READ THE CODE

Inside Bitcoin

The code behind the network, with room to understand it.

Stable release v32.1bitcoin/bitcoin · f0de87f04062 ↗3,020 source files · 47.5 MB stored on the server440 file guides

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1Bitcoin Core version 28.0 is now available from:
2
3  <https://bitcoincore.org/bin/bitcoin-core-28.0/>
4
5This release includes new features, various bug fixes and performance
6improvements, as well as updated translations.
7
8Please report bugs using the issue tracker at GitHub:
9
10  <https://github.com/bitcoin/bitcoin/issues>
11
12To receive security and update notifications, please subscribe to:
13
14  <https://bitcoincore.org/en/list/announcements/join/>
15
16How to Upgrade
17==============
18
19If you are running an older version, shut it down. Wait until it has completely
20shut down (which might take a few minutes in some cases), then run the
21installer (on Windows) or just copy over `/Applications/Bitcoin-Qt` (on macOS)
22or `bitcoind`/`bitcoin-qt` (on Linux).
23
24Upgrading directly from a version of Bitcoin Core that has reached its EOL is
25possible, but it might take some time if the data directory needs to be migrated. Old
26wallet versions of Bitcoin Core are generally supported.
27
28Running Bitcoin Core binaries on macOS requires self signing.
29```
30cd /path/to/bitcoin-28.0/bin
31xattr -d com.apple.quarantine bitcoin-cli bitcoin-qt bitcoin-tx bitcoin-util bitcoin-wallet bitcoind test_bitcoin
32codesign -s - bitcoin-cli bitcoin-qt bitcoin-tx bitcoin-util bitcoin-wallet bitcoind test_bitcoin
33```
34
35Compatibility
36==============
37
38Bitcoin Core is supported and extensively tested on operating systems
39using the Linux Kernel 3.17+, macOS 11.0+, and Windows 7 and newer. Bitcoin
40Core should also work on most other UNIX-like systems but is not as
41frequently tested on them. It is not recommended to use Bitcoin Core on
42unsupported systems.
43
44Notable changes
45===============
46
47Testnet4/BIP94 support
48-----
49
50Support for Testnet4 as specified in [BIP94](https://github.com/bitcoin/bips/blob/master/bip-0094.mediawiki)
51has been added. The network can be selected with the `-testnet4` option and
52the section header is also named `[testnet4]`.
53
54While the intention is to phase out support for Testnet3 in an upcoming
55version, support for it is still available via the known options in this
56release. (#29775)
57
58Windows Data Directory
59----------------------
60
61The default data directory on Windows has been moved from `C:\Users\Username\AppData\Roaming\Bitcoin`
62to `C:\Users\Username\AppData\Local\Bitcoin`. Bitcoin Core will check the existence
63of the old directory first and continue to use that directory for backwards
64compatibility if it is present. (#27064)
65
66JSON-RPC 2.0 Support
67--------------------
68
69The JSON-RPC server now recognizes JSON-RPC 2.0 requests and responds with
70strict adherence to the [specification](https://www.jsonrpc.org/specification).
71See [JSON-RPC-interface.md](https://github.com/bitcoin/bitcoin/blob/master/doc/JSON-RPC-interface.md#json-rpc-11-vs-20) for details. (#27101)
72
73JSON-RPC clients may need to be updated to be compatible with the JSON-RPC server.
74Please open an issue on GitHub if any compatibility issues are found.
75
76libbitcoinconsensus Removal
77---------------------------
78
79The libbitcoin-consensus library was deprecated in 27.0 and is now completely removed. (#29648)
80
81P2P and Network Changes
82-----------------------
83
84- Previously if Bitcoin Core was listening for P2P connections, either using
85  default settings or via `bind=addr:port` it would always also bind to
86  `127.0.0.1:8334` to listen for Tor connections. It was not possible to switch
87  this off, even if the node didn't use Tor. This has been changed and now
88  `bind=addr:port` results in binding on `addr:port` only. The default behavior
89  of binding to `0.0.0.0:8333` and `127.0.0.1:8334` has not been changed.
90
91  If you are using a `bind=...` configuration without `bind=...=onion` and rely
92  on the previous implied behavior to accept incoming Tor connections at
93  `127.0.0.1:8334`, you need to now make this explicit by using
94  `bind=... bind=127.0.0.1:8334=onion`. (#22729)
95
96- Bitcoin Core will now fail to start up if any of its P2P binds fail, rather
