Item id remap tables for 1.8 through 1.12 map wrong values
Author: matheustavarestrindadeCreated Sep 18, 2026Updated Sep 18, 2026
Labelsbugprotocolitemdata
What happens
Every item id remap table for 1.8 through 1.12 maps wrong values, so clients on those versions receive the wrong item for almost everything. This is how a book and quill ends up unopenable on 1.12: the client never sees a writable book.
Evidence
Comparing the generated tables against the official item registries:
| item | table says | real id |
|---|---|---|
| stone | 16 | 1 (all versions) |
| paper | 5424 | 339 (1.12) |
| writable_book | 6176 | 386 (1.12) |
Checked: 1.8, 1.9, 1.10, 1.11 and 1.12 are wrong, while 1.13.2, 1.14, 1.16.2, 26.2 and 26.3 are correct.
Where
crates/pumpkin-data/src/generated/item_id_remap.rs, the ITEM_ID_REMAP_V_26_3_TO_V_1_7_6, _V_1_8, _V_1_9, _V_1_10, _V_1_11 and _V_1_12 tables. The values look like they were built from a different registry than the target version.
Source: Pumpkin-MC/Pumpkin