A Bitcoin Core addition called Opt-In Replace-By-Fee (Opt-in RBF) allows transactions to be flagged as replaceable and replaced until the transaction gets confirmed in the next block, according to Nasdaq. It gives wallets the chance to add a signal to a transaction that gives permission for nodes to update the transaction.
Opt-in RBF was part of the original bitcoin software but was removed due to denial of service problems. Opt-In RBF solves this problem by adding a higher fee for transaction replacement.
An Option For Wallets
Opt-in RBF consists of a change to the network relay code and memory pool that gives wallets the option to add a signal to transactions giving permission for full nodes to update the specific transaction. The feature marks a variation of RBF, also included in Bitcoin Core. Bitcoin journalist Aaron Van Wirdum provided a summary of the cases for and against RBF in Bitcoin Magazine.
Bitcoin Core developer Peter Todd blogged that opt-in RBF wallets are not currently ready to deploy