Bitcoin's BIP-110 soft fork is set to begin mandatory signaling next week, with activation expected in early September. The upgrade introduces new transaction restrictions that will be enforced for roughly a year. Miners must signal support at block height 961,632, projected for August 9, or risk a chain split.
The signaling timeline
BIP-110 uses a 55% signaling threshold. Mandatory signaling starts at block 961,632, around August 9. If enough miners signal, the fork locks in by block 963,648, expected in late August. Activation follows at block 965,664, likely in early September. The restrictions then apply for 52,416 blocks — about one year.
What the restrictions cover
The soft fork bans several transaction types: large data pushes, oversized output scripts, undefined witness versions, Taproot annexes, deep Taproot control blocks, OP_SUCCESS opcodes, and certain Tapscript conditionals. UTXOs created before activation are grandfathered, so standard monetary uses remain compatible. Most corporations using Bitcoin as a store of value or via third-party payment providers need no action. Those running their own full node must decide whether to adopt BIP-110.
Chain split risks
A BIP-110 node rejects blocks that fail to signal bit 4 during mandatory signaling and blocks with non-compliant transactions after activation. A non-BIP-110 node accepts both compliant and non-compliant blocks, following the chain with the most accumulated proof of work. If miners build a non-compliant chain, BIP-110 nodes may separate from the broader network. Miners face high economic exposure during a split and must choose which branch to mine, weighing chainwork, signaling, and market value.
Exchanges and custodians should prepare for settlement uncertainty. The standard six-confirmation rule loses value during a split. Operators must raise confirmation requirements, monitor both branches, and delay final settlement until one branch decisively accumulates more work. Chain splits can lead to false confirmations and double-spend risk.
The next concrete date is block 961,632, projected for August 9. That's when the clock starts ticking for miners and node operators to pick a side.