97  than the previous behaviour where it would only abort startup if all P2P
98  binds had failed. (#22729)
99
100- UNIX domain sockets can now be used for proxy connections. Set `-onion` or `-proxy`
101  to the local socket path with the prefix `unix:` (e.g. `-onion=unix:/home/me/torsocket`).
102  (#27375)
103
104- UNIX socket paths are now accepted for `-zmqpubrawblock` and `-zmqpubrawtx` with
105  the format `-zmqpubrawtx=unix:/path/to/file` (#27679)
106
107- Additional "in" and "out" flags have been added to `-whitelist` to control whether
108  permissions apply to inbound connections and/or manual ones (default: inbound only). (#27114)
109
110- Transactions having a feerate that is too low will be opportunistically paired with
111  their child transactions and submitted as a package, thus enabling the node to download
112  1-parent-1-child packages using the existing transaction relay protocol. Combined with
113  other mempool policies, this change allows limited "package relay" when a parent transaction
114  is below the mempool minimum feerate. Topologically Restricted Until Confirmation (TRUC)
115  parents are additionally allowed to be below the minimum relay feerate (i.e., pay 0 fees).
116  Use the `submitpackage` RPC to submit packages directly to the node. Warning: this P2P
117  feature is limited (unlike the `submitpackage` interface, a child with multiple unconfirmed
118  parents is not supported) and not yet reliable under adversarial conditions. (#28970)
119
120Mempool Policy Changes
121----------------------
122
123- Transactions with version number set to 3 are now treated as standard on all networks (#29496),
124  subject to opt-in Topologically Restricted Until Confirmation (TRUC) transaction policy as
125  described in [BIP 431](https://github.com/bitcoin/bips/blob/master/bip-0431.mediawiki).  The
126  policy includes limits on spending unconfirmed outputs (#28948), eviction of a previous descendant
127  if a more incentive-compatible one is submitted (#29306), and a maximum transaction size of 10,000vB
128  (#29873). These restrictions simplify the assessment of incentive compatibility of accepting or
129  replacing TRUC transactions, thus ensuring any replacements are more profitable for the node and
130  making fee-bumping more reliable.
131
132- Pay To Anchor (P2A) is a new standard witness output type for spending,
133  a newly recognised output template. This allows for key-less anchor
134  outputs, with compact spending conditions for additional efficiencies on
135  top of an equivalent `sh(OP_TRUE)` output, in addition to the txid stability
136  of the spending transaction.
137  N.B. propagation of this output spending on the network will be limited
138  until a sufficient number of nodes on the network adopt this upgrade. (#30352)
139
140- Limited package RBF is now enabled, where the proposed conflicting package would result in
141  a connected component, aka cluster, of size 2 in the mempool. All clusters being conflicted
142  against must be of size 2 or lower. (#28984)
143
144- The default value of the `-mempoolfullrbf` configuration option has been changed from 0 to 1,
145  i.e. `mempoolfullrbf=1`. (#30493)
146
147Updated RPCs
148------------
149
150- The `dumptxoutset` RPC now returns the UTXO set dump in a new and
151  improved format. Correspondingly, the `loadtxoutset` RPC now expects
152  this new format in the dumps it tries to load. Dumps with the old
153  format are no longer supported and need to be recreated using the
154  new format to be usable. (#29612)
155
156- AssumeUTXO mainnet parameters have been added for height 840,000.
157  This means the `loadtxoutset` RPC can now be used on mainnet with
158  the matching UTXO set from that height. (#28553)
159
160- The `warnings` field in `getblockchaininfo`, `getmininginfo` and
161  `getnetworkinfo` now returns all the active node warnings as an array
162  of strings, instead of a single warning. The current behaviour
163  can be temporarily restored by running Bitcoin Core with the configuration
164  option `-deprecatedrpc=warnings`. (#29845)
165
166- Previously when using the `sendrawtransaction` RPC and specifying outputs
167  that are already in the UTXO set, an RPC error code of `-27` with the
168  message "Transaction already in block chain" was returned in response.
