The psbtbumpfee RPC is used to increase the fee of an opt-in RBF (Replace-By-Fee) transaction by creating a new transaction with a higher fee.

How is this used?

The psbtbumpfee RPC is primarily used to increase the fee of an opt-in RBF transaction in situations where the original fee is insufficient to confirm the transaction promptly. This can be necessary to accelerate transaction confirmation during periods of network congestion or when the initial fee was set too low. By bumping the fee, users can prioritize their transactions for inclusion in the blockchain. This RPC command is particularly useful for wallets that support RBF transactions and need to adjust transaction fees dynamically after the transaction has been broadcasted. It allows users to replace the original transaction with a new one that includes a higher fee, ensuring faster confirmation without waiting for the original transaction to be confirmed or dropped from the mempool.