Let's say I broadcast a transation tx0 signaling RBF replaceability. Later on, I realize it has a small amount of fees, so I send another transaction tx1 that spends the same inputs than tx0, but this time with higher fees.
Which is the default bitcoind/bitcoin-qt behaviour regarding the relaying of tx1? Would all nodes broadcast the new version of the transaction or does the relay policy depend on the
mempoolreplacement parameter? Do any special rules apply to the relaying of the replacement transaction?
I have seen that Peter Todd's RBF proposal included a NODE_REPLACE_BY_FEE service bit. Is anything like this included in the current version?