release-notes-0.18.0.md raw

Bitcoin Core version 0.18.0 is now available from:

<https://bitcoincore.org/bin/bitcoin-core-0.18.0/>

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

Please report bugs using the issue tracker at GitHub:

<https://github.com/bitcoin/bitcoin/issues>

To receive security and update notifications, please subscribe to:

<https://bitcoincore.org/en/list/announcements/join/>

How to Upgrade ==============

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 /Applications/Bitcoin-Qt (on Mac) or bitcoind/bitcoin-qt (on Linux).

The first time you run version 0.15.0 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 0.8.0 and there is no automatic upgrade code from before version 0.8 to version 0.15.0 or later. Upgrading directly from 0.7.x and earlier without redownloading the blockchain is not supported. However, as usual, old wallet versions are still supported.

Compatibility ==============

Bitcoin Core is supported and extensively tested on operating systems using the Linux kernel, macOS 10.10+, and Windows 7 and newer. It is not recommended to use Bitcoin Core on unsupported systems.

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

From 0.17.0 onwards, macOS <10.10 is no longer supported. 0.17.0 is built using Qt 5.9.x, which doesn't support versions of macOS older than 10.10. Additionally, Bitcoin Core does not yet change appearance when macOS "dark mode" is activated.

In addition to previously-supported CPU platforms, this release's pre-compiled distribution also provides binaries for the RISC-V platform.

If you are using the systemd unit configuration file located at contrib/init/bitcoind.service, it has been changed to use /var/lib/bitcoind as the data directory instead of ~bitcoin/.bitcoin. When switching over to the new configuration file, please make sure that the filesystem on which /var/lib/bitcoind will exist has enough space (check using df -h /var/lib/bitcoind), and optionally copy over your existing data directory. See the [systemd init file section](#systemd-init-file) for more details.

Known issues ============

Wallet GUI

For advanced users who have both (1) enabled coin control features, and (2) are using multiple wallets loaded at the same time: The coin control input selection dialog can erroneously retain wrong-wallet state when switching wallets using the dropdown menu. For now, it is recommended not to use coin control features with multiple wallets loaded.

Notable changes ===============

Mining

specified. Calling getblocktemplate without segwit specified is almost certainly a misconfiguration since doing so results in lower rewards for the miner. Failed calls will produce an error message describing how to enable the segwit rule.

Configuration option changes

configuration file. Recognized sections are [test], [main], and [regtest].

messages that ZMQ will queue in memory (the "high water mark") before dropping additional messages. The default value is 1,000, the same as was used for previous releases. See the [ZMQ documentation](https://github.com/bitcoin/bitcoin/blob/master/doc/zmq.md#usage) for details.

on all network interfaces. Instead, the rpcbind parameter must be used to specify the IP addresses to listen on. Listening for RPC commands over a public network connection is insecure and should be disabled, so a warning is now printed if a user selects such a configuration. If you need to expose RPC in order to use a tool like Docker, ensure you only bind RPC to your localhost, e.g. `docker run [...] -p 127.0.0.1:8332:8332 (this is an extra :8332` over the normal Docker port specification).

set in the configuration file contains a hash character (#), as it's ambiguous whether the hash character is meant for the password or as a comment.

whitelisted peers even when not accepted to the mempool. This option now defaults to being off, so that changes in policy and disconnect/ban behavior will not cause a node that is whitelisting another to be dropped by peers. Users can still explicitly enable this behavior with the command line option (and may want to consider contacting the Bitcoin Core project to let us know about their use-case, as this feature could be deprecated in the future).

systemd init file

The systemd init file (contrib/init/bitcoind.service) has been changed to use /var/lib/bitcoind as the data directory instead of ~bitcoin/.bitcoin. This change makes Bitcoin Core more consistent with other services, and makes the systemd init config more consistent with existing Upstart and OpenRC configs.

The configuration, PID, and data directories are now completely managed by systemd, which will take care of their creation, permissions, etc. See `systemd.exec(5)` for more details.

