Bitcoin's BIP-110 soft fork attempt begins mandatory signaling phase

The Bitcoin blockchain split into two branches on August 8, 2026, at block 961,632 as nodes enforcing the controversial BIP-110 soft fork began rejecting non-signaling blocks. Written by pseudonymous developer Dathon Ohm, BIP-110 seeks to temporarily restrict non-financial data like Ordinals. Despite having only 2.53% miner support, proponents initiated a user-activated soft fork. The minority chain quickly fell behind the main chain, while developers warned holders of replay attack risks if they move coins.

BIP-110 blockchain split

• ▪BIP-110 nodes followed an alternative block at height 961,632 produced through the Ocean mining pool by a miner named Roughnecks
• ▪The Bitcoin blockchain split into two branches on Saturday, August 8, 2026, at block 961,632 when nodes running BIP-110 began rejecting blocks that did not signal support for the proposal
• ▪AntPool mined the first block at height 961,632 without the BIP-110 signal, which was accepted by the main network but rejected by BIP-110 nodes
• ▪The minority BIP-110 branch fell behind the dominant main chain quickly after the split, reaching only block 961,633 while the main chain had reached block 961,640 as of Saturday evening

User-activated soft fork mechanism

• ▪Public miner signaling for BIP-110 reached only 2.53% (51 of 2,016 blocks) prior to the split, far below the 55% threshold required for ordinary activation
• ▪BIP-110's deployment schedule sets blocks 961,632 through 963,647 as a mandatory-signaling window, with transaction restrictions scheduled to take effect at block 965,664
• ▪BIP-110 is designed as a user-activated soft fork (UASF) that relies on node operators to enforce new rules from a predetermined block height regardless of miner support
• ▪Bitcoin developer Chris Guida rebased preliminary code on August 1, 2026, for a proof-of-work change as a contingency if miners opposed BIP-110

Replay attack risk

• ▪Developer Kevin Loaec warned that the safest course for non-experts is to avoid moving or selling coins during the split because BIP-110 lacks built-in replay protection until at least early September
• ▪Selling duplicate coins from the BIP-110 fork poses a replay attack risk where transactions could be copied and executed on the main chain, draining the seller's real bitcoin

BIP-110 technical restrictions

• ▪BIP-110 was written by pseudonymous developer Dathon Ohm to temporarily restrict how much non-payment data, such as Ordinals and Runes, can be stored on the Bitcoin blockchain
• ▪The proposed BIP-110 rules would restrict certain data pushes and witness elements to 256 bytes and temporarily limit several Taproot features to discourage inscriptions
• ▪BIP-110 proposes temporary consensus restrictions lasting about one year that would limit most new output scripts to 34 bytes and cap OP_RETURN outputs at 83 bytes

Bitcoin governance debate

• ▪Prominent Bitcoin figures Michael Saylor and Adam Back voiced their opposition to BIP-110, arguing that the network's fee market should determine block space use
• ▪BIP-110's author Dathon Ohm advised miners to upgrade to Bitcoin Knots to enforce the rules, warning that running Bitcoin Core would become insecure
• ▪BIP-110 supporters, including Ocean CTO Luke Dashjr, argue that permanent non-financial data storage burdens node operators and competes with monetary transactions