp>The panel lets you pick the version installed on your server with a single variable. This guide shows you how to switch to Build 41, how to go back to Build 42 and how to handle your world, which is not compatible from one version to the other.\u003C\u002Fp>\n\u003Ch2>Prerequisites\u003C\u002Fh2>\n\u003Cul>\n\u003Cli>An active Project Zomboid server at Winheberg\u003C\u002Fli>\n\u003Cli>Access to the gaming panel \u003Ccode>https:\u002F\u002Fpanel.winheberg.com\u002F\u003C\u002Fcode>\u003C\u002Fli>\n\u003Cli>A recent backup of your server\u003C\u002Fli>\n\u003C\u002Ful>\n\u003Cdiv class=\"markdown-alert markdown-alert-caution\">\u003Cspan class=\"alert-icon\">\u003Csvg xmlns=\"http:\u002F\u002Fwww.w3.org\u002F2000\u002Fsvg\" width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\">\u003Ccircle cx=\"12\" cy=\"12\" r=\"10\"\u002F>\u003Cline x1=\"12\" y1=\"8\" x2=\"12\" y2=\"12\"\u002F>\u003Cline x1=\"12\" y1=\"16\" x2=\"12.01\" y2=\"16\"\u002F>\u003C\u002Fsvg>\u003C\u002Fspan>\u003Cdiv class=\"markdown-alert-body\">\u003Cp>A world created on Build 42 cannot be loaded on Build 41, and the other way around. Switching versions therefore means playing on another world. Back up your server from the \u003Cstrong>Backups\u003C\u002Fstrong> tab before anything else.\u003C\u002Fp>\n\u003C\u002Fdiv>\u003C\u002Fdiv>\n\u003Ch2>1. Stop the server and pick the branch\u003C\u002Fh2>\n\u003Col>\n\u003Cli>In the panel, stop the server with the \u003Cstrong>Stop\u003C\u002Fstrong> button.\u003C\u002Fli>\n\u003Cli>Open the \u003Cstrong>Startup\u003C\u002Fstrong> tab and find the \u003Cstrong>STEAM BETA BRANCH [REQUIRES REINSTALL]\u003C\u002Fstrong> variable.\u003C\u002Fli>\n\u003Cli>Enter the branch you want from the table below.\u003C\u002Fli>\n\u003C\u002Fol>\n\u003Ctable>\n\u003Cthead>\n\u003Ctr>\n\u003Cth>Desired version\u003C\u002Fth>\n\u003Cth>Variable value\u003C\u002Fth>\n\u003C\u002Ftr>\n\u003C\u002Fthead>\n\u003Ctbody>\u003Ctr>\n\u003Ctd>Build 41\u003C\u002Ftd>\n\u003Ctd>\u003Ccode>legacy41\u003C\u002Fcode>\u003C\u002Ftd>\n\u003C\u002Ftr>\n\u003Ctr>\n\u003Ctd>Build 42 (main branch)\u003C\u002Ftd>\n\u003Ctd>\u003Ccode>public\u003C\u002Fcode>\u003C\u002Ftd>\n\u003C\u002Ftr>\n\u003C\u002Ftbody>\u003C\u002Ftable>\n\u003Cimg src=\"\u002Fstatics\u002Fimages\u002Fdocs\u002Fen\u002Fgaming\u002Fproject-zomboid\u002Fswitch-build-project-zomboid-1793570473579-8461a67c7f0ff59d7ee79d7e.webp\" alt=\"STEAM BETA BRANCH variable set to legacy41 in the Startup tab\" width=\"372\" \u002F>\n\n\u003Cdiv class=\"markdown-alert markdown-alert-important\">\u003Cspan class=\"alert-icon\">\u003Csvg xmlns=\"http:\u002F\u002Fwww.w3.org\u002F2000\u002Fsvg\" width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\">\u003Cpath d=\"M12 22c5.523 0 10-4.477 10-10S17.523 2 12 2 2 6.477 2 12s4.477 10 10 10z\"\u002F>\u003Cpath d=\"M12 8v4\"\u002F>\u003Cpath d=\"M12 16h.01\"\u002F>\u003C\u002Fsvg>\u003C\u002Fspan>\u003Cdiv class=\"markdown-alert-body\">\u003Cp>To go back to Build 42, make sure to enter \u003Ccode>public\u003C\u002Fcode> rather than just emptying the field. Steam remembers the last installed branch, and an empty field reinstalls Build 41.\u003C\u002Fp>\n\u003C\u002Fdiv>\u003C\u002Fdiv>\n\u003Cdiv class=\"markdown-alert markdown-alert-note\">\u003Cspan class=\"alert-icon\">\u003Csvg xmlns=\"http:\u002F\u002Fwww.w3.org\u002F2000\u002Fsvg\" width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\">\u003Ccircle cx=\"12\" cy=\"12\" r=\"10\"\u002F>\u003Cline x1=\"12\" y1=\"16\" x2=\"12\" y2=\"12\"\u002F>\u003Cline x1=\"12\" y1=\"8\" x2=\"12.01\" y2=\"8\"\u002F>\u003C\u002Fsvg>\u003C\u002Fspan>\u003Cdiv class=\"markdown-alert-body\">\u003Cp>The variable description mentions \u003Ccode>b41multiplayer\u003C\u002Fcode> as an example. That is the old branch name, from the time Build 41 was itself in testing. Use \u003Ccode>legacy41\u003C\u002Fcode>.\u003C\u002Fp>\n\u003C\u002Fdiv>\u003C\u002Fdiv>\n\u003Ch2>2. Reinstall the server\u003C\u002Fh2>\n\u003Cp>As its name says, the variable only takes effect after a reinstall.\u003C\u002Fp>\n\u003Col>\n\u003Cli>Open the \u003Cstrong>Settings\u003C\u002Fstrong> tab.\u003C\u002Fli>\n\u003Cli>Click \u003Cstrong>Reinstall Server\u003C\u002Fstrong> then confirm with \u003Cstrong>Yes, reinstall server\u003C\u002Fstrong>.