Bitcoin Core version is now available from:

conwaytransport.com.au

or through BitTorrent:

magnet:?xt=urn:btih:1c72f17bca2cebefd05&dn=bitcoin-core&tr=udp%3A%2F%conwaytransport.com.au%3A80&tr=udp%3A%2F%conwaytransport.com.au%3A&tr=udp%3A%2F%conwaytransport.com.au%3A&tr=udp%3A%2F%conwaytransport.com.au%3A&tr=udp%3A%2F%conwaytransport.com.au%3A&tr=udp%3A%2F%conwaytransport.com.au%3A

This is a new major version release, including new features, various bugfixes and performance improvements, as well as updated translations.

Please report bugs using the issue tracker at GitHub:

conwaytransport.com.au

To receive security and update notifications, please subscribe to:

conwaytransport.com.au

If you are running an older version, shut it down. Wait until it has completely shut down (which might take a few minutes for older versions), then run the installer (on Windows) or just copy over (on Mac) or / (on Linux).

If your node has a txindex, the txindex db will be migrated the first time you run or newer, which may take up to a few hours. Your node will not be functional until this migration completes.

The first time you run version or newer, your chainstate database will be converted to a new format, which will take anywhere from a few minutes to half an hour, depending on the speed of your machine.

Note that the block database format also changed in version and there is no automatic upgrade code from before version to version Upgrading directly from x and earlier without redownloading the blockchain is not supported. However, as usual, old wallet versions are still supported.

Downgrading warning

The chainstate database for this release is not compatible with previous releases, so if you run and then decide to switch back to any older version, you will need to run the old release with the option to rebuild the chainstate data structures in the old format.

If your node has pruning enabled, this will entail re-downloading and processing the entire blockchain.

Bitcoin Core is extensively tested on multiple operating systems using the Linux kernel, macOS +, and Windows 7 and newer (Windows XP is not supported).

Bitcoin Core should also work on most other Unix-like systems but is not frequently tested on them.

From onwards macOS < is no longer supported. is built using Qt x, which doesn’t support versions of macOS older than

• Upgrading from or older currently results in memory blow-up during the roll-back of blocks to the SegWit activation point. In these cases, a full is necessary.

• The GUI suffers from visual glitches in the new MacOS dark mode. This has to do with our Qt theme handling and is not a new problem in , but is expected to be resolved in

Changed configuration options

• can be used to include additional configuration files. Only works inside the file, not inside included files or from command-line. Multiple files may be included. Can be disabled from command- line via . Note that multi-argument commands like will override preceding , i.e.

  as conwaytransport.com.au will still include .

GUI changes

• Block storage can be limited under Preferences, in the Main tab. Undoing this setting requires downloading the full blockchain again. This mode is incompatible with -txindex and -rescan.

External wallet files

The option now accepts full paths instead of requiring wallets to be located in the -walletdir directory.

Newly created wallet format

If is specified with a path that does not exist, it will now create a wallet directory at the specified location (containing a conwaytransport.com.au data file, a conwaytransport.com.au file, and database/log.?????????? files) instead of just creating a data file at the path and storing log files in the parent directory. This should make backing up wallets more straightforward than before because the specified wallet path can just be directly archived without having to look in the parent directory for transaction log files.

For backwards compatibility, wallet paths that are names of existing data files in the directory will continue to be accepted and interpreted the same as before.

Dynamic loading and creation of wallets

Previously, wallets could only be loaded or created at startup, by specifying parameters on the command line or in the conwaytransport.com.au file. It is now possible to load, create and unload wallets dynamically at runtime:

• Existing wallets can be loaded by calling the RPC. The wallet can be specified as file/directory basename (which must be located in the directory), or as an absolute path to a file/directory.
• New wallets can be created (and loaded) by calling the RPC. The provided name must not match a wallet file in the directory or the name of a wallet that is currently loaded.
• Loaded wallets can be unloaded by calling the RPC.

This feature is currently only available through the RPC interface.

Coin selection

Partial spend avoidance

When an address is paid multiple times the coins from those separate payments can be spent separately which hurts privacy due to linking otherwise separate addresses. A new flag has been added (default=false). If enabled, the wallet will always spend existing UTXO to the same address together even if it results in higher fees. If someone were to send coins to an address after it was used, those coins will still be included in future coin selections.

