Bitcoin Core 31.0

Bitcoin Core installation binaries can be downloaded from bitcoincore.org and the source-code is available from the Bitcoin Core source repository.

v31.0 Release Notes

Bitcoin Core version 31.0 is now available from:

https://bitcoincore.org/bin/bitcoin-core-31.0/

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 macOS) 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

Bitcoin Core is supported and tested on the following operating systems or newer: Linux Kernel 3.17, macOS 14, and Windows 10 (version 1903). 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.

Notable changes

The default -dbcache value has been increased to 1024 MiB from 450 MiB on systems where at least 4096 MiB of RAM is detected. This improves performance but increases memory usage. On some systems (for example when running in containers), the detected RAM may exceed the memory actually available, which can lead to out-of-memory conditions. To maintain the previous behavior, set -dbcache=450. See reduce-memory.md for further guidance on low-memory systems. (#34692)

Mempool

The mempool has been reimplemented with a new design (“cluster mempool”), to facilitate better decision-making when constructing block templates, evicting transactions, relaying transactions, and validating replacement transactions (RBF). Most changes should be transparent to users, but some behavior changes are noted:

  • The mempool no longer enforces ancestor or descendant size/count limits. Instead, two new default policy limits are introduced governing connected components, or clusters, in the mempool, limiting clusters to 64 transactions and up to 101 kB in virtual size. Transactions are considered to be in the same cluster if they are connected to each other via any combination of parent/child relationships in the mempool. These limits can be overridden using command-line arguments; see the extended help (-help-debug) for more information.

  • Within the mempool, transactions are ordered based on the feerate at which they are expected to be mined, which takes into account the full set, or “chunk”, of transactions that would be included together (e.g., a parent and its child, or more complicated subsets of transactions). This ordering is utilized by the algorithms that implement transaction selection for constructing block templates; eviction from the mempool when it is full; and transaction relay announcements to peers.

  • The replace-by-fee validation logic has been updated so that transaction replacements are only accepted if the resulting mempool’s feerate diagram is strictly better than before the replacement. This eliminates all known cases of replacements occurring that make the mempool worse off, which was possible under previous RBF rules. For singleton transactions (that are in clusters by themselves) it’s sufficient for a replacement to have a higher fee and feerate than the original. See delvingbitcoin.org post for more information.

  • Two new RPCs have been added: getmempoolcluster will provide the set of transactions in the same cluster as the given transaction, along with the ordering of those transactions and grouping into chunks; and getmempoolfeeratediagram will return the feerate diagram of the entire mempool.

  • Chunk size and chunk fees are now also included in the output of getmempoolentry.

  • The “CPFP Carveout” has been removed from the mempool logic. The CPFP carveout allowed one additional child transaction to be added to a package that’s already at its descendant limit, but only if that child has exactly one ancestor (the package’s root) and is small (no larger than 10kvB). Nothing is allowed to bypass the cluster count limit. It is expected that smart contracting use-cases requiring similar functionality employ TRUC transactions and sibling eviction instead going forward.

  • Some additional discussion can be found at doc/policy/mempool-terminology.md and doc/policy/mempool-replacements.md.

P2P and network changes

  • Normally local transactions are broadcast to all connected peers with which we do transaction relay. Now, for the sendrawtransaction RPC this behavior can be changed to only do the broadcast via the Tor or I2P networks. A new boolean option -privatebroadcast has been added to enable this behavior. This improves the privacy of the transaction originator in two aspects:
    1. Their IP address (and thus geolocation) is never known to the recipients.
    2. If the originator sends two otherwise unrelated transactions, they will not be linkable. This is because a separate connection is used for broadcasting each transaction. (#29415)

  • New RPCs have been added to introspect and control private broadcast: getprivatebroadcastinfo reports transactions currently being privately broadcast, and abortprivatebroadcast removes matching transactions from the private broadcast queue. (#34329)

