Masterful Machinery Upgraded

[1.21.1-0.1.1] - 2026-08-07 — Minecraft 1.21.1 / NeoForge port

Port of the 1.20.1 Forge codebase to Minecraft 1.21.1 on NeoForge, starting a fresh version line for this fork. Continues from 0.1.34.5-fix2 below; the version number restarts because this is a separately published fork, not a regression.

Requires NeoForge 21.1.0+ and Java 21.

Changed — read before updating a pack

• Mekanism chemical types are no longer distinct. Mekanism 1.21.1 merged gas, slurry, pigment and infusion into a single Chemical with no discriminator. All four port ids (mm:mekanism/gas, /slurry, /pigment, /infuse) still load and no pack file needs editing, but the distinction is now cosmetic: a port declared as gas will accept a pigment. Recipes relying on a gas port rejecting slurry no longer behave that way.
• Item nbt matching is narrower. 1.20.5 replaced the single item tag with typed data components; MM now matches against minecraft:custom_data. Existing items keep their data, but nbt that matched Damage or enchantments will not match, as those are separate components now.
• Botania support is disabled. Botania has no 1.21.1 release, so mm:botania/mana is not registered and recipes using it are skipped with a message naming the recipe. The port code is stubbed, not deleted.

Fixed

• A pack referencing a port from an uninstalled mod no longer makes the world unloadable. This previously surfaced as a NullPointerException during recipe parsing that killed world creation. Recipes and structures now parse independently — a failing one is logged with its id and skipped — and unknown port types report which types are registered.
• Datapack-supplied translation keys now work for port and controller names. The { "translation": "..." } form worked for structures but produced raw key text for blocks a pack registers.
• Port names no longer hardcode the English Input/Output suffix, so it translates with the rest of the name.
• The blueprint item's name is translatable. It was generated as hardcoded English and was the only item name no resource pack could override.
• StructureManager no longer carries an @EventBusSubscriber with no subscribers, which NeoForge rejects outright.

Notes

• Pack configs, datapacks, KubeJS scripts and existing worlds work unchanged. Machine, port, structure and recipe JSON is untouched, and the KubeJS builders keep the same signatures.
• Sample data now uses the c: common tag namespace instead of forge:, which NeoForge no longer provides.
• Verified: structure forming, recipe processing, item and energy ports, capabilities to and from other mods, GUIs, save/load, dedicated server, Jade, KubeJS. Not yet verified: fluid, Mekanism, PneumaticCraft and Create ports, blueprint pasting, JEI integration, and the debug tool, multiblock saver and priority setter.