bitcoin/doc/release-notes.md

(note: this is a temporary file, to be added-to by anybody, and moved to release-notes at release time)

Bitcoin Core version version is now available from:

https://bitcoincore.org/bin/bitcoin-core-*version*/

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:

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, 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. Upgrading directly from 0.7.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 0.15 and then decide to switch back to any older version, you will need to run the old release with the -reindex-chainstate 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.

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 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.

Notable changes

Mining

• Calls to getblocktemplate will fail if the segwit rule is not 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

• A warning is printed if an unrecognized section name is used in the configuration file. Recognized sections are [test], [main], and [regtest].

• Four new options are available for configuring the maximum number of 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 for details.

• The enablebip61 option (introduced in Bitcoin Core 0.17.0) is used to toggle sending of BIP 61 reject messages. Reject messages have no use case on the P2P network and are only logged for debugging by most network nodes. The option will now by default be off for improved privacy and security as well as reduced upload usage. The option can explicitly be turned on for local-network debugging purposes.

• The rpcallowip option can no longer be used to automatically listen on all network interfaces. Instead, the rpcbind parameter must also 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).

• The rpcpassword option now causes a startup error if the password 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.

• The whitelistforcerelay option is used to relay transactions from 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 letting the Bitcoin Core project know about their use-case, as this feature could be deprecated in the future).

Documentation

• A new short document 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.

• A new document about the bitcoin.conf file describes how to use it to configure Bitcoin Core.

• A new document introduces Bitcoin Core's BIP174 Partially-Signed Bitcoin Transactions (PSBT) 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.

• The output script descriptor 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 the scantxoutset RPC and is expected to be adapted to other RPCs and to the underlying wallet structure.

Build system changes

• A new --disable-bip70 option may be passed to ./configure to 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.

Deprecated or removed RPCs

• The signrawtransaction RPC is removed after being deprecated and hidden behind a special configuration option in version 0.17.0.

• The 'account' API is removed after being deprecated in v0.17. The 'label' API was introduced in v0.17 as a replacement for accounts. See the release notes from v0.17 for a full description of the changes from the 'account' API to the 'label' API.

• The addwitnessaddress RPC is removed after being deprecated in version 0.13.0.

• The wallet's generate RPC method is deprecated and will be fully removed in a subsequent 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.

New RPCs

• A new getnodeaddresses RPC returns peer addresses known to this node. It may be used to find nodes to connect to without using a DNS seeder.

• A new listwalletdir RPC returns a list of wallets in the wallet directory (either the default wallet directory or the directory configured by the -walletdir parameter).

Updated RPCs

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

• The getpeerinfo RPC now returns an additional minfeefilter field set to 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.

• The mempool RPCs, such as getrawmempool with verbose=true, now 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 settxfee RPC previously silently ignored attempts to set the fee below the allowed minimums. It now prints a warning. The special value of "0" may still be used to request the minimum value.

• The getaddressinfo RPC now provides an ischange field indicating whether the wallet used the address in a change output.

• The importmulti RPC has been updated to support P2WSH, P2WPKH, P2SH-P2WPKH, and P2SH-P2WSH. Requests for P2WSH and P2SH-P2WSH accept an additional witnessscript parameter.

• The importmulti RPC now returns an additional warnings field for each request with an array of strings explaining when fields are being ignored or are inconsistent, if there are any.

• The getaddressinfo RPC now returns an additional solvable boolean field 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.

• The getaddressinfo, listunspent, and scantxoutset RPCs now 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.

• The importprivkey RPC will preserve previously-set labels for addresses or 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.

• See the Mining section for changes to getblocktemplate.

Graphical User Interface (GUI)

• A new Window menu is added alongside the existing File, Settings, and Help menus. Several items from the other menus that opened new windows have been moved to this new Window menu.

• In the Send tab, the checkbox for "pay only the required fee" has been 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.

• In the Overview tab, the watch-only balance will be the only balance shown if the wallet was created using the createwallet RPC and the disable_private_keys parameter was set to true.

• The launch-on-startup option is no longer available on macOS if 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)

Low-level changes

RPC

• The submitblock RPC previously returned the reason a rejected block 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.

• A new submitheader RPC allows submitting block headers independently from their block. This is likely only useful for testing.

Configuration

• The -usehd configuration option was removed in version 0.16. From that version onwards, all new wallets created are hierarchical deterministic wallets. This release makes specifying -usehd an invalid configuration option.

Changes for particular platforms

• On macOS, Bitcoin Core now opts out of application CPU throttling ("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.

Credits

Thanks to everyone who directly contributed to this release:

As well as everyone that helped translating on Transifex.