Configuration sections for testnet and regtest

It is now possible for a single configuration file to set different options for different networks. This is done by using sections or by prefixing the option with the network, such as:

If the following options are not in a section, they will only apply to mainnet: , , , , , and . The options to choose a network ( and ) must be specified outside of sections.

‘label’ and ‘account’ APIs for wallet

A new ‘label’ API has been introduced for the wallet. This is intended as a replacement for the deprecated ‘account’ API. The ‘account’ can continue to be used in V by starting bitcoind with the ‘-deprecatedrpc=accounts’ argument, and will be fully removed in V

The label RPC methods mirror the account functionality, with the following functional differences:

• Labels can be set on any address, not just receiving addresses. This functionality was previously only available through the GUI.
• Labels can be deleted by reassigning all addresses using the RPC method.
• There isn’t support for sending transactions from a label, or for determining which label a transaction was sent from.
• Labels do not have a balance.

Here are the changes to RPC methods:

BIP Partially Signed Bitcoin Transactions support

BIP PSBT is an interchange format for Bitcoin transactions that are not fully signed yet, together with relevant metadata to help entities work towards signing it. It is intended to simplify workflows where multiple parties need to cooperate to produce a transaction. Examples include hardware wallets, multisig setups, and CoinJoin transactions.

Overall workflow

Overall, the construction of a fully signed Bitcoin transaction goes through the following steps:

• A Creator proposes a particular transaction to be created. He constructs a PSBT that contains certain inputs and outputs, but no additional metadata.
• For each input, an Updater adds information about the UTXOs being spent by the transaction to the PSBT.
• A potentially other Updater adds information about the scripts and public keys involved in each of the inputs (and possibly outputs) of the PSBT.
• Signers inspect the transaction and its metadata to decide whether they agree with the transaction. They can use amount information from the UTXOs to assess the values and fees involved. If they agree, they produce a partial signature for the inputs for which they have relevant key(s).
• A Finalizer is run for each input to convert the partial signatures and possibly script information into a final and/or .
• An Extractor produces a valid Bitcoin transaction (in network format) from a PSBT for which all inputs are finalized.

Generally, each of the above (excluding Creator and Extractor) will simply add more and more data to a particular PSBT. In a naive workflow, they all have to operate sequentially, passing the PSBT from one to the next, until the Extractor can convert it to a real transaction. In order to permit parallel operation, Combiners can be employed which merge metadata from different PSBTs for the same unsigned transaction.

The names above in bold are the names of the roles defined in BIP They’re useful in understanding the underlying steps, but in practice, software and hardware implementations will typically implement multiple roles simultaneously.

RPCs

• (Creator) is a utility RPC that converts an unsigned raw transaction to PSBT format. It ignores existing signatures.
• (Creator) is a utility RPC that takes a list of inputs and outputs and converts them to a PSBT with no additional information. It is equivalent to calling followed by .
• (Creator, Updater) is a wallet RPC that creates a PSBT with the specified inputs and outputs, adds additional inputs and change to it to balance it out, and adds relevant metadata. In particular, for inputs that the wallet knows about (counting towards its normal or watch-only balance), UTXO information will be added. For outputs and inputs with UTXO information present, key and script information will be added which the wallet knows about. It is equivalent to running , followed by , and .
• (Updater, Signer, Finalizer) is a wallet RPC that takes as input a PSBT, adds UTXO, key, and script data to inputs and outputs that miss it, and optionally signs inputs. Where possible it also finalizes the partial signatures.
• (Finalizer, Extractor) is a utility RPC that finalizes any partial signatures, and if all inputs are finalized, converts the result to a fully signed transaction which can be broadcast with .
• (Combiner) is a utility RPC that implements a Combiner. It can be used at any point in the workflow to merge information added to different versions of the same PSBT. In particular it is useful to combine the output of multiple Updaters or Signers.
• is a diagnostic utility RPC which will show all information in a PSBT in human-readable form, as well as compute its eventual fee if known.

