Segwit | Replace-by-Fee

Segwit Addresses

What are segwit addresses? Transactions that spend bitcoins secured by segregated witness (segwit) use less block weight than equivalent non-segwit (legacy) transactions, allowing segwit transactions to pay less total fee to achieve the same feerate as legacy transactions.

Tested: version 3.16.0.13 on Android

Tested on: 2022-10-12

Receive support

  • Allows receiving to P2SH-wrapped segwit
    Allows the generation of P2SH-wrapped (either P2WPKH or P2WSH) segwit receiving addresses.
  • Allows receiving to bech32 segwit addresses
    Allows the generation of bech32 native (either P2WPKH or P2WSH) segwit receiving addresses.
  • Default receiving address is P2SH-wrapped P2WPKH
    This service generates P2SH-wrapped P2WPKH segwit receiving addresses by default.

Send support

  • Allows sending to bech32 P2WPKH addresses
    Allows sending to bech32 P2WPKH native segwit addresses.
  • Allows sending to bech32 P2WSH addresses
    Allows sending to bech32 P2WSH native segwit addresses.
  • Creates bech32 change addresses
    When sending, generates bech32 (either P2WPKH or P2WSH) segwit change addresses.

Usability

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Mycelium generates P2PKH, P2SH-P2WPKH, and P2WPKH receive addresses.
Mycelium generates P2PKH, P2SH-P2WPKH, and P2WPKH receive addresses.

Mycelium can send to any bech32 addresses.
Mycelium can send to any bech32 addresses.


Replace-by-Fee (RBF)

What is Replace-by-Fee (RBF)? An unconfirmed transaction can be replaced by another version of the same transaction that spends the same inputs. Most full nodes support this if the earlier transaction enables BIP125 signaling and the replacement transaction increases the amount of fee paid. In terms of block chain space used, this is the most efficient form of fee bumping.

Tested: version 3.16.0.13 on Android

Tested on: 2022-10-12

Receiving support

  • No notification
    There are no incoming transaction notifications for this service.
  • Received transaction labeled replaceable in list
    Visually indicates that an incoming transaction has signaled RBF.
  • Received transaction not labeled replaceable in transaction details
    Does not visually indicate that a received transaction has signaled RBF when viewing the transaction details.
  • Shows replacement transaction only
    Only the replacement transaction is shown in the transaction list. No original transaction is shown.

Sending support

  • Does not signal BIP125 replacability when sending transactions
    Does not allow sending of BIP125 opt-in-RBF transactions in the interface.
  • Not tested: Does transaction list show whether sent transactions signal RBF?
    We were not able to test this because sending a BIP125 signaling transaction is not supported.
  • Not tested: Does transaction details page show whether received transaction signals RBF?
    We were not able to test this because sending a BIP125 signaling transaction is not supported.
  • Not tested: Are replacement and original sent transactions displayed?
    We were not able to test this because sending a BIP125 signaling transaction is not supported.

Usability

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Sending Transaction - Default send transaction screen. No options for RBF while sending or in app settings. Miner fee slider.
Sending Transaction - Default send transaction screen. No options for RBF while sending or in app settings. Miner fee slider.

Receiving Transaction Signaling RBF - Fee Bump is displayed as double spend. Sometimes, when receiving any transaction, no unconfirmed transactions show.
Receiving Transaction Signaling RBF - Fee Bump is displayed as double spend. Sometimes, when receiving any transaction, no unconfirmed transactions show.


Attempting Transaction Replacement - Transaction list. No option to bump since transaction sent without RBF. Unconfirmed transaction without RBF signal is shown without warning.
Attempting Transaction Replacement - Transaction list. No option to bump since transaction sent without RBF. Unconfirmed transaction without RBF signal is shown without warning.