How to Change a Terraria World Difficulty on a Server

A Terraria world's difficulty (Classic, Expert, Master or Journey) is saved inside its .wld file when the world is created, so changing difficulty= in serverconfig.txt does nothing to a world that already exists. That line only applies when the server autocreates a new world. To change an existing world anyway, stop the server, back up the .wld file, and change its game mode with TEdit, or with /worldmode on a TShock server. Journey worlds can also move their enemy difficulty in game with the difficulty slider power.

What you can change on an existing world

How the server picks a difficulty

These lines in serverconfig.txt work together:

world=/path/to/Worlds/MyWorld.wld
autocreate=2
worldname=MyWorld
difficulty=1

The server looks for the file in world=. If it exists, the server loads it as it is, and autocreate, worldname, seed and difficulty are ignored. Only when the file does not exist does it create a new world with those values. difficulty takes 0 Classic, 1 Expert, 2 Master and 3 Journey.

That is the whole gotcha: people change difficulty=2, restart, and wonder why the boss fights feel the same. The server never looked at the line. Every key is in Terraria serverconfig.txt explained.

Step 1: Back up first

Stop the server and download the .wld and .wld.bak files. Changing the game mode outside the game is not something Terraria supports, so keep a clean copy you can upload again if anything looks wrong.

Step 2: Choose your method

Method A: New world on the right difficulty (cleanest)

1. Stop the server.
2. Set a new worldname= and a new world= path, plus difficulty= and autocreate= (1 small, 2 medium, 3 large).
3. Start the server. It creates the new world and keeps the old file untouched.

Your characters carry over, since they live on players' PCs, as long as they match the world type (Journey or not).

Method B: Change the existing world with TEdit

1. Download the .wld file to a PC.
2. Open it in TEdit, the community world editor.
3. In the world properties, change the game mode to Classic, Expert, Master or Journey.
4. Save, upload the file back over the old one, and start the server.

Use a TEdit release that supports your Terraria version, or the file may not load.

Method C: /worldmode on TShock

On a TShock server, an admin can run:

/worldmode expert

It accepts normal, expert, master and journey. Restart afterwards and test a fight. Some admins have reported on GitHub that the change did not behave as expected, so back up first and check enemies really hit harder.

Method D: Journey's difficulty slider

In a Journey world, players with access to the difficulty power can slide enemy strength up and down at any time, from easier than Classic to as hard as Master. On a server, journeypermission_setdifficulty in serverconfig.txt decides who can use it: 0 locks it for everyone, 2 allows everyone.

Journey worlds and characters must match

Journey characters can only join Journey worlds, and Classic, Mediumcore or Hardcore characters cannot join Journey worlds. If you switch a world to or from Journey, every player needs a character of the matching type, so tell your group before you change it. This catches out more groups than anything else on this page.

What happens to items and progress

• Expert and Master items stay in inventories and chests if you drop to Classic, including treasure bag drops and accessory slots already unlocked with a Demon Heart.
• Bosses already beaten stay beaten. The world remembers progress, not the mode it was beaten on.
• Hardmode stays on if the world was already in Hardmode.

Common problems

• Changed difficulty= but nothing happened: the world already exists, so the server ignored the line.
• The server made a brand new world: world= points at a path where no file exists, so autocreate kicked in. Fix the path.
• "Journey characters can only play Journey worlds": the world and character modes do not match after a change.
• TEdit file will not load on the server: the TEdit version is older than your server's Terraria version. Use your backup and a newer TEdit.
• Nobody can use the difficulty slider: journeypermission_setdifficulty=0.

Changing difficulty on GamezServers

On a GamezServers Terraria server running Vanilla or tModLoader, Difficulty and World name in Settings only shape a new world: the panel writes them into the config on every start, and the server uses them when no world of that name exists yet. To start a fresh world on another difficulty, pick the difficulty, enter a new world name and restart. The old world stays in the files (Vanilla keeps worlds in saves/Worlds/). The TShock type has no difficulty field, so use /worldmode there. To change the world you have, press Backup, Stop, download the .wld from the Files tab, edit it with TEdit and upload it back. You can also switch the server type to TShock for /worldmode, see TShock commands.

FAQ

Can you change a Terraria world from Classic to Expert?

Not in the game or with serverconfig.txt. Change the world's game mode with TEdit or /worldmode on TShock, or start a new Expert world.

Why does difficulty= in serverconfig.txt not work?

It only applies when the server creates a new world. If the world file in world= already exists, the line is ignored.

Can I change a Journey world to Master?

With TEdit, yes, but Journey characters then cannot join. Everyone needs a non Journey character for the changed world.

Does Hardmode count as a difficulty?

No. Hardmode is a stage of every world that starts when you defeat the Wall of Flesh, separate from Classic, Expert, Master or Journey.