Old



Old was a world type exclusive to and. The purpose of this world type was to provide smaller worlds on older or low-end devices that did not perform well with infinite worlds.

Creation
To create an Old world, all the player had to do was select the "Old" type in the World Type drop-down of the world creation screen. Optionally, on low-end devices, the player could toggle "Limited worlds" in the Video section of the options screen. This sometimes failed due to limited access.

Overworld
Old worlds consisted of a finite map with an area of 256×256 blocks with 128 maximum block height, but could be expanded in area using a NBT editor by changing the LimitedWorldDepth and LimitedWorldWidth values.

Biomes that could not be generated in this world type:

However, as a result of their limited size, only a few biomes could be generated per world. In addition, since dark forests did not generate, areas of specific lush biomes were shuffled slightly, compared to their placements in default worlds. Also, biomes that were generated here were shrunken 4× (16× area) to allow more biomes to generate. Due to this shrinking, a seed generated different terrain in an old world than in an infinite world, although with similar overall characteristics (for example, the "Island Survival" seed from seed templates put the player on an island in the middle of the world, but the resemblance ends there).

When creating an Old world, the player always spawned in the middle of the world. If the starter map was enabled, the map was in scale level $1/4$ rather than of $3/4$. Additionally, the player respawn radius during world creation or world edit could be up to 256 blocks, rather than up to 128 blocks as in flat and infinite.

The center of the world was rarely at 0,0, meaning the game generated the full world in order to find a valid spawn point, then it limited the world to 256×256 around that point, so the center of the world was the coordinate of that spawn point. It was possible, through NBT editing, to move the center of an old-world to another area in the seed.

Some generated structures never appeared in the Old world type:
 * Mineshafts, ocean monuments, woodland mansions, strongholds, dungeons, desert pyramids, jungle pyramids, swamp huts, igloos, ocean ruins, shipwrecks, pillager outposts, and ruined portals do not generate, making resources limited.
 * Caves and canyons do not generate in this world type, making the underground area solid, although hollow areas occasionally appear.
 * Tall grass and ferns did not generate as part of any biomes, though they could generate as part of village structures. This made certain biomes such as plains and savannas less grassy. Grass only generated in bamboo jungles, while large ferns were generated normally.
 * Even with experimental gameplay enabled, the world height was 128 blocks, with the bottom layer at Y=0.

Other structures could generate in the Overworld:
 * With this world type, the Overworld was the only dimension that generates. Attempting to go to other dimensions resulted in the portal not being activated.
 * Villages sometimes generated near the world border and get cut off by it, resulting in a village without any meeting point, only one house, or a jobsite building, or even just a road.
 * Lakes could still generate normally, but lava lakes do not generate near bedrock. Also, lakes did not generate under Y=10, due to the ground being completely solid.
 * Desert wells rarely generated in this world type.
 * On rare occasions, buried treasure and fossils could generate.
 * New Mountains still generated with experimental gameplay enabled, but are cut off at Y=127, causing the top of them to become a flat plateau of stone. This usually happened if mountains generate past the meadow layer.

Some mechanics broke in this world type:
 * Unlocking the last tier of cartographer villagers caused the game to stop ticking.
 * If the player obtained an ocean explorer map or a treasure map from commands, any explored areas outside the world border were completely black. If the player attempted to get a woodland explorer map, the game stopped ticking for about 100 seconds, and an error message was eventually given.
 * Feeding a dolphin caused it to try to swim outside the world border.

Due to the structure limitations in this world type, many resources became unobtainable in survival, and some mobs could not spawn naturally.

Because of that, playing survival in this world type was challenging, due to the structure limitations reducing resources and also affecting mob spawning. While water and lava always generate in this world type, lava usually does not on the surface, although it always does, underground and always directly in contact with, the invisible bedrock in extremely small patches of 1×1 block. If the Overworld didn't generate lava, then cobblestone would become non-renewable without going to the Nether.

Nether and End
In Old worlds, the Nether and the End could not be accessed unless the world was converted to the Infinite type, as detailed below.

However, the Nether and End actually existed in this world type but the only way to access these dimensions was via command or  with the corresponding portal, just like the Overworld.

Both Nether and End were also bordered with the size 256×128×256. The Nether still generated normally, but the 8:1 travel ratio was maintained, meaning that returning to the Overworld may cause the player to become stuck (due to the Overworld being 256×128×256 in size).

If a nether fortress was generated, it is most likely going to be cut down by the world border. Despite nether portals not being able to be activated, returning from the Nether to the Overworld caused a newly activated Nether portal to generate in the overworld (this is due to nether portals not counting when placed with commands).

The End in Old worlds generated only the central island without the outer islands. Sometimes the end fountain did not generate and the Ender Dragon sometimes got stuck at the border. End gateway portals also didn't work.

Converting to infinite
To convert an Old world to an Infinite type, select the pencil icon next to the old world in the world selection screen, then select "Make Infinite!". This creates a new world with all of the saved data (inventory, terrain, structures, etc.) of the old world, sets the world type to Infinite, and keeps the world name; the old world is then renamed.

After converting to Infinite, the terrain copied from the old world has a terrain wall separating it from the added area, as infinite worlds generate larger biomes.

This process is not available in Minecraft China.