Bitcoin Core 30
The 2025 Core release that relaxed its data filter — and lit the spam war.
In plain words
Bitcoin Core version 30, October 2025, changed one default. Before: a node refused to relay transactions carrying more than 83 bytes of extra data. After: up to 100,000. The maintainers' case: the data got mined anyway, so the filter only hid the truth. The critics' case: a green light for spam. The rules of the money did not move — only what a stock node volunteers to pass along.
Why it matters
- One default setting became Bitcoin's loudest fight since the block size war.
- It fueled Bitcoin Knots as the filter-keeping alternative — and set the stage for BIP 110.
- What a node relays is its choice. What a block may contain is everyone's.
Numbers that matter
- 83 → 100,000 bytes — the old vs new default cap on relayed extra data.
- October 10, 2025 — release date.
Not to be confused with
- A rule change — every block valid before is valid after; only relay manners moved.
Go deeper
- Core 30.0 release notes — the change in the project's words.
- Bitcoin Knots
- BIP 110
Updated 2026-07-29