  • Transactions participating in one-parent-one-child package relay can now have the parent with a feerate lower than the -minrelaytxfee feerate, even 0 fee. This expands the change from 28.0 to also cover packages of non-TRUC transactions. Note that in general the package child can have additional unconfirmed parents, but they must already be in-mempool for the new package to be relayed. (#33892)

  • The release has asmap data embedded for the first time, allowing the asmap feature to be used without any externally sourced file. The embedded map was created on 2026-03-05. Despite the data being available, the option remains off-by-default. Users still need to set -asmap or -asmap=1 explicitly to make it possible to use a peer’s ASN (ISP/hoster identifier) in netgroup bucketing in order to ensure a higher diversity in their peer set.

Updated RPCs

  • gettxspendingprevout has 2 new optional arguments: mempool_only and return_spending_tx. If mempool_only is true it will limit scans to the mempool even if txospenderindex is available. If return_spending_tx is true, the full spending tx will be returned. In addition if txospenderindex is available and a confirmed spending transaction is found, its block hash will be returned. (#24539)

  • The getpeerinfo RPC no longer returns the startingheight field unless the configuration option -deprecatedrpc=startingheight is used. The startingheight field will be fully removed in the next major release. (#34197)

  • The getblock RPC now returns a coinbase_tx object at verbosity levels 1, 2, and 3. It contains version, locktime, sequence, coinbase and witness. This allows for efficiently querying coinbase transaction properties without fetching the full transaction data at verbosity 2+. (#34512)

REST API

  • A new REST API endpoint (/rest/blockpart/<BLOCK-HASH>.<bin|hex>?offset=<OFFSET>&size=<SIZE>) has been introduced for efficiently fetching a range of bytes from block <BLOCK-HASH>. (#33657)

Build System

  • The minimum supported Clang compiler version has been raised to 17.0 (#33555).
  • The minimum supported GCC compiler version has been raised to 12.1 (#33842).

Updated settings

  • The -paytxfee startup option and the settxfee RPC are now deleted after being deprecated in Bitcoin Core 30.0. They used to allow the user to set a static fee rate for wallet transactions, which could potentially lead to overpaying or underpaying. Users should instead rely on fee estimation or specify a fee rate per transaction using the fee_rate argument in RPCs such as fundrawtransaction, sendtoaddress, send, sendall, and sendmany. (#32138)

  • Specifying -asmap or -asmap=1 will load the embedded asmap data instead of an external file. In previous releases, if -asmap was specified without a filename, this would try to load an ip_asn.map data file. Now loading an external asmap file always requires an explicit filename like -asmap=ip_asn.map.

  • The -maxorphantx startup option has been removed. It was previously deprecated and has no effect anymore since v30.0. (#33872)

  • tor has been removed as a network specification. It was deprecated in favour of onion in v0.17.0. (#34031)

  • When -logsourcelocations is enabled, the log output now contains just the function name instead of the entire function signature. (#34088)

  • The default -dbcache value has been increased to 1024 MiB from 450 MiB on systems where at least 4096 MiB of RAM is detected. This is a performance increase, but will use more memory. To maintain the previous behaviour, set -dbcache=450. (#34692)

  • -privatebroadcast is added to enable private broadcast behavior for sendrawtransaction.

New settings

  • -txospenderindex enables the creation of a transaction output spender index that, if present, will be scanned by gettxspendingprevout if a spending transaction was not found in the mempool. (#24539)

GUI changes

  • The GUI has been updated to Qt 6.8. (#34650)

  • The createwallet, createwalletdescriptor and migratewallet commands are filtered from the console history to improve security and privacy. (gui#901)

  • The Restore Wallet dialog shows an error message if the restored wallet name is empty. (gui#924)

Fee Estimation

The Bitcoin Core fee estimator minimum fee rate bucket was updated from 1 sat/vB to 0.1 sat/vB, which matches the node’s default minrelaytxfee. This means that for a given confirmation target, if a sub-1 sat/vB fee rate bucket is the minimum tracked with sufficient data, its average value will be returned as the fee rate estimate.