When using the provided init files under contrib/init, overriding the datadir option in /etc/bitcoin/bitcoin.conf will have no effect. This is because the command line arguments specified in the init files take precedence over the options specified in /etc/bitcoin/bitcoin.conf.

Documentation

about the JSON-RPC interface describes cases where the results of an RPC might contain inconsistencies between data sourced from different subsystems, such as wallet state and mempool state. A note is added to the REST interface documentation indicating that the same rules apply.

documentation](https://github.com/bitcoin/bitcoin/blob/master/doc/JSON-RPC-interface.md) about how to secure this interface.

about the bitcoin.conf file describes how to use it to configure Bitcoin Core.

Bitcoin Transactions (PSBT)](https://github.com/bitcoin/bitcoin/blob/master/doc/psbt.md) interface, which is used to allow multiple programs to collaboratively work to create, sign, and broadcast new transactions. This is useful for offline (cold storage) wallets, multisig wallets, coinjoin implementations, and many other cases where two or more programs need to interact to generate a complete transaction.

descriptor](https://github.com/bitcoin/bitcoin/blob/master/doc/descriptors.md) documentation has been updated with information about new features in this still-developing language for describing the output scripts that a wallet or other program wants to receive notifications for, such as which addresses it wants to know received payments. The language is currently used in multiple new and updated RPCs described in these release notes and is expected to be adapted to other RPCs and to the underlying wallet structure.

Build system changes

prevent Bitcoin-Qt from being built with support for the BIP70 payment protocol or from linking libssl. As the payment protocol has exposed Bitcoin Core to libssl vulnerabilities in the past, builders who don't need BIP70 support are encouraged to use this option to reduce their exposure to future vulnerabilities.

increased from 5.2 to 5.5.1 (the [depends system](https://github.com/bitcoin/bitcoin/blob/master/depends/README.md) provides 5.9.7)

New RPCs

be used to find nodes to connect to without using a DNS seeder.

(either the default wallet directory or the directory configured by the -walletdir parameter).

it returns an array of the currently active commands and how long they've been running.

output descriptor.

it, including its computed checksum.

multiple PSBTs must have different inputs. The resulting PSBT will contain every input and output from all of the PSBTs. Any signatures provided in any of the PSBTs will be dropped.

the PSBT contains and the next steps that need to be taken in order to complete the transaction. For each input of a PSBT, analyzepsbt provides information about what information is missing for that input, including whether a UTXO needs to be provided, what pubkeys still need to be provided, which scripts need to be provided, and what signatures are still needed. Every input will also list which role is needed to complete that input, and analyzepsbt will also list the next role in general needed to complete the PSBT. analyzepsbt will also provide the estimated fee rate and estimated virtual size of the completed transaction if it has enough information to do so.

(UTXOs) to find the outputs being spent by the partial transaction. PSBTs need to have the UTXOs being spent to be provided because the signing algorithm requires information from the UTXO being spent. For segwit inputs, only the UTXO itself is necessary. For non-segwit outputs, the entire previous transaction is needed so that signers can be sure that they are signing the correct thing. Unfortunately, because the UTXO set only contains UTXOs and not full transactions, utxoupdatepsbt will only add the UTXO for segwit inputs.

Updated RPCs

Note: some low-level RPC changes mainly useful for testing are described in the Low-level Changes section below.

the peer's BIP133 fee filter. You can use this to detect that you have peers that are willing to accept transactions below the default minimum relay fee.

return an additional "bip125-replaceable" value indicating whether the transaction (or its unconfirmed ancestors) opts-in to asking nodes and miners to replace it with a higher-feerate transaction spending any of the same inputs.

the allowed minimums. It now prints a warning. The special value of "0" may still be used to request the minimum value.

the wallet used the address in a change output.

and P2SH-P2WSH. Requests for P2WSH and P2SH-P2WSH accept an additional witnessscript parameter.

request with an array of strings explaining when fields are being ignored or are inconsistent, if there are any.

