Minecraft 26.4 snapshot 5

20 Oct 2026

TODO

These writeups assume you have read the Official Changelog before continuing.

Table of Contents

• Packed Ice Bricks
• Data Packs
  • Tags
• Debug Properties
• Mojang API

Packed Ice Bricks

Packed Ice Brick variants have 0.5 hardness and 0.5 blast resistance. They have the same friction as normal blocks.

The best tool for Packed Ice Bricks is a pickaxe. They drop when mined by hand or with any tool.

Packed Ice Bricks show up as #A0A0FF “Ice” on a map. When placed under a note block, they make the “Chime” instrument sound.

Data Packs

Tags

Only Packed Ice Bricks and Chiseled Packed Ice were added to the #ice block tag. Packed Ice slabs, stairs, and walls were not added to the #ice block tag.

Debug Properties

At runtime, the game generates a monomorphized form of some Java classes (currently only PolymorphicUpscaler) for optimization purposes. The new -DMC_DEBUG_DISABLE_RUNTIME_MONOMORPHIZATION debug property disables runtime generation, and -DMC_DEBUG_DUMP_RUNTIME_MONOMORPHIC_CLASSES outputs the generated .class files in the monomorphizer folder.

Removed -DMC_DEBUG_DISABLE_BELOW_ZERO_RETROGENERATION.

Mojang API

All requests now send the X-Client-Version header, set to the version’s name in version.json, such as “26.4 Snapshot 5”.