Upgradable Gaps

Upgrade a golden apple into an enchanted golden apple. with 64 gold ingots. Everything in this mod is server-side: players will need nothing extra with the exception of very old Forge versions, see Installing), and it obviously works in single-player worlds too.

The Forge range skips the Minecraft versions Forge itself never shipped (1.16, 1.17, 1.20.5, 1.21.2 and so on).

The recipe

Place 8 gold ingots in each of the 8 outer slots of a crafting table, with a golden apple in the center. That is a total of 64 ingots plus the golden apple's 8: the same 72 ingots worth of gold as the old notch apple recipe.

Why this needs a mod instead of a data pack

Vanilla crafting cannot express "a stack of items in one slot". An Ingredient in recipe JSON has no count field, and the result slot removes exactly one item from every filled slot. A data pack recipe asking for gold ingots around a golden apple would cost 8 ingots, not 64, and there is no JSON knob that changes it.

So every build does the same two things: when the grid matches, it puts the enchanted apple in the result slot and sends it to the player; when the player takes it, it removes 8 ingots from each outer slot instead of one. How it hooks in depends on the platform:

• Mixin (Fabric, Quilt, NeoForge, Forge 1.15.2+, Ornithe): one mixin on the crafting menu's grid update and one on the result slot.
• JS coremods (Forge 1.13.2 - 1.15.1, which has no Mixin): the same two hooks, injected through Forge's own coremod system.
• A registered recipe plus crafting events (Forge 1.3.2 - 1.12.2): before 1.13 the server never sends its recipes to clients, so a real recipe is safe there.
• Inventory events (the plugin): it cancels the click on the result slot and does the craft itself.

On 1.13 and newer it registers nothing into any registry and adds no recipe serializer. That is what keeps vanilla clients able to join: since 1.13 the server sends every recipe to every client on login, and a vanilla client cannot decode a recipe type it doesn't have.

Installing

Drop the jar for your server and Minecraft version into mods/ (or plugins/ for the plugin) and restart. Jars are named upgradable-gaps-<version>+<platform>-mc<versions>.jar.

• Fabric / Quilt: any Fabric Loader 0.14+, or Quilt Loader. No Fabric API needed.
• Ornithe: install Fabric Loader with the Ornithe installer first; these jars do not run on Legacy Fabric.
• Forge 1.15.2 needs Forge 31.2.44 or newer (the first with Mixin).
• Forge 1.3.2 - 1.7.10: Forge servers this old turn vanilla clients away, so players need Forge installed. They do not need this mod.
• Forge 1.3.2 - 1.5.2 has one jar per Minecraft version: Forge that old loads mods by obfuscated names, which change with every release.
• Forge 1.7.2 only starts on Java 7; the one jar covers 1.7.2 and 1.7.10.
• NeoForge: any build for your Minecraft version.
• Plugin: one jar for every Bukkit-based server from 1.7.10 on, Folia included.

Things worth knowing

• Recipe book. The recipe doesn't appear in it, and that is a hard vanilla limit: the recipe book renders one item per slot with no count, and its click-to-fill places one item per slot. An entry would fill the grid with 8 ingots and then not craft, which is worse than no entry. It works fine arranged by hand -- you'll want to tell players about it.
• The vanilla golden apple recipe is untouched. Nothing overrides, removes or edits it, and this recipe cannot collide with it: its centre is a golden apple, not an apple.
• Batch crafting works. Stack golden apples in the centre and 8 ingots per apple in each outer slot, then shift-click the result to craft several at once.
• Crafters. The recipe does not work in a Crafter block. A Crafter consumes exactly one item per slot and resolves recipes through the recipe manager, which knows nothing about this pattern. That is deliberate -- letting it through would let a Crafter make notch apples for 8 ingots and a golden apple. Other auto-crafting mods will behave the same way, for the same reason.
• doLimitedCrafting. The recipe ignores that game rule and stays craftable, because there is no recipe entry for a player to unlock.
• Vanilla clients see a one-frame flicker of the input slots when crafting: their local prediction assumes one ingot per slot, and the server's correction arrives a tick later. Cosmetic only -- the server is authoritative.

Tuning the amount

INGOTS_PER_SLOT is the constant, in each source tree (Upgrade in modern/src/common, and its counterparts in ornithe/, forge-legacy/ and bukkit/). Both the match and the consumption read from it, so they stay in step. Change it everywhere and rebuild.

License

Copyright (c) 2026 Tyler Fursman. Licensed under the Mozilla Public License 2.0.