Bitcoin Core developers are proposing to remove legacy opt-in replace-by-fee (RBF) signaling from wallet software after full RBF became standard network policy. According to reports from CoinDesk, Bitcoin Core contributor rkrux proposed stripping out the opt-in Replace-by-Fee signaling mechanism on June 16, 2026, arguing that the feature became redundant when Bitcoin Core version 28.0 made full RBF the default mempool policy back in October 2024. The opt-in version was formalized in BIP 125 between 2015 and 2016, and first shipped in Bitcoin Core 0.12, working by tweaking a specific field in the transaction called nSequence. When Bitcoin Core 28.0 launched with full RBF enabled by default, the entire opt-in dance became pointless, as any unconfirmed transaction can now be replaced with a higher-fee version regardless of explicit flagging.
The legacy RBF signal creates unnecessary on-chain fingerprints that can reveal which wallet software was used, as reported by CoinDesk. Community participant Murch, a well-known Bitcoin Core contributor, explained that stopping to signal replaceability makes it sound like it's a matter of dropping a fingerprint, but every sender has to pick a sequence for every input. According to data from mainnet-observer, roughly 75% of transactions now use the MAX-2 signaling value, meaning most wallets have already converged on a de facto standard. However, the remaining 25% of wallets use distinctive nSequence values, which become fingerprints that chain analysis firms can use to identify which wallet software created a transaction, which can then be correlated with other metadata to narrow down the sender's identity.
Developers are coordinating on a common default input sequence number to make transactions from different wallets look similar and harder to track. As reported by CoinDesk, rkrux suggested that the default input sequence number should be the one that's agreed on by the wider wallet community as best practice. This standardization approach aims to prevent transactions from different wallets from appearing distinct on-chain, which makes them easier to track. Community feedback from prominent developers reinforced this concern, with Murch and SomberNight from the Electrum wallet project both weighing in on the discussion, with the data suggesting that standardization across wallets would meaningfully reduce fingerprinting exposure.
Implementing this removal requires careful planning because if different wallets delete this replace function in different ways, transactions will look distinct on-chain, making them easy to track. According to CoinDesk, removing a signal may sound simple, but in Bitcoin, where the signal is a mandatory field that must be filled with a value, the process is more complex than just deleting a button or sticker. The proposal targets wallet-level behavior, specifically how Bitcoin Core's built-in wallet constructs transactions before broadcasting them. Other wallet implementations would need to adopt similar changes independently, though the 75% convergence on MAX-2 suggests the ecosystem is already moving in this direction organically.
