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After branching off for a major version release of Bitcoin Core, use this template to create the initial release notes draft.
The release notes draft is a temporary file that can be added to by anyone. See /doc/developer-notes.md#release-notes for the process.
Create the draft, named "version Release Notes Draft" (e.g. "0.20.0 Release Notes Draft"), as a collaborative wiki in:
https://github.com/bitcoin-core/bitcoin-devwiki/wiki/
Before the final release, move the notes back to this git repository.
version Release Notes Draft
Bitcoin Core version version is now available from:
https://bitcoincore.org/bin/bitcoin-core-*version*/
This release includes 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 in some cases), then run the
installer (on Windows) or just copy over /Applications/Bitcoin-Qt
(on Mac)
or bitcoind
/bitcoin-qt
(on Linux).
Upgrading directly from a version of Bitcoin Core that has reached its EOL is possible, but it might take some time if the data directory needs to be migrated. Old wallet versions of Bitcoin Core are generally supported.
Compatibility
During this release cycle, work has been done to ensure that the codebase is fully compatible with C++17. The intention is to begin using C++17 features starting with the 0.22.0 release. This means that a compiler that supports C++17 will be required to compile 0.22.0.
Bitcoin Core is supported and extensively tested on operating systems using the Linux kernel, macOS 10.12+, and Windows 7 and newer. Bitcoin Core should also work on most other Unix-like systems but is not as frequently tested on them. It is not recommended to use Bitcoin Core on unsupported systems.
From Bitcoin Core 0.20.0 onwards, macOS versions earlier than 10.12 are no longer supported. Additionally, Bitcoin Core does not yet change appearance when macOS "dark mode" is activated.
Notable changes
P2P and network changes
- The mempool now tracks whether transactions submitted via the wallet or RPCs
have been successfully broadcast. Every 10-15 minutes, the node will try to
announce unbroadcast transactions until a peer requests it via a
getdata
message or the transaction is removed from the mempool for other reasons. The node will not track the broadcast status of transactions submitted to the node using P2P relay. This version reduces the initial broadcast guarantees for wallet transactions submitted via P2P to a node running the wallet. (#18038)
Updated RPCs
-
getmempoolinfo
now returns an additionalunbroadcastcount
field. The mempool tracks locally submitted transactions until their initial broadcast is acknowledged by a peer. This field returns the count of transactions waiting for acknowledgement. -
Mempool RPCs such as
getmempoolentry
andgetrawmempool
withverbose=true
now return an additionalunbroadcast
field. This indicates whether initial broadcast of the transaction has been acknowledged by a peer.getmempoolancestors
andgetmempooldescendants
are also updated. -
The
bumpfee
,fundrawtransaction
,sendmany
,sendtoaddress
, andwalletcreatefundedpsbt
RPC commands have been updated to include two new fee estimation methods "BTC/kB" and "sat/B". The target is the fee expressed explicitly in the given form. Note that use of this feature will trigger BIP 125 (replace-by-fee) opt-in. (#11413) -
In addition, the
estimate_mode
parameter is now case insensitive for all of the above RPC commands. (#11413) -
The
bumpfee
command now usesconf_target
rather thanconfTarget
in the options. (#11413) -
The
getpeerinfo
RPC no longer returns thebanscore
field unless the configuration option-deprecatedrpc=banscore
is used. Thebanscore
field will be fully removed in the next major release. (#19469) -
The
walletcreatefundedpsbt
RPC call will now fail withInsufficient funds
when inputs are manually selected but are not enough to cover the outputs and fee. Additional inputs can automatically be added through the newadd_inputs
option. (#16377) -
The
fundrawtransaction
RPC now supportsadd_inputs
option that whenfalse
prevents adding more inputs if necessary and consequently the RPC fails.
Changes to Wallet or GUI related RPCs can be found in the GUI or Wallet section below.