Upgrading non-HD wallets to HD wallets

Since Bitcoin Core , creating new BIP 32 Hierarchical Deterministic wallets has been supported by Bitcoin Core but old non-HD wallets could not be upgraded to HD. Now non-HD wallets can be upgraded to HD using the command line option. This upgrade will result in the all keys in the keypool being marked as used and a new keypool generated. A new backup must be made when this upgrade is performed.

Additionally, can be used to upgraded from a non-split HD chain (all keys generated with ) to a split HD chain (receiving keys generated with and change keys generated with ). When this upgrade occurs, all keys already in the keypool will remain in the keypool to be used until all keys from before the upgrade are exhausted. This is to avoid issues with backups and downgrades when some keys may come from the change key keypool. Users can begin using the new split HD chain keypools by using the RPC to mark all keys in the keypool as used and begin using a new keypool generated from the split HD chain.

HD Master key rotation

A new RPC, , has been introduced which allows users to set a new HD seed or set their own HD seed. This allows for a new HD seed to be used. A new backup must be made when a new HD seed is set.

Low-level RPC changes

• The new RPC can be used to scan the UTXO set for entries that match certain output descriptors. Refer to the output descriptors reference documentation for more details. This call is similar to but does not use a wallet, meaning that the wallet can be disabled at compile or run time. This call is experimental, as such, is subject to changes or removal in future releases.

• The RPC will now accept an array or dictionary (kept for compatibility) for the parameter. This means the order of transaction outputs can be specified by the client.
• The RPC will reject the previously deprecated option.
• now shuffles outputs to improve privacy, so any previously expected behavior with regards to output ordering can no longer be relied upon.
• The new RPC can be used to test acceptance of a transaction to the mempool without adding it.
• JSON transaction decomposition now includes a field which provides the transaction’s exact weight. This is included in REST /rest/tx/ and /rest/block/ endpoints when in json mode. This is also included in (with verbosity=2), , , and RPC commands.
• New field introduced in , , and when verbosity is set to with sub-fields , , and denominated in BTC. This new field deprecates previous fee fields, such as , , and .
• The new RPC returns information about active ZMQ notifications.
• When bitcoin is not started with any options, the name of the default wallet returned by and RPCs is now the empty string instead of . If bitcoin is started with any options, there is no change in behavior, and the name of any wallet is just its string.

• Passing an empty string () as the parameter to , , , RPCs is now an error. Previously, this would fall back to using the default address type. It is still possible to pass null or leave the parameter unset to use the default address type.

• Bare multisig outputs to our keys are no longer automatically treated as incoming payments. As this feature was only available for multisig outputs for which you had all private keys in your wallet, there was generally no use for them compared to single-key schemes. Furthermore, no address format for such outputs is defined, and wallet software can’t easily send to it. These outputs will no longer show up in , , or contribute to your balance, unless they are explicitly watched (using or with hex script argument). also still works for them.

• The RPC method now returns an value, which is always the same as the incorrectly-named value. will be removed in V

• The RPC method now returns an value, which is always the same as the incorrectly-named value. will be removed in V

• Parts of the RPC method have been deprecated and moved to . Clients must transition to using to access this information before upgrading to v The following deprecated fields have moved to and will only be shown with : , , , , , , , , , , , , , .
• is deprecated and will be fully removed in v To use in v, restart bitcoind with . Projects should transition to using and before upgrading to v

Other API changes

• The property in the output has been corrected to

Logging

• The log timestamp format is now ISO (e.g. “TZ”).

• When running bitcoind with but without , logging to stdout is now the default behavior. Setting no longer implicitly disables logging to conwaytransport.com.au Instead, logging to file can be explicitly disabled by setting .

Transaction index changes

The transaction index is now built separately from the main node procedure, meaning the flag can be toggled without a full reindex. If bitcoind is run with on a node that is already partially or fully synced without one, the transaction index will be built in the background and become available once caught up. When switching from running to running without the flag, the transaction index database will not be deleted automatically, meaning it could be turned back on at a later time without a full resync.

Miner block size removed

The option for miners to limit their blocks’ sizes was deprecated in V, and has now been removed. Miners should use the option if they want to limit the weight of their blocks.

Python Support

Support for Python 2 has been discontinued for all test files and tools.

