Bitcoin developer Matt Corallo has estimated an 80% chance that BIP-54, a proposed upgrade designed to fix four longstanding vulnerabilities in the network, will become Bitcoin’s next soft fork.
Summary
- Bitcoin developer Matt Corallo has estimated an 80% chance that BIP-54, a proposal to fix four longstanding network vulnerabilities, will become Bitcoin’s next soft fork.
- The proposed upgrade would address weaknesses in mining difficulty adjustments, block validation, Merkle tree proofs and duplicate coinbase transactions.
- BIP-54 has no confirmed activation date, although developer estimates gathered at TABconf suggest the upgrade could arrive in 2027 or more likely 2028 and beyond.
- Some developers have questioned whether Bitcoin should prioritize maintenance over new features, while Corallo believes the upgrade could help establish a clearer process for future soft forks.
According to a November 4 Decrypt report, Corallo discussed the proposal during an appearance on MARA Foundation TV with MARA Foundation head Isabel Foxen Duke, where he explained why developers could prioritize fixing existing consensus problems before introducing new features.
The proposal, known as the Great Consensus Cleanup, dates back to work Corallo introduced in 2019 and has since developed into a formal Bitcoin Improvement Proposal co-authored with developer Antoine Poinsot.
Although the upgrade has no confirmed activation date, Corallo believes it addresses technical problems that developers generally recognize without requiring major changes to Bitcoin’s functionality.
“There’s a laundry list of things we know of that we really need to clean up,” Corallo said, describing the vulnerabilities as genuine concerns but not immediate threats to the network.
BIP-54 proposes fixes for four Bitcoin vulnerabilities
The official BIP-54 specification outlines changes to Bitcoin’s difficulty adjustment rules, transaction validation process, Merkle tree structure and coinbase transaction requirements.
One of the problems involves a vulnerability known as the timewarp attack, which could allow miners controlling a majority of Bitcoin’s computing power to manipulate block timestamps.
Bitcoin normally adjusts mining difficulty every 2,016 blocks, or approximately two weeks. By exploiting the existing timestamp rules, an attacker could artificially lower difficulty and cause new blocks to be produced faster than intended.
The proposal’s technical documentation estimates that an attacker could potentially push mining difficulty to its minimum within 38 days under extreme circumstances.
To address the problem, BIP-54 introduces restrictions on timestamps at the beginning and end of each difficulty adjustment period, including a two-hour allowance intended to accommodate normal variations.
Another proposed change targets specially constructed blocks that require unusually large amounts of computing power to validate.
According to the specification, some blocks could take several minutes to process on powerful computers and potentially hours on less capable machines, allowing malicious miners to slow competitors.
BIP-54 would limit certain signature verification operations to 2,500 per transaction. Its authors estimate that the restriction could reduce worst-case block validation time by a factor of 40.
The third fix concerns Merkle tree vulnerabilities involving transactions with exactly 64 bytes of non-witness data.
Under certain conditions, such transactions can resemble internal Merkle tree nodes, potentially allowing attackers to deceive lightweight Bitcoin clients into accepting fraudulent transaction inclusion proofs.
The proposed rules would invalidate transactions of that specific size, eliminating the underlying ambiguity.
The final change addresses duplicate coinbase transactions, which are special transactions miners create to collect block rewards.
BIP-54 would introduce new requirements for coinbase transaction fields to prevent historical transaction identification problems from resurfacing at future block heights.
The specification identifies block 1,983,702 as the earliest future height where a duplicate coinbase transaction could occur under the existing rules.
Bitcoin developers face disagreements over future upgrades
Despite Corallo’s confidence, the proposal has attracted criticism from developers who believe Bitcoin should prioritize upgrades that introduce new capabilities.
Paul Sztorc, co-founder and CEO of LayerTwo Labs, described the prospect of activating BIP-54 as “kind of depressing” in a post on X, arguing that the proposal amounts to maintenance without adding functionality.
Sztorc said developers he surveyed at TABconf in Atlanta generally expected the cleanup proposal to become Bitcoin’s next soft fork.
Their estimates, however, suggested a lengthy wait, with the earliest prediction pointing to September 2027 and most expecting activation in 2028 or later.
The discussion follows years of disagreements over Bitcoin protocol changes since Taproot activated in November 2021.
In September, crypto.news reported Sztorc’s concerns that Bitcoin could struggle to activate further soft forks because of disagreements over how consensus changes should be approved.
He specifically pointed to OP_CAT, a proposed upgrade that would restore an operation allowing Bitcoin scripts to combine data and support more complex spending conditions.
Other proposals, including OP_CHECKTEMPLATEVERIFY under BIP-119, have faced similar difficulties securing sufficient support across the Bitcoin ecosystem.
Meanwhile, quantum computing has become another subject of protocol discussions. Coinbase recently outlined possible approaches to protecting Bitcoin against future quantum threats, including BIP-360 and its proposed Pay-to-Merkle-Root output structure.
Unlike those proposals, BIP-54 focuses on correcting weaknesses in Bitcoin’s existing consensus rules.
Corallo wants BIP-54 to establish a soft fork activation process
Beyond the technical changes, Corallo believes the upgrade could help developers establish a more predictable process for introducing future Bitcoin soft forks.
He explained that Bitcoin upgrades have historically involved difficult technical decisions, but disagreements over activation methods have become an equally important obstacle.
During the Taproot deployment debate, participants disagreed over whether miners should signal support before activation or whether users should enforce an activation deadline.
Corallo suggested that developers could use the BIP-54 deployment process to work through similar disagreements and establish procedures that could be reused for subsequent upgrades.
The proposal reached complete specification status on May 22, 2026, according to its official changelog, although that designation does not constitute network activation.
Its compatibility provisions state that the changes would tighten existing validation rules while remaining compatible with nodes that have not upgraded.
The authors nevertheless encourage node operators to update their software so they can independently enforce the proposed restrictions.
For miners, the documentation notes that Bitcoin Core versions 29.0 and 30.0 already include block template protections compatible with certain proposed restrictions, while mining pools would need to ensure their coinbase transactions meet the new requirements.
