BIP-110 Could Split Bitcoin In New Soft Fork Fight, Jameson Lopp Warns

Jameson Lopp is escalating his criticism of BIP-110, arguing the proposal could trigger a disruptive Bitcoin chain split while failing to stop the behavior it is meant to curb. In a Feb. 23 post, Lopp frames the plan as a consensus-layer response to a policy and cultural dispute around transaction “spam,” with risks that extend well beyond mempool debates.

BIP-110 is pitched as a soft fork led by Luke Dashjr that would temporarily restrict arbitrary data in transactions. Lopp summarizes it as adding seven new transaction-validity restrictions, including limits on where data can be placed and constraints on certain script behavior, but says the tradeoffs are far more severe than supporters admit. He calls the proposal “reckless and doomed to fail,” setting the tone for a post that is less a technical explainer than a warning about governance and coordination risk.

Why Lopp Thinks The Activation Path Is Dangerous For Bitcoin

The core of Lopp’s argument is not just what BIP-110 changes, but how it tries to activate. He points to the proposal’s 55% miner-signaling threshold for a user-activated soft fork and says that low bar materially increases the probability of two competing chains if the ecosystem is not aligned.

He also stresses that BIP-110 nodes would reject non-compliant blocks outright, which raises coordination risk compared with soft forks that old nodes can continue to follow without enforcement conflicts.

Lopp is especially pointed on the mandatory activation posture at block height 961,632. In one of the sharpest passages, he writes: “This is not a neutral, low-drama deployment posture. It’s dogmatic bullying. […] you cannot pretend it’s low-risk.” He ties that warning to a broader point: even if one views UASF tactics as legitimate, the proposal’s design increases the odds of a messy failure mode if miners, exchanges, wallets, and infrastructure providers do not converge in time.

He also pushes back on comparisons to 2017, noting that the UASF many people cite in the SegWit era never actually had to run to the edge because SegWit activated via miner signaling instead. That distinction matters in Lopp’s framing, because BIP-110 proponents are, in his view, leaning on a historical precedent that did not test the exact scenario they now describe as manageable.

Another major section of Lopp’s post targets the claim that BIP-110 has meaningful grassroots momentum. He argues that raw node counts (roughly 20% run Knots) are a weak proxy for consensus because signaling is cheap, node operation can be low-cost, and Tor addresses are “effectively zero” cost to create at scale. He publishes a breakdown of reachable nodes and highlights the higher Tor-to-IPv4 ratio among Knots and BIP-110 signaling nodes as a reason to treat node-count narratives cautiously.

On mining support, Lopp says the gap is more straightforward. At the time of publication, he writes miner signaling was “precisely […] zero,” and he cites public opposition from F2Pool while arguing miners have limited incentive to back a proposal that could reduce fee revenue. That point reinforces his broader thesis that BIP-110 supporters are overestimating social signaling and underestimating the role of economically significant actors in Bitcoin upgrade politics.

Lopp’s post ultimately reads as a warning that the immediate issue is not simply whether BIP-110 activates, but what the campaign reveals about where Bitcoin’s internal dispute over neutrality, censorship resistance, and block-space usage is heading. Even a failed fork push, in his framing, can still impose real costs by forcing operators and businesses to plan around low-probability but high-impact coordination failure.

At press time, Bitcoin traded at $62,791.