New RPCs
- The
getindexinfo
RPC returns the actively running indices of the node, including their current sync status and height. It also accepts anindex_name
to specify returning only the status of that index. (#19550)
Build System
Updated settings
-
The
-banscore
configuration option, which modified the default threshold for disconnecting and discouraging misbehaving peers, has been removed as part of changes in 0.20.1 and in this release to the handling of misbehaving peers. Refer to "Changes regarding misbehaving peers" in the 0.20.1 release notes for details. (#19464) -
The
-debug=db
logging category, which was deprecated in 0.20 and replaced by-debug=walletdb
to distinguish it fromcoindb
, has been removed. (#19202) -
A
download
permission has been extracted from thenoban
permission. For compatibility,noban
implies thedownload
permission, but this may change in future releases. Refer to the help of the affected settings-whitebind
and-whitelist
for more details. (#19191) -
Netmasks that contain 1-bits after 0-bits (the 1-bits are not contiguous on the left side, e.g. 255.0.255.255) are no longer accepted. They are invalid according to RFC 4632.
Changes to Wallet or GUI related settings can be found in the GUI or Wallet section below.
Tools and Utilities
-
A new
bitcoin-cli -generate
command, equivalent to RPCgeneratenewaddress
followed bygeneratetoaddress
, can generate blocks for command line testing purposes. This is a client-side version of the formergenerate
RPC. See the help for details. (#19133) -
The
bitcoin-cli -getinfo
command now displays the wallet name and balance for each of the loaded wallets when more than one is loaded (e.g. in multiwallet mode) and a wallet is not specified with-rpcwallet
. (#18594)
New settings
Wallet
-
Backwards compatibility has been dropped for two
getaddressinfo
RPC deprecations, as notified in the 0.20 release notes. The deprecatedlabel
field has been removed as well as the deprecatedlabels
behavior of returning a JSON object containingname
andpurpose
key-value pairs. Since 0.20, thelabels
field returns a JSON array of label names. (#19200) -
To improve wallet privacy, the frequency of wallet rebroadcast attempts is reduced from approximately once every 15 minutes to once every 12-36 hours. To maintain a similar level of guarantee for initial broadcast of wallet transactions, the mempool tracks these transactions as a part of the newly introduced unbroadcast set. See the "P2P and network changes" section for more information on the unbroadcast set. (#18038)
-
The wallet can create a transaction without change even when the keypool is empty. Previously it failed. (#17219)
-
The
-salvagewallet
startup option has been removed. A newsalvage
command has been added to thebitcoin-wallet
tool which performs the salvage operations that-salvagewallet
did. (#18918)
Experimental Descriptor Wallets
Please note that Descriptor Wallets are still experimental and not all expected functionality is available. Additionally there may be some bugs and current functions may change in the future. Bugs and missing functionality can be reported to the issue tracker.
0.21 introduces a new type of wallet - Descriptor Wallets. Descriptor Wallets store scriptPubKey information using descriptors. This is in contrast to the Legacy Wallet structure where keys are used to generate scriptPubKeys and addresses. Because of this shift to being script based instead of key based, many of the confusing things that Legacy Wallets do are not possible with Descriptor Wallets. Descriptor Wallets use a definition of "mine" for scripts which is simpler and more intuitive than that used by Legacy Wallets. Descriptor Wallets also uses different semantics for watch-only things and imports.
As Descriptor Wallets are a new type of wallet, their introduction does not affect existing wallets. Users who already have a Bitcoin Core wallet can continue to use it as they did before without any change in behavior. Newly created Legacy Wallets (which is the default type of wallet) will behave as they did in previous versions of Bitcoin Core.
The differences between Descriptor Wallets and Legacy Wallets are largely limited to non user facing things. They are intended to behave similarly except for the import/export and watchonly functionality as described below.
Creating Descriptor Wallets
Descriptor Wallets are not created by default. They must be explicitly created using the
createwallet
RPC or via the GUI. A descriptors
option has been added to createwallet
.
Setting descriptors
to true
will create a Descriptor Wallet instead of a Legacy Wallet.
In the GUI, a checkbox has been added to the Create Wallet Dialog to indicate that a Descriptor Wallet should be created.
Without those options being set, a Legacy Wallet will be created instead. Additionally the Default Wallet created upon first startup of Bitcoin Core will be a Legacy Wallet.
IsMine
Semantics
IsMine
refers to the function used to determine whether a script belongs to the wallet.
This is used to determine whether an output belongs to the wallet. IsMine
in Legacy Wallets
returns true if the wallet would be able to sign an input that spends an output with that script.
Since keys can be involved in a variety of different scripts, this definition for IsMine
can
lead to many unexpected scripts being considered part of the wallet.
