Install CoFH Core on your server

CoFH Core is the library behind Team CoFH's mods, including Thermal Foundation and the rest of the Thermal series. By itself it adds very little to the game. Its own description calls it a core library that also holds a number of optional gameplay tweaks, and it adds a /cofh command with several subcommands. You usually install it because another CoFH mod asks for it. This guide installs it on a Forge 1.20.1 server.

Checked against CoFH Core 11.0.2 on Forge 1.20.1, October 2026.

Pick the right build

Modrinth lists these files, all marked release:

• Minecraft 1.20.1: CoFH Core 11.0.2, published on 26 May 2024, for Forge and NeoForge.
• Older versions: 10.3.1 for 1.19.2 and 9.2.3 for 1.18.2, both Forge only. A 1.16.5 build is listed too.

Modrinth's page warns that wikis about CoFH Core can be out of date, because the mod and its dependencies have changed between versions.

To change loader or version, open JAR Manager under More, choose Forge under Server software and 1.20.1 under Minecraft version, then press Apply change. The panel picks the Java version for you. The switch reinstalls the server and keeps your world, so make a backup in the Backups tab first. Change your Minecraft version or mod loader has the full steps.

Install it

1. Open Mods under Content and keep the Modrinth chip selected in the source chip row at the top of the tab. The Game version filter starts on your server's version.
2. Search for CoFH Core and press Install on CoFH Core. Modrinth lists no required dependencies, so no extra prompt appears.
3. Restart from the Console tab. The install toast says "Restart the server to load it".

Open the Installed view to check. CoFH Core should be listed with no Failed to load badge. To add a mod that needs it, such as Thermal Foundation, install CoFH Core first or let the "Needs 1 more add-on" prompt add it.

Players need it too

Modrinth lists CoFH Core as required on both the client and the server, so each player installs the same version for Forge 1.20.1. Join a modded server from your launcher covers the player side.

Commands

The project page lists /cofh COMMAND {PARAMS} subcommands, but it says that list describes the 1.18.2 build under active development. For 11.0.2 on Forge 1.20.1, the jar registers /cofh with these subcommands:

• crafting, enderchest, friend, heal, ignite, invis, invuln, recharge, repair and zap.
• invis and invuln take true or false, and ignite also takes a duration in whole numbers.
• heal, ignite, invis, invuln, recharge, repair and zap take targets. The jar's language file reports four of them as "Healed", "Supercharging", "Repaired equipment for" and "Zapped" followed by the target.
• The jar's CoreCommandConfig has a permission level setting for crafting, enderchest, heal, ignite and repair.

Type them in the Console tab, and name a player where a command takes a target.

Settings

The page names two config files. The client one is cofh_core-client.toml in the config folder. The server one is cofh_core-server.toml, which the server writes to the serverconfig folder of your world (no s; the page spells it serverconfigs). Your world folder is the one named by World folder in the Config Editor. Stop the server before you edit it in the File Manager, then start it again.

Common problems

• A CoFH mod stops at startup: CoFH Core is missing or the wrong version. Thermal Foundation 11.0.6 asks for CoFH Core 11.0.2 up to, but not including, 11.1.0.
• A player cannot join: a different CoFH Core version on their side can cause this. Fix the mismatched mod channel list error explains the message.
• Other crashes: Fix mod and plugin errors on Minecraft covers reading the Console log.