169  The error message has been changed to "Transaction outputs already in utxo set"
170  to more accurately describe the source of the issue. (#30212)
171
172- The default mode for the `estimatesmartfee` RPC has been updated from `conservative` to `economical`,
173  which is expected to reduce over-estimation for many users, particularly if Replace-by-Fee is an option.
174  For users that require high confidence in their fee estimates at the cost of potentially over-estimating,
175  the `conservative` mode remains available. (#30275)
176
177- RPC `scantxoutset` now returns 2 new fields in the "unspents" JSON array: `blockhash` and `confirmations`.
178  See the scantxoutset help for details. (#30515)
179
180- RPC `submitpackage` now allows 2 new arguments to be passed: `maxfeerate` and `maxburnamount`. See the
181  subtmitpackage help for details. (#28950)
182
183Changes to wallet-related RPCs can be found in the Wallet section below.
184
185Updated REST APIs
186-----------------
187- Parameter validation for `/rest/getutxos` has been improved by rejecting
188  truncated or overly large txids and malformed outpoint indices via raising
189  an HTTP_BAD_REQUEST "Parse error". These requests were previously handled
190  silently. (#30482, #30444)
191
192Build System
193------------
194
195- GCC 11.1 or later, or Clang 16.0 or later,
196are now required to compile Bitcoin Core. (#29091, #30263)
197
198- The minimum required glibc to run Bitcoin Core is now
1992.31. This means that RHEL 8 and Ubuntu 18.04 (Bionic)
200are no-longer supported. (#29987)
201
202- `--enable-lcov-branch-coverage` has been removed, given
203incompatibilities between lcov version 1 & 2. `LCOV_OPTS`
204should be used to set any options instead. (#30192)
205
206Updated Settings
207----------------
208
209- When running with `-alertnotify`, an alert can now be raised multiple
210times instead of just once. Previously, it was only raised when unknown
211new consensus rules were activated. Its scope has now been increased to
212include all kernel warnings. Specifically, alerts will now also be raised
213when an invalid chain with a large amount of work has been detected.
214Additional warnings may be added in the future. (#30058)
215
216Changes to GUI or wallet related settings can be found in the GUI or Wallet section below.
217
218Wallet
219------
220
221- The wallet now detects when wallet transactions conflict with the mempool. Mempool-conflicting
222  transactions can be seen in the `"mempoolconflicts"` field of `gettransaction`. The inputs
223  of mempool-conflicted transactions can now be respent without manually abandoning the
224  transactions when the parent transaction is dropped from the mempool, which can cause wallet
225  balances to appear higher. (#27307)
226
227- A new `max_tx_weight` option has been added to the RPCs `fundrawtransaction`, `walletcreatefundedpsbt`, and `send`.
228It specifies the maximum transaction weight. If the limit is exceeded during funding, the transaction will not be built.
229The default value is 4,000,000 WU. (#29523)
230
231- A new `createwalletdescriptor` RPC allows users to add new automatically generated
232  descriptors to their wallet. This can be used to upgrade wallets created prior to the
233  introduction of a new standard descriptor, such as taproot. (#29130)
234
235- A new RPC `gethdkeys` lists all of the BIP32 HD keys in use by all of the descriptors in the wallet.
236  These keys can be used in conjunction with `createwalletdescriptor` to create and add single key
237  descriptors to the wallet for a particular key that the wallet already knows. (#29130)
238
239- The `sendall` RPC can now spend unconfirmed change and will include additional fees as necessary
240  for the resulting transaction to bump the unconfirmed transactions' feerates to the specified feerate. (#28979)
241
242- In RPC `bumpfee`, if a `fee_rate` is specified, the feerate is no longer restricted
243  to following the wallet's incremental feerate of 5 sat/vb. The feerate must still be
244  at least the sum of the original fee and the mempool's incremental feerate. (#27969)
245
246GUI Changes
247-----------
248
249- The "Migrate Wallet" menu allows users to migrate any legacy wallet in their wallet
250directory, regardless of the wallets loaded. (gui#824)

