Bitcoin News Today: Developer rkrux open sourced Bitcoin Core PR #35405 and posted to the Bitcoin-Dev mailing list on June 19, 2026, proposing to remove the old opt-in Replace by Fee (RBF) signal from wallet transactions, arguing that the BIP125 indicator has become a redundant identifier on-chain now that full RBF is the network’s default memory pool policy.
This isn’t just code cleanup. This is a coordinated Bitcoin privacy initiative that requires alignment across wallets to a single default nSequence value, a structurally more complex issue than removing a flag.
rkrux posted to the Bitcoin-Dev mailing list proposing that wallets stop reporting the RBF opt-in in transactions they create…
– Bitcoin Optech (@bitcoinoptech) June 19, 2026
Bitcoin News Today: RBF Signal Removal: Why the Old Flag Now Creates More Risk Than It Solves
According to BIP125, a transaction was considered overwritten if an entry had a lower nSequence value 0xffffffff − 1, a mechanism introduced in Bitcoin Core 0.12.0 in February 2016 to allow voluntary increase in fees for unconfirmed transactions without disrupting memory pool behavior first observed on the network.
Bitcoin Core’s subsequent move to full RBF as the default policy, began with the mempoolfullrbf The option added in version 24.0 and later made the default unconditional, making this signal operationally inert. As rkrux stated in the mailing list post: “The main reason for its removal is that since full RBF became standard policy, this signaling has become redundant.” Nodes running the current default policy will overwrite any transaction regardless of its nSequence values, according to Bitcoin Optech’s RBF topic documentation.
A decade-old Bitcoin transaction indicator became dead code 20 months ago. Bitcoin Core contributor rkrux wishes wallets would stop defining it. The reason is confidentiality.
Replace with Fee allows you to increase the fee of a blocked Bitcoin transaction after you have already released it. Membership of BIP 125… pic.twitter.com/CvIlt3vQqa
— Taurus (@Taurus4BTC) June 22, 2026
The residual cost of maintaining the signal is wallet fingerprinting. Since the nSequence field is mandatory, wallets cannot leave it blank, any wallet that removes the BIP125 flag without coordinating on a replacement value will produce transactions with a distinct sequence pattern, making them identifiable on-chain. The concern is directly analogous to on-chain tracking patterns that appear in the analysis of long-term holder behavior, where wallet-level metadata leaks inform cycle positioning well beyond what participants intend to disclose.
Sequence Number Coordination: Arguments for MAX-2 as the Default System
Community participant Murch, identified in Optech’s coverage as Gloria Zhao, described the fundamental tension: “stopping to signal replaceability feels like dropping a fingerprint, but…each sender has to choose a sequence for each entry.” » The field must have a value; the question is to know on which value all the portfolios converge.
Murch and Electrum developer SomberNight have both favored MAX-2 as the standard default, a position reinforced by Optech data showing that MAX-2 is already the dominant nSequence value in approximately 75% of Bitcoin transactions.
Moving to MAX-1 – a value without signaling, was considered but shelved because it would make Bitcoin Core transactions visually distinct from the existing majority, creating a new fingerprint rather than eliminating one. The goal, as rkrux puts it, is for the broader wallet community to agree on “one that has been accepted by the broader wallet community as best practice.”
🔴Bitcoin developers move to remove RBF signaling, citing privacy leak and redundancy
Bitcoin developers are coordinating to remove replacement by fee (RBF) signaling from wallet software. The explicit membership flag became redundant after the network adopted full-RBF as a standard… pic.twitter.com/SRsQQMhk3v
– NewsTongue (@NewsTongueX) June 22, 2026
There is also a backwards compatibility rationale. A proposed future upgrade associating nVersion=3 transactions with RBF package semantics would reserve MAX and MAX-1 for separate policy behavior, making MAX-2 the safest long-term default and reducing migration friction as these changes are deployed.
Industry Implication: Zero-Conf Merchant Workflows and Multi-Portfolio Reach
The change preserves the full fee increase capability for users, the ability to replace an unconfirmed transaction with a higher fee version is not affected. What changes is the visibility of this option in the transaction structure itself. Trader workflows that previously used the BIP125 visible membership indicator as a proxy risk signal for accepting transactions without confirmation will need to treat all unconfirmed transactions as potentially policy replaceable, which is the exact technical posture since full RBF became the default.
We believe the most consequential result is the precedent for coordination between portfolios. If Bitcoin Core merges the PR and downstream wallets and then normalizes to MAX-2, the episode will represent one of the most orderly ecosystem-wide default alignments in Bitcoin’s recent development, a contrast to the fragmented deployment of full-RBF itself, which took place on a wallet-by-wallet basis for several years before reaching network-level consistency.
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Daniel Frances is a technical writer and Web3 educator specializing in macroeconomics and DeFi mechanics. Hailing from crypto since 2017, Daniel leverages his experience in on-chain analytics to write evidence-based reports and in-depth guides. He holds certifications from the Blockchain Council and is dedicated to providing “insight gain” that overcomes market hype to find real utility for blockchain.
