In a recent update to Bitcoin Core, the `mempoolfullrbf` option has been removed, alongside deprecating the `fullrbf` and `bip125-replaceable` flags. Here's a breakdown of the key changes:
1. Goodbye to `mempoolfullrbf`
- The `-#mempoolfullrbf ` option, which previously allowed users to force full Replace-by-Fee (RBF) for transactions, has been removed.
- The feature was found to have limited adoption by the network, making it unnecessary to keep in the codebase.
2. Deprecation of `fullrbf` and `bip125-replaceable`
- The flags indicating whether a transaction was replaceable under RBF (specifically `fullrbf` and `bip125-replaceable`) are now deprecated.
- These flags were not widely respected by the network, leading to their removal in favor of simplifying transaction signaling.
3. No Need to Signal BIP125 Replaceability
- The requirement for transactions to signal BIP125 replaceability is now obsolete.
- With the network not consistently enforcing full RBF, this behavior no longer needs to be explicitly signaled in transactions.
4. Wallet Adjustments Coming in a Separate PR
- While this change removes the full RBF option for users, wallet-related updates to address concerns like fingerprinting and adapting to the evolving network will be handled in a separate pull request.
Why Was This Change Made?
The decision to remove these features stems from the lack of widespread adoption of full #RBF and #BIP125 signaling by the network. By removing these now-obsolete features, the codebase becomes cleaner and easier to maintain.

This update brings #BitcoinCore in line with current network dynamics, removing features that have limited real-world impact and simplifying the software for developers and users alike.
$BTC