ExtendedHeight 1.0.0

World height

• New worlds of the vanilla world types (Default, Superflat, Large Biomes, Amplified, Default_1_1) are buildable from y −256 to y 511.
• You can place and break blocks at any height in that range: below the bedrock and above the old y 255 limit.
• Existing worlds keep the height they were created with. Old 0–255 worlds stay vanilla and are saved in the vanilla format.
• The Nether and the End are unchanged.

Gameplay below y 0 and above y 255

• Hostile mobs spawn naturally in dark rooms below y 0, under the normal vanilla rules: darkness, the mob cap, and at least 24 blocks from the player.
• Sand and gravel fall below y 0 and land on the block under them. Long falls no longer drop them as items.
• Dragon eggs teleport and fall correctly at any height.
• Pistons push and pull blocks below y 0 and above y 255.
• Water and lava flow at every height.
• Mobs find paths, follow you and walk through doors at every height.
• Players, mobs, items and minecarts don't take void damage at negative heights. The void starts below the new world bottom.
• You can swim up and jump out of water below y 0.
• Block light (torches, glowstone) and sunlight through openings work at every height. Sunlight reaches down a shaft below y 0.
• Snow and ice form at the new heights.
• Beds, leashes, dismounting, cats sitting, shearing and Eyes of Ender behave correctly at any height.

Visuals (client)

• In survival, darkness closes in below y 0, like near the vanilla void. Can be turned off with vanillaWorldVoidFog = false.
• Void particles appear below y 8, as in vanilla. Lower their amount with void.voidParticleIntensity (1.0 = default, 0 = none), or set void.voidParticlesFollowMinY = true to show them only near the world bottom (below minY + 8).
• F3 shows the correct coordinates and biome at every height.
• Extended worlds render at every height. Without Angelica, render distance there is limited to 16 chunks. Your setting isn't changed, and vanilla worlds have no limit. With Angelica there is no limit, and shaders work.

Multiplayer

• ✅Dedicated servers support extended worlds. Chunks and block changes at every height reach the clients.
• ✅A client without the mod, or with a different version, gets a clear message when it tries to join.
• ✅A client with the mod can still join vanilla servers.

Config (config/extendedheight.cfg)

• world.minY: lowest buildable y. Default −256, vanilla 0.
• world.maxHeight: build height limit. Default 512, vanilla 256.
• Set them to 0 and 256 for vanilla-height worlds. Changes apply to new worlds only.
• void.vanillaWorldVoidFog: darkness below y 0 in survival (default on).
• void.voidFog, void.voidParticleIntensity, void.voidParticlesFollowMinY: tune the void fog and particles.

For mod developers

• An API that lets a dimension or world type use any height range (y −512 to 1024 blocks in total).
• ExtendedChunkPrimer for generating whole chunk columns, IBiomeAtProvider for biomes by height, and IVoidEffectsProvider for a world's own void effects.

Known issues

• ❌ArchaicFix: set enablePhosphor=false.
• ❌Hodgepodge: set earlyChunkTileCoordinateCheck=false.
• ❌An extended world cannot be opened without the mod.