ETS2 Mods on a Convoy Dedicated Server: Export, Upload and Match

Installing ETS2 mods for single-player means dropping .scs files into a folder. Running ETS2 mods on a Convoy dedicated server works differently. The server never loads a mod file. It reads one exported description of your map, DLCs and mod list, and every driver who joins has to match it. If you are still deciding between your own Convoy server and TruckersMP, ETS2 multiplayer: TruckersMP vs your own Convoy server compares them.

This guide covers that workflow on a GameServerKings Euro Truck Simulator 2 server. You build the mod list on your own PC, export it with export_server_packages, upload two files, and decide whether cosmetic mods should be optional. It also explains what your drivers see when they're missing a mod, and why map mods such as ProMods need extra care. Running American Truck Simulator instead? The workflow is the same, and ATS mods on a Convoy server covers it.

How mods work on an ETS2 dedicated server

SCS's dedicated server documentation is blunt about this: "Dedicated server does not require any additional DLC or mod data… It is not required to copy any additional files. As the dedicated server does not use the Steam Client, it cannot access the workshop."

The server loads two files instead:

Both are created in the game, not on the server, and they mirror whatever profile you had loaded when you exported them. If you export from a profile with 12 active mods, the session requires those 12 mods. Uploading .scs files to the server does nothing.

On GSK servers both files live in the server home folder the egg creates:

.local/share/Euro Truck Simulator 2/
├── server_config.sii
├── server_packages.sii
├── server_packages.dat
└── server.log.txt

When the server is first installed, the install script adds a default server_packages.sii and .dat if none exist. These are generic files with mod_list: 0, exported in December 2022 for the base Europe map. We haven't confirmed that a pair that old still loads on the current game version, so the reliable route for any server, modded or not, is to export your own pair from your game and upload it (steps below).

Step 1: Build the mod list in your own game

Use the same game version your server will run. GSK's ETS2 server updates itself through SteamCMD on every restart while the Auto update variable is 1, so it runs the current public release (1.61 at the time of writing). If you're on a Steam beta branch, switch back to the public version before exporting.

1. Install the mods you want. Steam Workshop mods download when you subscribe. Manual mods go in Documents\Euro Truck Simulator 2\mod.
2. Open the Mod Manager from the title screen and activate exactly the mods the server should require, in the load order you want. Leave out anything personal that other drivers shouldn't need.
3. Load the profile into the world. The map has to be loaded when you export.

Prefer Workshop mods where you can. SCS's Convoy mod window can send drivers straight to a missing Workshop mod. It can't do that for a mod from a third-party site, and it can't check which version of that mod the server expects.

Step 2: Export the server packages

The export command lives in the developer console, which is off by default.

1. Close the game and open config.cfg in Documents\Euro Truck Simulator 2\.
2. Set both variables to 1:

   uset g_console "1"
   uset g_developer "1"
   

3. Start the game, load your modded profile and wait until you're in the world.
4. Press ~ and run:

   export_server_packages
   

server_packages.sii and server_packages.dat now sit in Documents\Euro Truck Simulator 2\, next to config.cfg. SCS notes that these files "are NOT linked to your account in any way", so you can share them with a co-admin.

Open server_packages.sii in a text editor to confirm the export. Under mod_list you should see one entry per active mod. If it says mod_list: 0, the profile had no active mods.

Step 3: Upload the files to your GSK server

1. Stop the server in the panel.
2. Open Files and go to .local/share/Euro Truck Simulator 2/.
3. Upload both server_packages.sii and server_packages.dat, overwriting the old ones. Always upload the pair together, because the .dat belongs to the .sii it was exported with. For large files, SFTP is more reliable than the browser upload.
4. Start the server. Once the console shows [MP] State: running, the session is up with your mod list.

A reinstall won't undo this. The install script only downloads the default packages when the files are missing. To go back to vanilla, export again from an unmodded profile and upload that pair.

If the console shows Server packages file not found, the files are in the wrong folder or have the wrong names. Check server.log.txt in the same folder for the full error.

Step 4: Decide which mods are optional

By default every mod in the export is mandatory. SCS lets mod authors mark a mod as multiplayer-optional with mp_mod_optional: true in its manifest.sii. That suits things like UI, sound or graphics tweaks that don't change what other drivers experience. Three conditions all have to hold:

• The mod's author set mp_mod_optional: true. You can't add this for someone else's mod without editing it.
• Your server allows it. In server_config.sii set:

  mods_optioning: true
  

  SCS's description: "Flag to enable mods marked as optional, to be really optional." With it false, which is the default, every exported mod is required.
• Each driver allows servers with optional mods in their session browser filter.

Map mods ignore mp_mod_optional. They are always required.

server_config.sii is safe to edit for this, but four of its lines are rewritten by the panel on every boot: connection_dedicated_port, query_dedicated_port, server_logon_token and lobby_name. Change the lobby name and Steam token in the Startup tab (Lobby name, Steam Auth token), not in the file.

What drivers see when they join

When a driver selects a modded session they're missing mods for, the game opens SCS's mod synchronisation window. Their installed mods are on the left and the server's mods are on the right. Missing Workshop mods can be subscribed to through the in-game Steam overlay. Anything from a third-party site has to be downloaded by the driver. The Confirm button unlocks only when everything matches.

Things to tell your drivers before the first drive:

• Match the game version. SCS's session browser blocks joins on a different game version. Players on an open beta branch won't get in while the server is on the public release.
• Back up profiles. SCS warned during the Convoy mod beta that modded sessions could corrupt profile saves in rare cases, so back up the profile folders in Documents\Euro Truck Simulator 2\ first.
• Sound mods are local. Other drivers hear default truck sounds. Truck, trailer and cargo mods need proper traffic models, or other players may not see them correctly.
• Post the mod list with download links, especially for non-Workshop mods. The game can't check versions for those, so everyone should use the same download.

Map mods and ProMods

Map mods are the hardest case. They can't be optional, and SCS warns that map compatibility can break between major game versions. A map mod that pins compatible_versions to 1.60 won't load on 1.61.

ProMods, the most popular of these, isn't on the Steam Workshop and publishes its own instructions for Convoy. Follow them for the ProMods version you're on. Then export from a profile where the whole map combination loads without errors. If the export works on your PC, the server can run it, because the server needs no map files of its own.

Keeping the server working after game updates

SCS ships a major ETS2 update every few months, and mods often lag behind. After an update:

1. Restart the server so Auto update pulls the new build.
2. Update your own mods and check that they still activate in the Mod Manager.
3. Re-export and re-upload the packages. SCS doesn't say whether packages exported on an older game version keep working after an update, so a fresh export from the updated game is the safe choice, and it's the first thing to try if drivers see a map or version mismatch.

Create a backup before any of this, so you can roll back to the previous working pair of files.

Troubleshooting

To make someone a session moderator, add their Steam ID to moderator_list in server_config.sii. Moderators can use /set_time HH:MM and /set_rain_factor 0-1 in chat. For more on the panel's Files and Startup tabs, see How to use your server panel.

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