Bitcoin Core contributor rkrux has proposed stripping out the opt-in Replace-by-Fee signaling mechanism from Bitcoin wallets, arguing that the feature became redundant when Bitcoin Core version 28.0 made full RBF the default mempool policy back in October 2024.
What RBF signaling actually does, and why it no longer matters
Replace-by-Fee is the mechanism that lets you bump a Bitcoin transaction’s fee after you’ve already broadcast it. The opt-in version was formalized in BIP 125 between 2015 and 2016, and first shipped in Bitcoin Core 0.12. It worked by tweaking a specific field in the transaction called nSequence. If your wallet set this field to signal “I’m replaceable,” nodes would allow a higher-fee version to take its place in the mempool, the waiting room for unconfirmed transactions.
When Bitcoin Core 28.0 launched in October 2024 with full RBF enabled by default, the entire opt-in dance became pointless. Full RBF means any unconfirmed transaction can be replaced with a higher-fee version, regardless of whether the sender explicitly flagged it.
So the proposal, floated around June 16, 2026, is essentially asking: why are wallets still putting on the wristband?
