BIP-110 post-mortem: why a soft fork backed by 2.5% of miners stalled after two blocks

On 8 August 2026, at block 961,632, nodes running the BIP-110 rule change stopped following the main Bitcoin chain. Only about 2.5% of mining power supported them. Their new chain produced two blocks and stopped. On 23 October a panel in Lugano will look back at what went wrong.

BIP-110 was a proposed soft fork: a tightening of Bitcoin's rules. Its supporters, mostly from the Bitcoin Knots community, wanted to limit what they call "spam", meaning large amounts of non-payment data stored in transactions.

A soft fork usually activates when most miners signal that they are ready. BIP-110 had a backup plan: after a set block height, nodes running it would reject any block that did not signal support. Supporters hoped this would push miners to join.

• In the 2,016 blocks before the deadline, only 51 blocks signalled support. That is about 2.53%, against a 55% threshold.
• At block 961,632 the mining pool Antpool produced a block without the signal. The main network accepted it.
• Nodes running BIP-110 rejected that block. They followed a different block 961,632, mined by a small group called Roughnecks through the Ocean pool. From that moment there were two chains.
• Roughnecks mined one more block, 961,633, and then the BIP-110 chain went quiet.

Bitcoin adjusts mining difficulty every 2,016 blocks. The BIP-110 chain kept the same difficulty as Bitcoin but had only a tiny share of the mining power, so its blocks came very slowly. Its coin had no market, so miners had no reason to help.

• By 11 August the fork was 326 blocks behind. A live monitor cited by CoinDesk estimated its next difficulty adjustment was 6.3 years away.
• On 12 August BIP editor Murch counted 4 blocks on the BIP-110 branch against 533 on the main chain.

The editors of the Bitcoin Improvement Proposals repository moved BIP 110 to the "Closed" status. The change was merged on 10 August 2026. On 12 August Murch added that "the BIP110 deployment attempt was decisively rejected by the Bitcoin network."

• If you use a normal wallet, an exchange, or a node that does not enforce BIP-110, nothing changed for you.
• If you ran a node with BIP-110 enforcement, it followed the minority chain. Transactions you saw there were not on the main Bitcoin chain.
• The lesson: a rule change needs miners and the wider economy on board. Forcing it with a small minority creates a separate chain, not a new Bitcoin rule.

23 October, 14:30 Lugano / 15:30 MSK, WAGMI Stage: "The next soft fork – BIP 110 Post Mortem" with Jimmy Song, Samson Mow, Knut Svanholm and Chris Seedor, moderated by Nico Moran.

Related: the debate "Funding Bitcoin: Independence, Incentives, and Influence" (23 Oct, 16:00 / 17:00 MSK) on who pays Bitcoin Core developers. Watch live network data on our Network page.