Minecraft wiki entry for History, associated text: When the LevelDB format was initially introduced in Pocket Edition v0.9.0 alpha, the terrain of each chunk was stored under one key (the "LegacyTerrain" record). This was replaced in Pocket Edition 1.0.0 by the "SubChunkPrefix" record, storing each 16×16×16 subchunk separately as a different leveldb key, analogous to an Anvil "section".[1] A new version of the subchunk format enclosing "Block Storage" records was introduced in Bedrock Edition 1.2.13.[2]