when Bitcoin Core knows enough about the address's scriptPubKey, optional redeemScript, and optional witnessScript in order for the wallet to be able to generate an unsigned input spending funds sent to that address.

return an additional desc field that contains an output descriptor containing all key paths and signing information for the address (except for the private key). The desc field is only returned for getaddressinfo and listunspent when the address is solvable.

public keys corresponding to the private key being imported. For example, if you imported a watch-only address with the label "cold wallet" in earlier releases of Bitcoin Core, subsequently importing the private key would default to resetting the address's label to the default empty-string label (""). In this release, the previous label of "cold wallet" will be retained. If you optionally specify any label besides the default when calling importprivkey, the new label will be applied to the address.

when a block was never assembled via RPC on this node.

unspent UTXO set for a transaction. The remaining behaviors are as follows: 1. If a blockhash is provided, check the corresponding block. 2. If no blockhash is provided, check the mempool. 3. If no blockhash is provided but txindex is enabled, also check txindex.

the wallet is fully unloaded.

"desc" parameter can be provided instead of the "scriptPubKey" in a request, as well as an optional range for ranged descriptors to specify the start and end of the range to import. Descriptors with key origin information imported through importmulti will have their key origin information stored in the wallet for use with creating PSBTs. More information about descriptors can be found here.

witnessScript, the witness script in the case of a P2WSH or P2SH-P2WSH output.

to create a blank wallet. Blank wallets do not have any keys or HD seed. They cannot be opened in software older than 0.18. Once a blank wallet has a HD seed set (by using sethdseed) or private keys, scripts, addresses, and other watch only things have been imported, the wallet is no longer blank and can be opened in 0.17.x. Encrypting a blank wallet will also set a HD seed for it.

Deprecated or removed RPCs

behind a special configuration option in version 0.17.0.

'label' API was introduced in v0.17 as a replacement for accounts. See the [release notes from v0.17](https://github.com/bitcoin/bitcoin/blob/master/doc/release-notes/release-notes-0.17.0.md#label-and-account-apis-for-wallet) for a full description of the changes from the 'account' API to the 'label' API.

0.16.0.

major version. This RPC is only used for testing, but its implementation reached across multiple subsystems (wallet and mining), so it is being deprecated to simplify the wallet-node interface. Projects that are using generate for testing purposes should transition to using the generatetoaddress RPC, which does not require or use the wallet component. Calling generatetoaddress with an address returned by the getnewaddress RPC gives the same functionality as the old generate RPC. To continue using generate in this version, restart bitcoind with the -deprecatedrpc=generate configuration option.

deprecated and moved to getaddressinfo. The following deprecated fields have moved to getaddressinfo: ismine, iswatchonly, script, hex, pubkeys, sigsrequired, pubkey, embedded, iscompressed, label, timestamp, hdkeypath, hdmasterkeyid.

and getaddressinfo RPC methods. This field was confusing since it referred to public keys using their P2PKH address. Clients should use the embedded.address field for P2SH or P2WSH wrapped addresses, and pubkeys for inspecting multisig participants.

REST changes

hash of the block in the current best blockchain based on its height (how many blocks it is after the Genesis Block).

Graphical User Interface (GUI)

Help menus. Several items from the other menus that opened new windows have been moved to this new Window menu.

removed. Instead, the user can simply decrease the value in the Custom Feerate field all the way down to the node's configured minimum relay fee.

shown if the wallet was created using the createwallet RPC and the disable_private_keys parameter was set to true.

compiled with macosx min version greater than 10.11 (use CXXFLAGS="-mmacosx-version-min=10.11" CFLAGS="-mmacosx-version-min=10.11" for setting the deployment sdk version)

Tools

Core's other executables. Without needing to use any RPCs, this tool can currently create a new wallet file or display some basic information about an existing wallet, such as whether the wallet is encrypted, whether it uses an HD seed, how many transactions it contains, and how many address book entries it has.

