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.
Old worlds consist of a finite map with an area of 256x256 blocks, barricaded with invisible bedrock. They can generate with any of the current biomes (excluding roofed forest); however, as a result of their limited size, only several biomes can be generated per world.
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
|Pocket Edition Alpha|
|0.1.0||Released along with the first official version of Pocket Edition. At the time, this was the only available world type.|
|Featured a basic terrain generation with 3 "biomes" (Forest, Taiga, and Desert).|
|0.1.3||Cacti now generate in deserts|
|0.9.0||Old is now an optional world type, with the addition of Infinite and Flat world types.|
|Changed terrain generation, adding new generated structures, biomes, and foliage colors.|
|0.11.0||Old worlds can now be converted into Infinite worlds.|
Issues relating to “Old” are maintained on the issue tracker. Report issues there.