With Descriptor Wallets, descriptors explicitly specify the set of scripts that are owned by
the wallet. Since descriptors are deterministic and easily enumerable, users will know exactly
what scripts the wallet will consider to belong to it. Additionally the implementation of IsMine
in Descriptor Wallets is far simpler than for Legacy Wallets. Notably, in Legacy Wallets, IsMine
allowed for users to take one type of address (e.g. P2PKH), mutate it into another address type
(e.g. P2WPKH), and the wallet would still detect outputs sending to the new address type
even without that address being requested from the wallet. Descriptor Wallets does not
allow for this and will only watch for the addresses that were explicitly requested from the wallet.
These changes to IsMine
will make it easier to reason about what scripts the wallet will
actually be watching for in outputs. However for the vast majority of users, this change is
largely transparent and will not have noticeable effect.
Imports and Exports
In Legacy Wallets, raw scripts and keys could be imported to the wallet. Those imported scripts
and keys are treated separately from the keys generated by the wallet. This complicates the IsMine
logic as it has to distinguish between spendable and watchonly.
Descriptor Wallets handle importing scripts and keys differently. Only complete descriptors can be
imported. These descriptors are then added to the wallet as if it were a descriptor generated by
the wallet itself. This simplifies the IsMine
logic so that it no longer has to distinguish
between spendable and watchonly. As such, the watchonly model for Descriptor Wallets is also
different and described in more detail in the next section.
To import into a Descriptor Wallet, a new importdescriptors
RPC has been added that uses a syntax
similar to that of importmulti
.
As Legacy Wallets and Descriptor Wallets use different mechanisms for storing and importing scripts and keys the existing import RPCs have been disabled for descriptor wallets. New export RPCs for Descriptor Wallets have not yet been added.
The following RPCs are disabled for Descriptor Wallets:
- importprivkey
- importpubkey
- importaddress
- importwallet
- dumpprivkey
- dumpwallet
- importmulti
- addmultisigaddress
- sethdseed
Watchonly Wallets
A Legacy Wallet contains both private keys and scripts that were being watched.
Those watched scripts would not contribute to your normal balance. In order to see the watchonly
balance and to use watchonly things in transactions, an include_watchonly
option was added
to many RPCs that would allow users to do that. However it is easy to forget to include this option.
Descriptor Wallets move to a per-wallet watchonly model. Instead an entire wallet is considered to be watchonly depending on whether it was created with private keys disabled. This eliminates the need to distinguish between things that are watchonly and things that are not within a wallet itself.
This change does have a caveat. If a Descriptor Wallet with private keys enabled has
a multiple key descriptor without all of the private keys (e.g. multi(...)
with only one private key),
then the wallet will fail to sign and broadcast transactions. Such wallets would need to use the PSBT
workflow but the typical GUI Send, sendtoaddress
, etc. workflows would still be available, just
non-functional.
This issue is worsened if the wallet contains both single key (e.g. wpkh(...)
) descriptors and such
multiple key descriptors as some transactions could be signed and broadast and others not. This is
due to some transactions containing only single key inputs, while others would contain both single
key and multiple key inputs, depending on which are available and how the coin selection algorithm
selects inputs. However this is not considered to be a supported use case; multisigs
should be in their own wallets which do not already have descriptors. Although users cannot export
descriptors with private keys for now as explained earlier.
BIP 44/49/84 Support
The change to using descriptors changes the default derivation paths used by Bitcoin Core to adhere to BIP 44/49/84. Descriptors with different derivation paths can be imported without issue.
Wallet RPC changes
- The
upgradewallet
RPC replaces the-upgradewallet
command line option. (#15761) - The
settxfee
RPC will fail if the fee was set higher than the-maxtxfee
command line setting. The wallet will already fail to create transactions with fees higher than-maxtxfee
. (#18467)
GUI changes
- The GUI Peers window no longer displays a "Ban Score" field. This is part of changes in 0.20.1 and in this release to the handling of misbehaving peers. Refer to "Changes regarding misbehaving peers" in the 0.20.1 release notes for details. (#19512)
Low-level changes
RPC
- To make RPC
sendtoaddress
more consistent withsendmany
the following errorsendtoaddress
codes were changed from-4
to-6
:- Insufficient funds
- Fee estimation failed
- Transaction has too long of a mempool chain
Tests
Credits
Thanks to everyone who directly contributed to this release:
As well as to everyone that helped with translations on Transifex.