Slimefun Legacy 4.1.55 - *aka 4.1.52-4.1.54 Hotfix! *

Slimefun Legacy 4.1.55 combines the urgent item-model/storage recovery work with the standalone JustEnoughGuide handoff and verified proxy-forwarding support work for modern Velocity deployments. Item-model recovery

Some upgraded servers ended up with Slimefun items using newly assigned CustomModelData while older copies of the same Slimefun items had no model data. That metadata difference can prevent otherwise identical items from stacking and can break strict item comparisons used by machines, storage systems, FastMachines, and other addons.

4.1.55 includes an operator-controlled recovery path.

For servers that passed through the v4.1.52 forced hosted-pack migration, start with the guarded rollback audit:

/sf doctor item-models rollback-v52

/sf doctor item-models rollback-v52 confirm

The rollback resets only mappings that still exactly match Slimefun Legacy's bundled hosted-pack values. Custom/non-matching model values are preserved. After confirming the rollback, stop the server normally and restart before scanning stored items.

After restart:

/sf doctor item-models scan

/sf doctor item-models repair confirm

The scan is read-only. The repair only changes a stack when all of the following are true:

the item has a currently registered Slimefun ID;
that ID is currently configured as 0 in plugins/Slimefun/item-models.yml;
the stack's first modern CustomModelData float exactly matches Slimefun Legacy's bundled model value for that same ID.

When eligible, Doctor removes only Slimefun Legacy's bundled first model float. Additional model floats, flags, strings, colors, Slimefun PDC data, lore, enchantments, storage identity, and other functional metadata are preserved. If the bundled float was the only custom-model-data content, the component is removed completely so the repaired item can match pre-model-map stacks again. Storage and machine coverage

The explicit item-model Doctor traversal covers:

online player inventories and ender chests;
all Slimefun database backpacks, including ones not currently open;
loaded vanilla container inventories;
loaded Slimefun machine and BlockMenu inventories;
loaded Slimefun universal-data inventories;
dropped item entities;
bundles and nested container ItemStacks with bounded recursion.

Doctor does not force-load unloaded world chunks. Physical chests or machines in unloaded chunks can be repaired after those chunks are loaded and the command is run again.

Placed Slimefun machine identity is not rewritten. The recovery targets the affected ItemStacks and current model mapping, avoiding unsafe changes to persisted block IDs. Resource-pack configuration warning

The optional resource-pack section in configSFLAddons.yml now tells existing server owners to run /sf doctor item-models scan before enabling the pack. Servers whose storage/machine matching broke after v4.1.52 are directed to /sf doctor item-models rollback-v52 first. Safely adopting the resource pack on an existing server

Enabling the optional pack sender no longer changes item identity. Existing servers that deliberately want to adopt the bundled Legacy models now use:

/sf doctor item-models enable-pack scan

/sf doctor item-models enable-pack confirm

The scan is read-only. The confirmed adoption promotes only currently-zero mappings to their exact bundled values, preserves custom non-zero mappings, and updates reachable stored Slimefun ItemStacks only when their first model-float slot is empty. A different existing first float is reported as a conflict and left untouched. Other CustomModelData lanes and Slimefun functional metadata remain preserved.

After the confirmed traversal completes, wait for pending Doctor database writes to reach zero, stop normally, and restart before reopening to players. Run /sf doctor item-models enable-pack scan again after restart to verify the reachable migration is clean.

Server-owner recovery workflow

Before running the repair:

Stop the server and make a full backup.
Start the refreshed Slimefun Legacy 4.1.55 build.
Run /sf doctor item-models rollback-v52.
If Doctor reports exact bundled mappings and the server's storage/machine matching broke after v4.1.52, run /sf doctor item-models rollback-v52 confirm.
Check /sf doctor status, allow pending database writes to return to zero, then stop the server normally.
Restart with the same refreshed 4.1.55 build so registered Slimefun item templates are rebuilt from the corrected mappings.
Run /sf doctor item-models scan and review the candidate counts.
Run /sf doctor item-models repair confirm.
Re-run /sf doctor scan; its Slimefun Doctor Next Steps section now tells the operator which specialized command owns anything still unresolved.

