Installing Slimefun

Installing Slimefun Legacy

Slimefun Legacy is a server plugin. Players do not need to install a client mod.

Requirements

Requirement	Supported setup
Primary server	Paper 26.2 / Minecraft 26.2
Secondary server	Purpur based on Paper 26.2
Java runtime	Java 25
Client	Normal Minecraft Java client
Folia	Experimental

New installation

1. Stop the server normally.
2. Create a complete backup before changing the plugin stack.
3. Download a tested Slimefun Legacy build from the repository's Releases page.
4. Place the JAR in the server's plugins directory.
5. Make sure only one Slimefun core provider is present.
6. Start the server and review the complete startup log.
7. Run /sf doctor status and /sf doctor compatibility as an operator.
8. Test representative recipes, machines, backpacks, Cargo networks, protections and addon items before opening a production server.

Warning

Never use /reload to install, upgrade or repair Slimefun Legacy. Stop and start the server normally.

Upgrading from another Slimefun 4 build

Back up worlds, player data, Slimefun data, databases and addon data first. Remove or archive the previous core JAR so the server cannot load two competing Slimefun implementations.

For a fuller production migration checklist, see Installation & Upgrades.

Addons

Install Slimefun addons only after the core starts cleanly. See Addons and Compatibility & Addons before moving a large historical addon stack to a new server version.