Consensus

Policy

Mining

• # Remove unused variable in SortForBlock (drewx2)
• # Interrupt block generation on shutdown request (promag)

Block and transaction handling

• # Mempool cleanups (sdaftuar)
• # Fix ‘mempool min fee not met’ debug output (Empact)
• # Optimise lock behaviour for GuessVerificationProgress() (jonasschnelli)
• # Drop extra script variable in ProduceSignature (ryanofsky)
• # Stop special-casing phashBlock handling in validation for TBV (TheBlueMatt)
• # Only call NotifyBlockTip when chainActive changes (jamesob)
• # Allow to optional specify the directory for the blocks storage (jonasschnelli)
• # Bugfix: RPC: savemempool: Don’t save until LoadMempool() is finished (jtimon)
• # Make segwit failure due to violation return a error code (maaku)
• # Check for block corruption in ConnectBlock() (sdaftuar)
• # Avoid lock: Call FlushStateToDisk(…) regardless of fCheckForPruning (practicalswift)
• # Enforce and from genesis (sdaftuar)
• # Reduce implementation code inside CScript (sipa)
• # Output values for “min relay fee not met” error (kristapsk)
• # Build txindex in parallel with validation (jimpo)
• # Add compile time checking for ::conwaytransport.com.au runtime locking assertions (practicalswift)
• # Bugfix: the end of a reorged chain is invalid when connect fails (sipa)
• # Fix missing locking in CTxMemPool::check(…) and CTxMemPool::setSanityCheck(…) (practicalswift)
• # Cache witness hash in CTransaction (MarcoFalke)
• # Specialized double-SHA with 64 byte inputs with SSE and AVX2 (sipa)
• # Make reusable base class for auxiliary indices (jimpo)
• # Enable double-SHAforbyte code on bit x86 (sipa)
• # validation: check the specified number of blocks (off-by-one) (kallewoof)
• # Improve coverage of SHA SelfTest code (sipa)
• # validation: count blocks correctly for check level < 3 (kallewoof)
• # SHA implementations based on Intel SHA Extensions (sipa)
• # During IBD, when doing pruning, prune 10% extra to avoid pruning again soon after (luke-jr)
• # chainparams: Update with data from assumed valid chain (MarcoFalke)
• # Remove promiscuousmempoolflags (MarcoFalke)

P2P protocol and network code

• # Extend # (“Do not make it trivial for inbound peers to generate log entries”) to include “version handshake timeout” message (clemtaylor)
• # Move misbehaving logging to net logging category (laanwj)
• # Eventually connect to peers (jonasschnelli)
• # Add test-before-evict discipline to addrman (EthanHeilman)
• # Correct addrman logging (laanwj)
• # add conwaytransport.com.au to DNS seeds (Sjors)
• # Increase signal-to-noise ratio in conwaytransport.com.au by adjusting log level when logging failed non-manual connect():s (practicalswift)
• # Minor accumulated cleanups (tjps)
• # Add missing newlines to debug logging (laanwj)
• # Don’t incorrectly log that REJECT messages are unknown (jnewbery)
• # Serve blocks directly from disk when possible (laanwj)
• # Add option to configure sending of BIP61 notifications (laanwj)
• # Log warning when deprecated network name ‘tor’ is used (wodry)
• # Remove unused interrupt from SendMessages (fanquake)
• # Tighten scope in (skeees)
• # Bucketing INV delays (1 bucket) for incoming connections to hide tx time (naumenkogs)
• # Modified cast in CConman class to work with msvc (sipsorcery)
• # Remove dead service bits code (MarcoFalke)
• # Fixed a race condition when disabling the network (lmanners)
• # Remove the boost/algorithm/string/conwaytransport.com.au dependency (Labs)
• # Thread safety annotations in (skeees)
• # Add missing verification of IPv6 address in CNetAddr::GetIn6Addr(…) (practicalswift)
• # Introduce a maximum size for locators (gmaxwell)
• # Hardcoded seeds update pre branch (laanwj)