Restarting a node with this change invalidates previously saved estimates in fee_estimates.dat, the fee estimator will start tracking fresh stats.

IPC Interface

  • The IPC mining interface now requires mining clients to use the latest mining.capnp schema. Clients built against older schemas will fail when calling Init.makeMining and receive an RPC error indicating the old mining interface is no longer supported. Mining clients must update to the latest schema and regenerate bindings to continue working. (#34568)
  • Mining.createNewBlock now has a cooldown behavior (enabled by default) that waits for IBD to finish and for the tip to catch up. This usually prevents a flood of templates during startup, but is not guaranteed. (#34184)
  • Mining.interrupt() can be used to interrupt Mining.waitTipChanged and Mining.createNewBlock. (#34184)
  • Mining.createNewBlock and Mining.checkBlock now require a context parameter.
  • Mining.waitTipChanged now has a default timeout (effectively infinite / maxDouble) if the client omits it.
  • BlockTemplate.getCoinbaseTx() now returns a structured CoinbaseTx instead of raw bytes.
  • Removed BlockTemplate.getCoinbaseCommitment() and BlockTemplate.getWitnessCommitmentIndex().
  • Cap’n Proto default values were updated to match the corresponding C++ defaults for mining-related option structs (e.g. BlockCreateOptions, BlockWaitOptions, BlockCheckOptions).

Credits

Thanks to everyone who directly contributed to this release:

  • 0xb10c
  • Alexander Wiederin
  • Alfonso Roman Zubeldia
  • amisha
  • ANAVHEOBA
  • Andrew Toth
  • Anthony Towns
  • Antoine Poinsot
  • ANtutov
  • Anurag chavan
  • Ava Chow
  • bensig
  • Ben Westgate
  • billymcbip
  • b-l-u-e
  • Brandon Odiwuor
  • brunoerg
  • Bruno Garcia
  • Calin Culianu
  • Carl Dong
  • Chandra Pratap
  • Chris Stewart
  • Coder
  • Cory Fields
  • da1sychain
  • Daniela Brozzoni
  • Daniel Pfeifer
  • David Gumberg
  • dergoegge
  • Dmitry Goncharov
  • Enoch Azariah
  • Eugene Siegel
  • Fabian Jahr
  • fanquake
  • Fibonacci747
  • flack
  • frankomosh
  • furszy
  • glozow
  • Greg Sanders
  • Hao Xu
  • Hennadii Stepanov
  • Henry Romp
  • Hodlinator
  • ismaelsadeeq
  • janb84
  • jayvaliya
  • joaonevess
  • John Moffett
  • Josh Doman
  • kevkevinpal
  • l0rinc
  • Luke Dashjr
  • Mara van der Laan
  • MarcoFalke
  • marcofleon
  • Martin Zumsande
  • Matthew Zipkin
  • Max Edwards
  • Murch
  • Musa Haruna
  • naiyoma
  • nervana21
  • Novo
  • optout
  • pablomartin4btc
  • Padraic Slattery
  • Pieter Wuille
  • Pol Espinasa
  • pythcoiner
  • rkrux
  • Robin David
  • Roman Zeyde
  • rustaceanrob
  • Ryan Ofsky
  • SatsAndSports
  • scgbckbone
  • Sebastian Falbesoner
  • sedited
  • seduless
  • Sergi Delgado Segura
  • Sjors Provoost
  • SomberNight
  • sstone
  • stickies-v
  • stratospher
  • stringintech
  • Suhas Daftuar
  • tboy1337
  • TheCharlatan
  • Tim Ruffing
  • Vasil Dimov
  • w0xlt
  • WakeTrainDev
  • Weixie Cui
  • willcl-ark
  • Woolfgm
  • yancy
  • Yash Bhutwala
  • yuvicc
  • zaidmstrr

As well as to everyone that helped with translations on Transifex.

Bitcoin Core 31.0 was published on .