src/wallet/receive.cpp

src/wallet/coinselection.cpp

src/consensus/validation.h

src/primitives/transaction.cpp

src/script/descriptor.cpp

src/bitcoin-cli.cpp

src/rpc/blockchain.cpp

src/rpc/rawtransaction.cpp

src/init.cpp

src/crypto/sha256.cpp

src/consensus/merkle.h

src/consensus/tx_check.h

src/consensus/tx_verify.h

src/policy/feerate.h

src/policy/feerate.cpp

src/primitives/transaction_identifier.h

src/chainparamsbase.h

src/chainparamsbase.cpp

src/util/moneystr.cpp

src/crypto/ripemd160.h

src/crypto/sha1.h

src/crypto/sha512.h

src/crypto/hmac_sha256.h

src/crypto/hmac_sha512.h

src/crypto/hmac_sha256.cpp

src/crypto/hmac_sha512.cpp

src/crypto/hkdf_sha256_32.h

src/crypto/hkdf_sha256_32.cpp

src/support/cleanse.h

src/support/cleanse.cpp

src/crypto/siphash.cpp

src/crypto/muhash.h

src/crypto/chacha20.h

src/crypto/poly1305.h

src/crypto/chacha20poly1305.h

src/crypto/chacha20poly1305.cpp

src/util/chaintype.cpp

src/util/obfuscation.h

src/util/byte_units.h

src/util/overflow.h

src/blockencodings.cpp

src/net_permissions.cpp

src/policy/packages.cpp

src/policy/rbf.cpp

src/policy/truc_policy.cpp

src/policy/ephemeral_policy.cpp

src/policy/settings.cpp

src/policy/policy.cpp

src/node/transaction.cpp

src/node/coin.cpp

src/rpc/client.cpp

src/rpc/external_signer.cpp

src/rpc/request.cpp

src/rpc/server_util.cpp

src/rpc/fees.cpp

src/rpc/output_script.cpp

src/rpc/rawtransaction_util.cpp

src/rpc/rawtransaction_util.h

src/rpc/register.h

src/rpc/request.h

src/rpc/server_util.h

src/rpc/protocol.h

src/rpc/server.h

src/rpc/signmessage.cpp

src/rpc/txoutproof.cpp

src/rpc/util.cpp

src/rpc/util.h

src/wallet/rpc/addresses.cpp

src/wallet/rpc/backup.cpp

src/wallet/rpc/coins.cpp

src/wallet/rpc/encrypt.cpp

src/wallet/rpc/signmessage.cpp

src/wallet/rpc/util.cpp

src/wallet/rpc/util.h

src/wallet/coincontrol.cpp

src/wallet/coincontrol.h

src/wallet/context.cpp

src/wallet/context.h

src/wallet/crypter.cpp

src/wallet/crypter.h

src/wallet/db.cpp

src/wallet/export.cpp

src/wallet/external_signer_scriptpubkeyman.cpp

src/wallet/rpc/spend.cpp

src/wallet/rpc/transactions.cpp

src/wallet/rpc/wallet.cpp

src/wallet/feebumper.cpp

src/wallet/feebumper.h

src/index/base.h

src/index/base.cpp

src/index/txindex.h

src/index/txindex.cpp

src/index/txindex_key.h

src/index/txospenderindex.h

src/index/txospenderindex.cpp

src/index/blockfilterindex.h

src/index/blockfilterindex.cpp

src/index/coinstatsindex.h

src/index/coinstatsindex.cpp

src/index/db_key.h

src/index/disktxpos.h

src/kernel/chain.cpp

src/kernel/chain.h

src/kernel/checks.cpp

src/kernel/checks.h

src/kernel/context.cpp

src/kernel/context.h

src/kernel/cs_main.cpp

src/kernel/cs_main.h

src/kernel/disconnected_transactions.cpp

src/kernel/disconnected_transactions.h

src/kernel/mempool_removal_reason.cpp

src/kernel/mempool_removal_reason.h

src/kernel/coinstats.cpp

src/kernel/coinstats.h

src/kernel/chainparams.cpp

src/kernel/chainparams.h

src/wallet/sqlite.cpp

src/wallet/sqlite.h

src/wallet/transaction.cpp

src/wallet/transaction.h

src/wallet/dump.cpp

src/wallet/dump.h

src/wallet/init.cpp

src/wallet/walletutil.cpp

src/wallet/walletutil.h

src/wallet/wallettool.cpp

src/wallet/wallettool.h

src/wallet/export.h

src/wallet/migrate.cpp

src/wallet/migrate.h

src/wallet/db.h

src/wallet/walletdb.cpp

src/wallet/interfaces.cpp

src/wallet/scriptpubkeyman.cpp

src/wallet/scriptpubkeyman.h

src/kernel/bitcoinkernel.cpp

src/kernel/bitcoinkernel.h

src/kernel/bitcoinkernel_wrapper.h

src/node/chainstate.cpp

src/node/chainstate.h

src/node/blockstorage.cpp

src/node/blockstorage.h

src/node/mempool_persist.cpp

src/node/mempool_persist.h

src/node/utxo_snapshot.cpp

src/node/utxo_snapshot.h

src/node/kernel_notifications.cpp

src/node/kernel_notifications.h

src/node/blockmanager_args.cpp

src/kernel/blockmanager_opts.h

src/util/expected.cpp

src/policy/settings.h

src/util/types.h