Wallet

• # Reduce scope of and locks in listtransactions (promag)
• # Refactor HaveKeys to early return on false result (promag)
• # Disallow abandon of conflicted txes (MarcoFalke)
• # Make CWallet::ListCoins atomic (promag)
• # Only fee-bump non-conflicted/non-confirmed txes (MarcoFalke)
• # Do not un-mark fInMempool on wallet txn if ATMP fails (TheBlueMatt)
• # Disable default fallbackfee on mainnet (jonasschnelli)
• # listreceivedbyaddress Filter Address (NicolasDorier)
• # External wallet files (ryanofsky)
• # Sanitize some wallet serialization (sipa)
• # Unify CWalletTx construction (ryanofsky)
• # Coin Selection with Murch’s algorithm (achow, Xekyo)
• # Change output type globals to members (MarcoFalke)
• # Actually disable BnB when there are preset inputs (achow)
• # Rename account to label where appropriate (ryanofsky)
• # shuffle sendmany recipients ordering (instagibbs)
• # Shuffle transaction inputs before signing (instagibbs)
• # Remove Wallet dependencies from conwaytransport.com.au (jnewbery)
• # Avoid travis lint-include-guards error (ken)
• # importprivkey: hint about importmulti (kallewoof)
• # Make WalletInitInterface and DummyWalletInit private, fix nullptr deref (promag)
• # Initialize to nullptr (practicalswift)
• # Remove redundant lambda function arg in handleTransactionChanged (laanwj)
• # feebumper: discard change outputs below discard rate (instagibbs)
• # introduce ‘label’ API for wallet (jnewbery)
• # Logprint the start of a rescan (jonasschnelli)
• # debug log number of unknown wallet records on load (instagibbs)
• # Refactor to const reference (promag)
• # Add wallets management functions (promag)
• # Deprecate accounts (jnewbery)
• # Make fee settings to be non-static members (MarcoFalke)
• # Do not treat bare multisig outputs as IsMine unless watched (sipa)
• # Make vpwallets usage thread safe (promag)
• # Interrupt rescan on shutdown request (promag)
• # Get rid of ambiguous OutputType::NONE value (ryanofsky)
• # Fix rescanblockchain rpc to properly report progress (Empact)
• # Upgrade path for non-HD wallets to HD (achow)
• # Reset BerkeleyDB handle after connection fails (real-or-random)
• # Add compile time checking for runtime locking assertions (practicalswift)
• # Add Clang thread safety annotations for variables guarded by (practicalswift)
• # RPC - load wallet at runtime (jnewbery)
• # Fix hdmaster-key / seed-key confusion (scripted diff) (jnewbery)
• # Fix incorrect comment for DeriveNewSeed (jnewbery)
• # Use shared pointer to retain wallet instance (promag)
• # Separate IsMine from solvability (sipa)
• # Remove template matching and pseudo opcodes (sipa)
• # Refactor ReserveKeyFromKeyPool for safety (Empact)
• # RPC - create new wallet at runtime (jnewbery)
• # Prevent segfault when sending to unspendable witness (MarcoFalke)
• # Remove getlabeladdress RPC (jnewbery)
• # Add unloadwallet RPC (promag)
• # Unlock spent outputs (promag)
• # Fixups from account API deprecation (jnewbery)
• # Improve handling of INVALID in IsMine (sipa)
• # Moving final scriptSig construction from CombineSignatures to ProduceSignature (PSBT signer logic) (achow)
• # loadwallet shouldn’t create new wallets (jnewbery)
• # ScanforWalletTransactions should mark input txns as dirty (instagibbs)
• # Drop unused pindexRet arg to CMerkleTx::GetDepthInMainChain (Empact)
• # Fix get balance (jnewbery)
• # Decouple wallet version from client version (achow)
• # Fix non-determinism in ParseHDKeypath(…). Avoid using an uninitialized variable in path calculation (practicalswift)
• # Add createwallet “disableprivatekeys” option: a sane mode for watchonly-wallets (jonasschnelli)
• # Introduce assertion to document the assumption that cache and cache_used are always set in tandem (practicalswift)
• # Use destination groups instead of coins in coin select (kallewoof)
• # Fix accidental use of the comma operator (practicalswift)
• # Correctly limit output group size (sdaftuar)
• # Add wallet name to log messages (PierreRochard)
• # Fix backupwallet for multiwallets (domob)
• # assert to ensure accuracy of CMerkleTx::GetBlocksToMaturity (Empact)
• # sum ancestors rather than taking max in output groups (kallewoof)
• # Catch and raise (MarcoFalke)
• # shuffle coins before grouping, where warranted (kallewoof)
• # Always create signatures with Low R values (achow)
• # Additional safety checks in PSBT signer (sipa)
• # couple of walletcreatefundedpsbt fixes (instagibbs)
• # fix walletcreatefundedpsbt deriv paths, add test (instagibbs)

