README

JSON schemas for upgrading items found in older Minecraft: Bedrock world saves

Background

As with blocks, Bedrock doesn't auto upgrade items (e.g. in inventories, item frames, dropped items, etc) unless the chunk they were in has been loaded and saved.

This means that any program that wants to support all Minecraft: Bedrock worlds needs to know how to upgrade this old data.

Repository contents

• id_meta_upgrade_schema subdirectory contains a list of JSON schemas for upgrading from version to version incrementally.
• item_legacy_id_map.json contains a mapping of legacy numeric IDs to their string ID counterparts (up to 1.16, although numeric IDs haven't been used in vanilla world saves since 1.5)
• 1.12.0_item_id_to_block_id_map.json contains a mapping of item IDs to corresponding block IDs for all blockitems.

Recommended methods for deserializing old data

Items are rather more of a pain to handle than blocks due to the lack of any versioning. This means we can only guess at the actual version and/or apply all upgraders all the time.

Classic items (MCPE <= 1.5, PM <= 1.12)

1. start with int ID + meta
2. 1.16 string ID via item_id_map.json -> string ID + meta
3. deserialize as medieval item

Medieval items (MCPE 1.6 - 1.8)

1. start with string ID + meta
2. if ID found in 1.12.0_item_id_to_block_id_map.json, deserialize as blockitem; otherwise as normal item

Non-blockitems

1. deserialize as modern item

Blockitems

1. string block ID via 1.12.0_item_id_to_block_id_map.json -> string block ID + meta
2. convert to blockstate using BedrockBlockUpgradeSchema data -> blockstate NBT
3. deserialize blockstate NBT as block

Modern items (MCPE 1.9 - present)

1. start with string ID + meta / blockstate NBT
2. if blockstate NBT found, deserialize as blockitem; otherwise as normal item

Non-blockitems

1. current string ID via schemas provided in id_meta_upgrade_schema/ subdirectory -> current string ID + meta

Blockitems

1. deserialize blockstate NBT as block (may require BedrockBlockUpgradeSchema for upgrading)