1.21.9 Pre-Release 2 — release journal
What 1.21.9-pre2 changed for data packs, measured against 1.21.9-pre1, the build before it. Released 2025-09-19; development build — not a release.
⚠ Format moved, no registry changed
The data pack format moved but no registry entry changed. That is not a no-op: the change is in file schemas — field shapes and required keys — which a registry diff cannot see. Read the article's technical sections below.
Formats
| 1.21.9-pre1 | 1.21.9-pre2 | |
|---|---|---|
| Data pack format | 87.1 | 88.0 moved |
| Resource pack format | 69.0 | 69.0 |
| Data version | 4549 | 4550 |
Registries
No registry gained, lost or changed an entry.
The official notes
Read the 1.21.9 Pre-Release 2 article on minecraft.net.
The article has no technical-changes section — it lists bug fixes only, or predates that heading.
Minecraft Wiki page for 1.21.9-pre2.
In the journal
← 1.21.9-pre1 · All builds · 1.21.9-pre3 →
Sources
- misode/mcmeta — 1.21.9-pre2 summary — formats and registries, generated from the game’s own data.
- minecraft.net — 1.21.9 Pre-Release 2 — section names only.