1.21.5 Pre-Release 1 — release journal
What 1.21.5-pre1 changed for data packs, measured against 25w10a, the build before it. Released 2025-03-11; development build — not a release.
💡 No measured change
Same data pack format, same registries. That is the strongest safe-for-data-packs signal a diff can give, and it is still not proof — behaviour changes and bug fixes are invisible to it.
Formats
| 25w10a | 1.21.5-pre1 | |
|---|---|---|
| Data pack format | 70.0 | 70.0 |
| Resource pack format | 54.0 | 55.0 moved |
| Data version | 4319 | 4320 |
Registries
No registry gained, lost or changed an entry.
The official notes
Read the 1.21.5 Pre-Release 1 article on minecraft.net.
That article's technical changes are grouped under these headings — open it for the detail:
- Network Protocol
- Resource Pack Version 55
Minecraft Wiki page for 1.21.5-pre1.
In the journal
← 25w10a · All builds · 1.21.5-pre2 →
Sources
- misode/mcmeta — 1.21.5-pre1 summary — formats and registries, generated from the game’s own data.
- minecraft.net — 1.21.5 Pre-Release 1 — section names only.