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 dropdown 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. They can generate with any of the current biomes except roofed forest, mushroom island, mega taiga, Extreme Hills +, mesa F, and birch forest M. However, as a result of their limited size, only a few biomes can be generated per world, also biomes generate in here are shrunken to allow more biome to generate. When creating this world, Player always spawn in the middle of world

Structures Which can generate in overworld in this world type are:
 * Villages, Only 2 variants of villages will generate, which are plains villages, and desert villages. Zombie Villages will never generate.
 * Lake can still can generate normally, but lava lakes will not generate near bedrock.Lakes will not generate under Y=60.60.
 * Other generated structures, such as Abandoned mineshafts, Ocean Monuments, Woodland Mansions, Strongholds, Dungeons, Desert temples, Jungle temples, Witch huts, and Igloos will not generate, Making resources very limited.
 * Caves and ravines will not generate in this world type, making the underground area solid. Rarely, hollow areas will generate.
 * With this world type, the Overworld will be the only dimension that will generate. Attempting to go to other dimensions will result in the portal not being lit.

Due to 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 will be challenging, due to the structures limitation reduces resources and also affect mobs 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 Nether and End actually exist in this world type but the only way to access these dimension is via command /setblock or /fill with coresponding portal.just like overworld,

Converting to Infinite
To convert an Old world to an Infinite type, tap on the pencil icon next to the old world in the world selection screen, then tap "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 will have a terrain wall separating it from the added area, as infinite worlds generate larger biomes.