Planned changes ===============

This section describes planned changes to Bitcoin Core that may affect other Bitcoin software and services.

generating P2SH-wrapped segwit addresses when users want to receive payments. These addresses are backwards compatible with all widely-used software. Starting with Bitcoin Core 0.20 (expected about a year after 0.18), Bitcoin Core will default to native segwit addresses (bech32) that provide additional fee savings and other benefits. Currently, many wallets and services already support sending to bech32 addresses, and if the Bitcoin Core project sees enough additional adoption, it will instead default to bech32 receiving addresses in Bitcoin Core 0.19 (approximately November 2019). P2SH-wrapped segwit addresses will continue to be provided if the user requests them in the GUI or by RPC, and anyone who doesn’t want the update will be able to configure their default address type. (Similarly, pioneering users who want to change their default now may set the addresstype=bech32 configuration option in any Bitcoin Core release from 0.16.0 up.)

Deprecated P2P messages

case on the P2P network and are only logged for debugging by most network nodes. Furthermore, they increase bandwidth and can be harmful for privacy and security. It has been possible to disable BIP 61 messages since v0.17 with the -enablebip61=0 option. BIP 61 messages will be disabled by default in a future version, before being removed entirely.

Low-level changes =================

This section describes RPC changes mainly useful for testing, mostly not relevant in production. The changes are mentioned for completeness.

RPC

was invalid the first time it processed that block, but returned a generic "duplicate" rejection message on subsequent occasions it processed the same block. It now always returns the fundamental reason for rejecting an invalid block and only returns "duplicate" for valid blocks it has already accepted.

from their block. This is likely only useful for testing.

RPCs have been modified so that they also optionally accept a witnessScript, the witness script in the case of a P2WSH or P2SH-P2WSH output. This is compatible with the change to listunspent.

bip32derivs parameter is set to true but the key metadata for a public key has not been updated yet, then that key will have a derivation path as if it were just an independent key (i.e. no derivation path and its master fingerprint is itself).

Configuration

that version onwards, all new wallets created are hierarchical deterministic wallets. This release makes specifying -usehd an invalid configuration option.

Network

for misbehavior (e.g. sending invalid data) to reconnect to your node if you have unused incoming connection slots. If your slots fill up, a misbehaving node will be disconnected to make room for nodes without a history of problems (unless the misbehaving node helps your node in some other way, such as by connecting to a part of the Internet from which you don't have many other peers). Previously, Bitcoin Core banned the IP addresses of misbehaving peers for a period of time (default of 1 day); this was easily circumvented by attackers with multiple IP addresses. If you manually ban a peer, such as by using the setban RPC, all connections from that peer will still be rejected.

Wallet

seed is available. For unencrypted wallets this will occur on wallet loading. For encrypted wallets this will occur the first time the wallet is unlocked.

software. Instead such wallets will be completely unloaded and reloaded to achieve the same effect.

(HWI) scripts that allow command-line users to use several popular hardware key management devices with Bitcoin Core. See their [project page](https://github.com/bitcoin-core/HWI#readme) for details.

Security

OpenSSL to Bitcoin Core's own implementation, although entropy gathered by Bitcoin Core is fed out to OpenSSL and then read back in when the program needs strong randomness. This moves Bitcoin Core a little closer to no longer needing to depend on OpenSSL, a dependency that has caused security issues in the past. The new implementation gathers entropy from multiple sources, including from hardware supporting the rdseed CPU instruction.

Changes for particular platforms

("app nap") during initial blockchain download, when catching up from over 100 blocks behind the current chain tip, or when reindexing chain data. This helps prevent these operations from taking an excessively long time because the operating system is attempting to conserve power.

0.18.0 change log =================

Consensus

Mining

Block and transaction handling

P2P protocol and network code

Wallet

RPC and other APIs

GUI

Build system

Tests and QA

Platform support

Miscellaneous

Documentation

Credits =======

Thanks to everyone who directly contributed to this release:

As well as everyone that helped translating on Transifex.