src/kernel/messagestartchars.h

src/kernel/warning.h

src/util/exception.h

src/common/license_info.h

src/node/coins_view_args.h

src/node/database_args.h

src/util/batchpriority.h

src/util/ui_change_type.h

src/node/coins_view_args.cpp

src/node/peerman_args.h

src/util/serfloat.h

src/node/blockmanager_args.h

src/node/database_args.cpp

src/util/overloaded.h

src/interfaces/types.h

src/node/chainstatemanager_args.h

src/node/minisketchwrapper.h

src/util/macros.h

src/util/syserror.h

src/common/run_command.h

src/util/bytevectorhash.cpp

src/node/mempool_persist_args.cpp

src/util/exec.h

src/util/rbf.h

src/crypto/hex_base.h

src/node/mempool_persist_args.h

src/interfaces/echo.h

src/util/any.h

src/util/batchpriority.cpp

src/util/threadnames.h

src/node/coin.h

src/node/mempool_args.h

src/util/asmap.h

src/util/bytevectorhash.h

src/node/context.cpp

src/util/insert.h

src/util/readwritefile.h

src/node/peerman_args.cpp

src/node/interface_ui.cpp

src/interfaces/handler.h

src/node/mining_args.h

src/util/hasher.cpp

src/common/init.h

src/kernel/mempool_limits.h

src/common/system.h

src/crypto/sha3.h

src/util/threadinterrupt.cpp

src/node/protocol_version.h

src/util/exception.cpp

src/common/messages.h

src/node/connection_types.cpp

src/util/bip32.h

src/common/license_info.cpp

src/util/stdmutex.h

src/common/run_command.cpp

src/util/check.cpp

src/util/golombrice.h

src/node/types.h

src/node/timeoffsets.h

src/util/readwritefile.cpp

src/util/fastrange.h

src/util/signalinterrupt.h

src/util/task_runner.h

src/util/syserror.cpp

src/common/interfaces.cpp

src/common/types.h

src/util/threadinterrupt.h

src/kernel/chainstatemanager_opts.h

src/node/psbt.h

src/policy/ephemeral_policy.h

src/util/trace.h

src/common/url.cpp

src/kernel/mempool_options.h

src/util/serfloat.cpp

src/kernel/notifications_interface.h

src/node/timeoffsets.cpp

src/node/warnings.cpp

src/util/hash_type.h

src/crypto/hex_base.cpp

src/node/eviction.h

src/util/tokenbucket.h

src/crypto/aes.h

src/common/pcp.h

src/util/feefrac.cpp

src/node/transaction.h

src/util/threadnames.cpp

src/common/signmessage.h

src/util/exec.cpp

src/util/signalinterrupt.cpp

src/clientversion.cpp

src/common/signmessage.cpp

src/compat/assumptions.h

src/compat/byteswap.h

src/deploymentinfo.cpp

src/deploymentinfo.h

src/deploymentstatus.cpp

src/deploymentstatus.h

src/dummywallet.cpp

src/external_signer.h

src/init/bitcoin-gui.cpp

src/init/bitcoin-node.cpp

src/init/bitcoin-qt.cpp

src/init/bitcoin-wallet.cpp

src/init/bitcoind.cpp

src/init/common.h

src/interfaces/init.h

src/interfaces/ipc.h

src/key_io.h

src/logging/categories.h

src/logging/timer.h

src/mapport.h

src/musig.h

src/net_permissions.h

src/netgroup.h

src/netmessagemaker.h

src/node/chainstatemanager_args.cpp

src/node/connection_types.h

src/node/context.h

src/node/interface_ui.h

src/node/mempool_args.cpp

src/node/mining_args.cpp

src/node/minisketchwrapper.cpp

src/node/txreconciliation.h

src/policy/fees/estimator_args.cpp

src/policy/fees/estimator_args.h

src/policy/fees/estimator_man.cpp

src/policy/fees/estimator_man.h

src/policy/packages.h

src/policy/rbf.h

src/policy/truc_policy.h

src/pow.h

src/primitives/block.cpp

src/randomenv.h

src/rest.h

src/script/keyorigin.h

src/script/parsing.cpp

src/script/parsing.h

src/script/script_error.h

src/script/sigcache.cpp

src/script/sigcache.h

src/script/solver.h

src/script/verify_flags.h

src/semaphore_grant.h

src/signet.h

src/span.h

src/support/allocators/secure.h

src/support/allocators/zeroafterfree.h

src/util/tokenpipe.cpp

src/util/translation.h

src/util/vector.h

src/versionbits.h

src/versionbits_impl.h

src/wallet/external_signer_scriptpubkeyman.h

src/wallet/fees.h

src/wallet/load.h

src/wallet/receive.h

src/wallet/rpc/wallet.h

src/wallet/types.h

src/walletinitinterface.h

src/zmq/zmqabstractnotifier.cpp

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