Java Edition 21w38a

21w38a is the second snapshot for Java Edition 1.18, released on September 23, 2021, which make tweaks and fixes bugs.

Any old world can not be opened in this version (even old worlds from 21w37a), but it can before 1.18 released.

General

 * Options
 * Added "Simulation Distance", a new slider.
 * Entities will not be updated outside of simulation distance.
 * Allows higher render distance with less CPU load.


 * Subtitles
 * Added a new subtitle for the crop sound of shears.


 * server.properties
 * Added.

Technical

 * Telemetry
 * Readded, previously a part of game until 2018.
 * Only implemented in world load event now.
 * Sent data when loading singleplayer world or connecting to multiplayer server.
 * Contains following information:
 * Launcher identifier
 * User identitifer (XUID)
 * Client session ID (changes on restart)
 * World session ID (changes per world load, to be reused for later events)
 * Game version
 * Operating system name and version
 * Java runtime version
 * If client or server is modded (same information as on crash logs)
 * Server type (single player, Realms or other)
 * Game mode

World generation

 * Ore distribution
 * Copper Ore now generates up to Y=95, and increased its amount.
 * Lapis Lazuli Ore now generates in blobs, like other ores, instead of spread out.

General

 * Sprinting
 * No longer reduced to walking when gently brushing your sleeve against a wall.

Technical

 * Performance
 * Now, various background tasks including world generation are executed on a background thread pool.
 * The size of the thread pool equals.
 * Maximum amount of threads is 255, instead of 7. This limit can be overridden by Java system property.