RPC and other APIs

• # Remove deprecated rpc options (jnewbery)
• # Consistently use conwaytransport.com.au instead of push_back(Pair()) (karel-3d) (MarcoFalke)
• # Reject deprecated reserveChangeKey in fundrawtransaction (MarcoFalke)
• # Split part of validateaddress into getaddressinfo (achow)
• # Split signrawtransaction into wallet and non-wallet RPC command (achow)
• # Declare CMutableTransaction a struct in rawtransaction.h (Empact)
• # createmultisig no longer takes addresses (instagibbs)
• # Improve getchaintxstats test coverage (promag)
• # Add child transactions to getrawmempool verbose output (conscott)
• # createrawtransaction: Accept sorted outputs (MarcoFalke)
• # Document RPC method aliasing (ryanofsky)
• # Remove unreachable help conditions in conwaytransport.com.au (lutangar)
• # Add username and ip logging for RPC method requests (GabrielDav)
• # rest: Handle utxo retrieval when ignoring the mempool (romanz)
• # Adjust ifdef to avoid unreachable code (practicalswift)
• # Add testmempoolaccept (MarcoFalke)
• # Drop redundant testing of signrawtransaction prevtxs args (Empact)
• # Allow for aborting rescans in the GUI (achow)
• # Expose a transaction’s weight via RPC (TheBlueMatt)
• # Adds a functional test to validate the transaction version number in the RPC output (Labs)
• # Introduced a new structure that aggregates all sub-field fee types denominated in BTC (mryandao)
• # p2wsh and p2sh-p2wsh address in decodescript (fivepiece)
• # Remove Safe mode (achow, laanwj)
• # Reduce lock in listunspent (promag)
• # New -includeconf argument for including external configuration files (kallewoof)
• # Introduce getblockstats to plot things (jtimon)
• # Remove the need to include rpc/conwaytransport.com.au in order to put under test (Empact)
• # cli: Ignore libevent warnings (theuni)
• # Avoid “duplicate” return value for invalid submitblock (TheBlueMatt)
• # Add new “getzmqnotifications” method (domob)
• # Update createmultisig RPC to support segwit (ajtowns)
• # Add scantxoutset RPC method (jonasschnelli)
• # BIP PSBT Serializations and RPCs (achow)
• # Support output descriptors in scantxoutset (sipa)
• # Use pushKV in some new PSBT RPCs (domob)
• # Replace median fee rate with feerate percentiles in getblockstats (marcinja)
• # Bugfixes for BIP combining and deserialization (achow)
• # Fix PSBT deserialization of 0-input transactions (achow)

GUI

• # Fix Windows build errors introduced in # (practicalswift)
• # Remove redundant locks (practicalswift)
• # Initialize members in WalletModel (MarcoFalke)
• # Bugfix: respect user defined configuration file (-conf) in QT settings (jonasschnelli)
• # navigate to transaction history page after send (Sjors)
• # Show a transaction’s virtual size in its details dialog (dooglus)
• # Improved “custom fee” explanation in tooltip (randolf)
• # Set modal overlay hide button as default (promag)
• # Remove TransactionTableModel::TxIDRole (promag)
• # Add support to search the address book (promag)
• # Avoid querying unnecessary model data when filtering transactions (promag)
• # remove “new” button during receive-mode in addressbook (jonasschnelli)
• # Qt5: Warning users about invalid-BIP21 URI bitcoin:// (krab)
• # Multiwallet for the GUI (jonasschnelli)
• # Remove unused method setupAmountWidget(…) (practicalswift)
• # do not truncate .dat extension for wallets in gui (instagibbs)
• # make clean removes files (Sjors)
• # Don’t log to console by default (laanwj)
• # fixes broken link on readme (marcoagner)
• # Initialize non-static class members that were previously neither initialized where defined nor in constructor (practicalswift)
• # Improve sendcoinsdialog readability (marcoagner)
• # Add proxy icon in statusbar (mess)
• # Satoshi unit (GreatSock)