Detailed Primers

These chapters preserve the upstream primer content step by step. Each section heading links directly to that section within the primer page.

1.21.1 -> 1.21.2/3

Full primer

• Pack Changes
• The Holder Set Transition
• Gui Render Types
• Shader Rewrites
• Entity Render States
• Equipments and Items, Models and All
• Armor Materials, Equipment, and Model (Textures)
• Interaction Results
• Instruments, the Datapack Edition
• Trial Spawner Configurations, now in Datapack Form
• Recipe Providers, the ‘not actually’ of Data Providers
• The Ingredient Shift
• BlockEntityTypes Privatized!
• Consumables
• Registry Objcet Id, in the Properties?
• Properties Changes
• Recipes, now in Registry format
• Minor Migrations

1.21.2/3 -> 1.21.4

Full primer

• Pack Changes
• Client Items
• Mob Replacing Current Items
• Particles, rendered through Render Types
• Minor Migrations

1.21.4 -> 1.21.5

Full primer

• Pack Changes
• Handling the Removal of Block Entities Properly
• Voxel Shape Helpers
• Weapons, Tools, and Armor: Removing the Redundancies
• Weighted List Rework
• Tickets
• The Game Test Overhaul
• Data Component Getters
• Tags and Parsing
• Saved Data, now with Types
• Render Pipeline Rework
• Model Rework
• Minor Migrations

1.21.5 -> 1.21.6

Full primer

• Pack Changes
• GUI Changes
• Waypoints
• Blaze3d Changes
• Tag Providers: Appender Rewrite
• Generic Encoding and Decoding: Replacing Direct NBT Access
• Server Player Changes
• Minor Migrations

1.21.6 -> 1.21.7

Full primer

• Pack Changes
• Minor Migrations

1.21.7 -> 1.21.8

Full primer

• Pack Changes
• Minor Migrations

1.21.8 -> 1.21.9

Full primer

• Pack Changes
• The Debugging Overhaul
• Debug Screens
• Feature Submissions: The Movie
• The Font Glyph Pipeline
• The JSON-RPC Management Servers
• Input Handling Consolidation
• Level#isClientSide now private
• Minor Migrations

1.21.9 -> 1.21.10

Full primer

• Pack Changes
• Minor Migrations

1.21.10 -> 1.21.11

Full primer

• Pack Changes
• The Rename Shuffle
• Oh Hey, Another Rendering Rewrite
• Gizmos
• Permission Overhaul
• New Data Components
• The Timeline of Environment Attributes
• The Game Rule Shuffle
• Minor Migrations

1.21.11 -> 26.1

Full primer

• Pack Changes
• Java 25 and Deobfuscation
• Loot Type Unrolling
• Validation Overhaul
• Datapack Villager Trades
• Level#random field now protected
• Data Component Initializers
• Item Instances and Stack Templates
• Serializer Records and Recipe Info
• Dye Component
• World Clocks and Time Markers
• Splitting the Primary Level Data into Saved Data
• Even More Rendering Changes
• Minor Migrations