Old



Old is a world type exclusive to the Bedrock Edition. The purpose of this world type is to provide smaller worlds on older or low-end devices that do not perform well with infinite worlds.

Creation
To create an Old world, simply select the "Old" type in the World Type drop down of the world creation screen. Optionally, on low-end devices, toggle "Limited worlds" in the Video section of the options screen.

Overworld
Old worlds consist of a finite map with an area of 256×256 blocks with 128 maximum block height.

Biomes that cannot be generated in this world type:

However, as a result of their limited size, only a few biomes can be generated per world. Also, biomes that generate in here are shrunken 4× (16× area) to allow more biomes to generate. When creating an Old world, the player always spawns in the middle of the world. If starter map is enabled, the map is in scale level $1/4$ rather than of $3/4$.

Because of the player always spawning in the middle of the world, the center of the world is very rarely at 0,0, meaning the game generates the full world in order to find a valid spawnpoint, then it limits the world to 256×256. It is possible, through NBT editing, to move the center of an old world to another area in the seed.

Structures that can generate in the Overworld in this world type are:
 * Villages, sometimes generated at the border that gets cut off by the border, resulting village without any meeting point, only one house, or a jobsite building, or even just a road.
 * Lakes can still generate normally, but lava lakes do not generate near bedrock. Also, lakes do not generate under Y=10, due to ground completely solid.
 * Other generated structures, such as mineshafts, ocean monuments, woodland mansions, strongholds, dungeons, desert pyramids, jungle pyramids, swamp huts igloos, underwater ruins, and shipwreck never generate, making resources very limited.


 * Unlocking the last tier of cartographer villagers causes the game to stop ticking.
 * Obtaining an explorer map from commands causes extreme glitching, which may cause a crash.
 * Feeding a dolphin causes it to try to swim outside the world border.


 * Only double tall grass and large ferns can generate. Due to normal grass and fern not generating, savannas are less grassy.
 * Caves and ravines do not generate in this world type, making the underground area solid. Rarely, hollow areas generate.
 * With this world type, the Overworld is the only dimension that generates. Attempting to go to other dimensions results in the portal not being activated.
 * On very rare occasions, buried treasure and a desert well can generate in Old world types.

Due to the structure limitation in this world type, many resources become unobtainable in survival, and some mobs cannot spawn naturally.

Because of that, playing survival in this world type is challenging, due to the structure limitation reducing resources and also affecting mob spawning.

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

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

Both Nether and End are also bordered with the size 256×128×256. The Nether still generates normally, but the 8:1 travel ratio is 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 is generated, it is most likely be cut down by the world border. Despite nether portals not being able to be activated, returning from the Nether to the Overworld causes 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 generates only the central island without the outer islands. Sometimes the end fountain does not generate and the ender dragon sometimes gets stuck at the border. End gateway portals also don'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 act is impossible in Minecraft China.