Minecraft Bedrock: Why Do My Add-ons Break After Updating to v26.0/v26.2? (2026 Fix)

Quick Answer

Your add-ons break after updating to Minecraft Bedrock v26.0/v26.2 (1.21.20+) because Mojang introduced breaking changes to the script engine (ES modules), entity component system, and biome system. Packs using legacy require() syntax, removed entity components (like minecraft:behavior.nearest_attackable_target), or old biome JSON formats will fail silently or spam errors. Update your pack manifests to min_engine_version: [1, 21, 20], migrate scripts to ES modules, and replace deprecated components.

What Changed in v26.0/v26.2 (July 2026)

• Script Engine → ES Modules: Legacy require() and module.exports are removed. All scripts must use import/export syntax.
• Entity Component Removals: Several AI and behavior components were renamed or removed (e.g., minecraft:behavior.nearest_attackable_target → minecraft:behavior.attack_players).
• Biome System Overhaul: Old biome JSON files using "minecraft:biome" root keys now require the new "minecraft:biome_template" format with climate parameters.
• Animation Controller Changes: scripts/animate now requires explicit state machine definitions; inline Molang in animations is stricter.
• Render Controller Updates: Geometry and material references must use new identifier formats (namespace:path).

Step-by-Step Fixes

1. Update manifest.json min_engine_version

Open your pack’s manifest.json and ensure the header includes:

"min_engine_version": [1, 21, 20]

Packs with lower versions will not load on v26.0+.

2. Migrate Scripts to ES Modules

Before (legacy – broken):

// main.js
const { world } = require("@minecraft/server");
module.exports = { init: () => { ... } };

After (ES modules – required):

// main.js
import { world, system } from "@minecraft/server";
export function init() { ... }

Also update manifest.json script entry to use type": "module":

"modules": [
  { "type": "script", "entry": "scripts/main.js", "language": "javascript" }
]

3. Fix Deprecated Entity Components

4. Update Biome JSON to New Template Format

Old format (broken):

{
  "minecraft:biome": {
    "components": { ... }
  }
}

New format (required):

{
  "minecraft:biome_template": {
    "climate": { "temperature": 0.5, "downfall": 0.5 },
    "components": { ... }
  }
}

Platform-Specific Notes

• Windows 10/11 (Store/Launcher): Auto-updates to v26.2 — test packs immediately after update.
• iOS/iPadOS: App Store update rolls out in waves; force-close Minecraft and reopen to trigger update check.
• Android: Google Play staged rollout — join beta program for early access to test packs.
• Nintendo Switch / Xbox / PS5: Console updates are mandatory; packs must be compatible at launch.
• Realms: Realms servers auto-update to v26.2 — all active worlds’ add-ons must be compatible or they’ll disable.

Debugging Script Errors

Check content_log.txt in com.mojang/ for:

[Error] Script module resolution failed: Cannot find module '@minecraft/server'
[Error] Component 'minecraft:behavior.nearest_attackable_target' not found
[Error] Biome template missing climate parameters

Each error maps directly to one of the fixes above.

Still Having Issues?

Compare your pack against the official bedrock-samples repo — Mojang maintains updated reference packs for v26.0+. Also see our guide: Fix .mcaddon Import Issues.

Updated for Minecraft Bedrock 1.21.20+ (v26.0/v26.2), July 2026.