26.2 migration

Migration

Breaking changes only — things that make a JSON file that worked in one version behave differently or stop loading in the next. Everything additive lives in the CHANGELOG.

This page is incomplete. It currently covers 3.0.0, 1.7.0, 1.6.0, and the network protocol change in 1.3.0. Earlier-breaking changes need to be pulled out of the CHANGELOG.

3.0.0

Nothing in your JSON changes. No field was added, removed or renamed in the port to Minecraft 26.2. Copy your content folder across and it loads.

What does change is the jar, and none of it is optional:

• 3.0.0 runs on Minecraft 26.2 only. 1.7.0 will not load on it, and this will not load on 1.21.1. Keep the version that matches your game
• Java 25, up from Java 21. A server pinned to an older JDK refuses to start
• GeckoLib 5.5.3, JEI 30.25.0.177, Curios 16.0.0. The builds you were running alongside 1.7.0 do not load on 26.2

Two texture forms got shorter, and both still work

Chest, shulker and armour-layer references can now be written the way the game addresses them:

  "refs": {
-   "single": "minecraft:textures/entity/chest/normal.png"
+   "single": "minecraft:normal"
  }

  "armor_layers": {
-   "layer_1": "othermod:models/armor/diamond_layer_1"
+   "layer_1": "othermod:diamond"
  }

Both forms are read, and the long one resolves to exactly the same asset, so this is cleanup rather than a fix. Nothing breaks if you leave it alone.

1.7.0

Nothing to change. Packs written for 1.6.0 load unchanged.

texture.mode no longer does anything

  "texture": {
-   "mode": "reference",
    "refs": {
      "sword": "minecraft:item/netherite_sword"
    }
  }

What a value is now comes from the value itself: a : makes it another mod's asset, a file extension makes it a file in your folder. A pack that still declares mode works exactly as before — the field is read and ignored — so deleting it is cleanup, not a fix.

The one thing that genuinely changed: a pack declaring "mode": "default" and values in refs used to ignore those values and show the placeholder textures. Those values now apply. Nobody writes both on purpose, but if you did, remove the refs block rather than the mode line.

See Textures & Models for the full rule.

1.6.0

cooking_time is now in seconds

Applies to smelting, blasting, smoking and campfire_cooking.

- "cooking_time": 200
+ "cooking_time": 10

Divide your old value by 20. A file left untouched cooks 20× slower than intended — 200 used to be the vanilla furnace default and is now three and a half minutes.

Decimals are accepted, so "cooking_time": 7.5 is valid.

requires_player_kill now defaults to false

  "mob_drops": {
    "entities": ["all"],
    "chance": 0.10,
+   "requires_player_kill": true
  }

It used to default to true. If your drops back are a server economy, declare it explicitly — otherwise a fall-damage or lava farm prints currency with no player involved. The parser warns when the field is left undeclared.

The check also changed meaning: it now asks whether a player damaged the mob recently, not whether a player landed the killing blow. A mob finished off by its own fall after a player hit it still counts.

affected_by_looting replaced by looting_mode

- "affected_by_looting": true
+ "looting_mode": "count"

- "affected_by_looting": false
+ "looting_mode": "none"

The new third value, "chance", raises the drop probability instead of the amount — vanilla uses one or the other, never both on the same drop. Default is "count".

1.3.0

Network protocol

1.3.0 clients cannot join pre-1.3.0 servers, and vice versa. Both sides must update together. Nothing to change in your JSON files.