Installation and Upgrades

📦 Installation & Upgrades

Slimefun Legacy is maintained for modern Paper servers and should be installed like a production plugin: backup first, stage changes, restart cleanly, then validate.

Requirements

Component	Current Legacy target
Server	Paper 26.2 / Minecraft 26.2
Purpur	Supported when based on the same Paper line
Java runtime	Java 25
Folia	Experimental secondary target
Client mod	Not required
Resource pack	Optional; server-provided if used

Spigot/CraftBukkit, Sponge, hybrid mod/plugin servers and Fabric/Forge/NeoForge are not supported runtime targets for Slimefun Legacy.

Fresh installation

1. Stop the server normally.
2. Create a complete backup.
3. Download a tested JAR from the Slimefun Legacy Releases page.
4. Place the JAR in plugins/.
5. Make sure there is only one Slimefun core provider in the plugins directory.
6. Start the server normally.
7. Review console startup for dependency or addon failures.
8. Run the validation commands below.

Warning

Do not use /reload to install, upgrade or repair Slimefun. Perform a full restart.

Upgrade checklist

Back up at minimum:

• worlds and player data;
• Slimefun data storage / data-storage where used;
• Slimefun plugin configuration;
• databases and storage data;
• addon plugin folders and addon data;
• the exact old JARs needed for rollback.

Then upgrade one layer at a time when practical: core first, validate, then addon changes.

Post-start validation

Run:

/sf doctor status
/sf doctor core
/sf doctor compatibility
/sf doctor dependencies
/sf doctor runtime
/sf doctor integrations

Then test representative gameplay:

• Guide/search;
• Enhanced Crafting Table and a multiblock;
• an electric machine;
• Cargo;
• backpacks/storage;
• protection integration;
• representative addon items and machines.

English-first configuration

For a normal English-only setup, Legacy recommends:

options:
  auto-update: false
  language: en
  enable-translations: false

Restart fully after changing these settings.

Migrating older items or translated data

Minecraft item stacks can retain old display names/lore. Slimefun Legacy includes conservative item/storage Doctor tools that identify recognized items by persistent Slimefun ID and avoid guessing unknown or ambiguous data.

Start with a dry run:

/sf doctor status
/sf doctor scan

Only after reviewing the results should an operator consider:

/sf doctor repair confirm

See Doctor & Diagnostics.

Rollback rule

If an upgrade causes serious problems, stop the server and restore both the previous plugin set and the matching backed-up data. Do not repeatedly swap core JARs against actively-mutating production data hoping the issue disappears.