The rollback changes only item-model entries that exactly match Legacy's bundled v4.1.52 mapping. Custom/non-matching model values are preserved. After restart, item-model repair still requires an exact bundled first-float match before removing anything from a stored ItemStack. Versioned configSFLAddons.yml

The Legacy addons configuration now includes config-version: 1. The config version advances only when the config schema itself needs a migration; it is not tied to every Slimefun Legacy release.

Existing unversioned configs receive the new resource-pack safety guide once. The guide records the exact enable-pack scan / enable-pack confirm adoption sequence, the clean restart requirement, and the safe disable rule: turning the Legacy sender off does not rewrite item mappings or stored items. This prevents future plugin starts from repeatedly rewriting the owner's config just to refresh comments. Safety

This repair is never invoked by automatic Item Doctor join, pickup, inventory-open, or chunk-load listeners. It requires an explicit administrator command and confirmation.

A dedicated static safety verifier guards the rollback eligibility rules, preservation of unrelated modern CustomModelData lanes, bounded nested-container traversal, and separation from automatic Doctor behavior. Normal /sf doctor scan and /sf doctor repair confirm also print actionable next-step commands for specialized repair lanes. Standalone JustEnoughGuide ownership

4.1.55 includes the core-side contract for the maintained standalone SF_JustEnoughGuide addon.

SlimefunRegistry.registerSlimefunGuide(mode, guide) provides a supported addon-facing guide replacement API instead of requiring reflection into the private guide map.
compareAndSetSlimefunGuide(mode, expected, replacement) lets an addon restore the previous guide only when it still owns the active implementation, preventing a stale disable hook from overwriting a later guide integration.
Legacy's machine-recipe providers and hardened input-fill service remain initialized even when the native Enhanced Guide UI is not active.
When standalone JustEnoughGuide is installed, Legacy leaves its classic indexed guide registered as the safe fallback and lets the addon take guide ownership through the supported API.
SF_JustEnoughGuide is a required compatibility/runtime-smoke target and is included in the maintained addon bundle.

This is the finalized form of the work started in #220 and landed through the superseding guide-API work in #221. Velocity modern forwarding support

4.1.55 adds an explicit proxy support boundary instead of assuming that an offline-mode backend is safe merely because it starts.

/sf doctor proxy checks the Paper backend's forwarding configuration, including Velocity modern forwarding, the forwarding secret, conflicting Bungee-compatible forwarding, and unsafe offline-mode configurations.

While a player is connected through the proxy, operators can also run:

/sf doctor proxy player /sf doctor proxy player

The player view reports the Bukkit UUID, Slimefun profile-owner UUID, whether those UUIDs match, unlocked research count, backpack count, and optional research state.

The proxy CI now performs a real Minecraft 26.2 login through Velocity modern forwarding, verifies that the client UUID reaches Paper/Slimefun unchanged, unlocks a Slimefun research, disconnects, reconnects, and requires the same UUID and research state to persist. Velocity + Paper 26.3 continues to receive startup/configuration/network-path smoke coverage while 26.3 remains the candidate server line.

Waterfall remains a legacy/archived startup/configuration/status-passthrough compatibility target; the maintained and identity-persistence-tested proxy target is Velocity modern forwarding. Compatibility and validation

The maintained compatibility range remains:

Minecraft 1.21.11
Minecraft 26.1.x
Minecraft 26.2
Minecraft 26.3

Before merge, the recovery change passed the main Slimefun Legacy build, Runtime Gameplay Correctness, Paper 26.2 two-boot runtime smoke, Paper/Purpur 1.21.11 compatibility, Purpur/Folia/Leaf 26.2 runtime smoke, proxy runtime smoke, required-addon runtime smoke, and the Paper 26.2/26.3 full-stack smoke.

Please check https://github.com/wickidcow/Slimefun-Legacy/releases/tag/v4.1.55 for plugins with patches!

Addons Direct Link: https://github.com/wickidcow/Slimefun-Legacy/releases/download/v4.1.58/SF_Addons_1.21.11-26.3.zip