\u003C\u002Fli>\n\u003Cli>Wait during the \u003Cstrong>Running Installer\u003C\u002Fstrong> screen. The server downloads the chosen version from Steam, which takes from a few minutes to around twenty minutes.\u003C\u002Fli>\n\u003C\u002Fol>\n\u003Cp>The reinstall replaces the game files but keeps the \u003Ccode>.cache\u003C\u002Fcode> folder, which holds your settings (\u003Ccode>Pterodactyl.ini\u003C\u002Fcode>) and your worlds.\u003C\u002Fp>\n\u003Ch2>3. Start and check the version\u003C\u002Fh2>\n\u003Cp>Start the server with the \u003Cstrong>Start\u003C\u002Fstrong> button and open the \u003Cstrong>Console\u003C\u002Fstrong> tab. In the first lines, the server prints its version.\u003C\u002Fp>\n\u003Cpre>\u003Ccode class=\"language-bash\">version=41.78.21 demo=false\n\u003C\u002Fcode>\u003C\u002Fpre>\n\u003Cp>A version starting with \u003Ccode>41.\u003C\u002Fcode> confirms your server runs Build 41, a version starting with \u003Ccode>42.\u003C\u002Fcode> that it is on Build 42.\u003C\u002Fp>\n\u003Ch2>4. Start over on a compatible world\u003C\u002Fh2>\n\u003Cp>If a world from the other version is still there, the server refuses to load it and stops right away.\u003C\u002Fp>\n\u003Cpre>\u003Ccode class=\"language-bash\">The server savefile appears to be from a newer version of the game and cannot be loaded.\n\u003C\u002Fcode>\u003C\u002Fpre>\n\u003Cimg src=\"\u002Fstatics\u002Fimages\u002Fdocs\u002Fen\u002Fgaming\u002Fproject-zomboid\u002Fswitch-build-project-zomboid-1793571536395-04693ea5ebf3a21ef435ac00.webp\" alt=\"Console on Build 41.78.21 refusing a world created on Build 42\" width=\"738\" \u002F>\n\n\u003Cp>To start a new world without losing the old one, simply rename its folder.\u003C\u002Fp>\n\u003Col>\n\u003Cli>With the server stopped, open the \u003Cstrong>Files\u003C\u002Fstrong> tab and go to \u003Ccode>.cache\u002FSaves\u002FMultiplayer\u002F\u003C\u002Fcode>.\u003C\u002Fli>\n\u003Cli>Rename the folder named after your server, for example \u003Ccode>Pterodactyl\u003C\u002Fcode> to \u003Ccode>Pterodactyl_b42\u003C\u002Fcode>.\u003C\u002Fli>\n\u003Cli>Start the server. It generates a new world and the console shows \u003Ccode>*** SERVER STARTED ****\u003C\u002Fcode> once ready.\u003C\u002Fli>\n\u003C\u002Fol>\n\u003Cp>The day you return to the previous version, rename the current world (for example \u003Ccode>Pterodactyl\u003C\u002Fcode> to \u003Ccode>Pterodactyl_b41\u003C\u002Fcode>), then give the old folder its original name back, with the server stopped. The server reloads it as you left it.\u003C\u002Fp>\n\u003Ch2>5. Adapt your mods\u003C\u002Fh2>\n\u003Cp>Steam Workshop mods are published separately for each version. On a mod's Workshop page, the \u003Cstrong>Build 41\u003C\u002Fstrong> and \u003Cstrong>Build 42\u003C\u002Fstrong> tags show the supported versions. After a version switch, check every mod in your \u003Ccode>Mods=\u003C\u002Fcode> and \u003Ccode>WorkshopItems=\u003C\u002Fcode> lines and remove the incompatible ones.\u003C\u002Fp>\n\u003Cp>An incompatible mod can prevent the world from loading. The console then shows this message.\u003C\u002Fp>\n\u003Cpre>\u003Ccode class=\"language-bash\">zombie.world.WorldDictionaryException: World loading could not proceed, there are script load errors.\n\u003C\u002Fcode>\u003C\u002Fpre>\n\u003Cdiv class=\"markdown-alert markdown-alert-tip\">\u003Cspan class=\"alert-icon\">\u003Csvg xmlns=\"http:\u002F\u002Fwww.w3.org\u002F2000\u002Fsvg\" width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\">\u003Ccircle cx=\"12\" cy=\"12\" r=\"10\"\u002F>\u003Cpath d=\"M12 16v-4\"\u002F>\u003Cpath d=\"M12 8h.01\"\u002F>\u003C\u002Fsvg>\u003C\u002Fspan>\u003Cdiv class=\"markdown-alert-body\">\u003Cp>Our guide \u003Cstrong>How to Install Mods on Your Project Zomboid Server\u003C\u002Fstrong> covers mod setup and how to solve this error.\u003C\u002Fp>\n\u003C\u002Fdiv>\u003C\u002Fdiv>\n\u003Ch2>Need help?\u003C\u002Fh2>\n\u003Cp>If the server does not start after a version switch, our team can help. Open a ticket from your client area \u003Ccode>https:\u002F\u002Fbilling.winheberg.com\u003C\u002Fcode> with the \u003Cstrong>Technical\u003C\u002Fstrong> department, selecting your server in the \u003Cstrong>Related Product\u003C\u002Fstrong> field and stating the version you want.\u003C\u002Fp>\n\u003Cp>Good luck surviving, whatever your Build 🎮\u003C\u002Fp>\n",1794353874983]