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v30.0 Release Notes Draft

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Ryan Ofsky edited this page Sep 12, 2025 · 18 revisions

v30.0 Release Notes Draft

Bitcoin Core version v30.0 is now available from:

https://bitcoincore.org/bin/bitcoin-core-30.0/

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 operating systems using the Linux Kernel 3.17+, macOS 13+, and Windows 10+. 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

Policy

  • The maximum number of potentially executed legacy signature operations in a single standard transaction is now limited to 2500. Signature operations in all previous output scripts, in all input scripts, as well as all P2SH redeem scripts (if there are any) are counted toward the limit. The new limit is assumed to not affect any known typically formed standard transactions. The change was done to prepare for a possible BIP54 deployment in the future. (#32521)

  • -datacarriersize is increased to 100,000 by default, which effectively uncaps the limit (as the maximum transaction size limit will be hit first). It can be overridden with -datacarriersize=83 to revert to the limit enforced in previous versions. Both -datacarrier and -datacarriersize options have been marked as deprecated and are expected to be removed in a future release. (#32406)

  • Multiple data carrier (OP_RETURN) outputs in a transaction are now permitted for relay and mining. The -datacarriersize limit applies to the aggregate size of the scriptPubKeys across all such outputs in a transaction, not including the scriptPubKey size itself. (#32406)

  • The minimum block feerate (-blockmintxfee) has been changed to 0.001 satoshi per vB. It can still be changed using the configuration option. (#33106)

  • The default minimum relay feerate (-minrelaytxfee) and incremental relay feerate (-incrementalrelayfee) have been changed to 0.1 satoshis per vB. They can still be changed using their respective configuration options, but it is recommended to change both together if you decide to do so. (#33106)

Other minimum feerates (e.g. the dust feerate, the minimum returned by the fee estimator, and all feerates used by the wallet) remain unchanged. The mempool minimum feerate still changes in response to high volume.

Note that unless these lower defaults are widely adopted across the network, transactions created with lower fee rates are not guaranteed to propagate or confirm. The wallet feerates remain unchanged; -mintxfee must be changed before attempting to create transactions with lower feerates using the wallet. (#33106)

P2P and network changes

  • Opportunistic 1-parent-1-child package relay has been improved to handle situations when the child already has unconfirmed parent(s) in the mempool. This means that 1p1c packages can be accepted and propagate, even if they are connected to broader topologies: multi-parent-1-child (where only 1 parent requires fee-bumping), grandparent-parent-child (where only parent requires fee-bumping) etc. (#31385)

  • The transaction orphanage, which holds transactions with missing inputs temporarily while the node attempts to fetch its parents, now has improved Denial of Service protections. Previously, it enforced a maximum number of unique transactions (default 100, configurable using -maxorphantx). Now, its limits are as follows: the number of entries (unique by wtxid and peer), plus each unique transaction's input count divided by 10, must not exceed 3,000. The total weight of unique transactions must not exceed 404,000 Wu multiplied by the number of peers. (#31829)

  • The -maxorphantx option no longer has any effect, since the orphanage no longer limits the number of unique transactions. Users should remove this configuration option if they were using it, as the setting will cause an error in future versions when it is no longer recognized. (#31829)

New bitcoin command

A new bitcoin command line tool has been added to make features more discoverable and convenient to use. The bitcoin tool just calls other executables and does not implement any functionality on its own. Specifically bitcoin node is a synonym for bitcoind, bitcoin gui is a synonym for bitcoin-qt, and bitcoin rpc is a synonym for bitcoin-cli -named. Other commands and options can be listed with bitcoin help. The new bitcoin command is an alternative to calling other commands directly, but it doesn't replace them, and there are no plans to deprecate existing commands. (#31375)

IPC Mining Interface

The new bitcoin command does support one new feature: an (experimental) IPC Mining Interface that allows the node to work with Stratum v2 or other mining client software, see #31098. When the node is started with bitcoin -m node -ipcbind=unix it will listen on a unix socket for IPC client connections, allowing clients to request block templates and submit mined blocks. The -m option launches a new internal binary (bitcoin-node instead of bitcoind) and is currently required but will become optional in the future (with #33229).

IPC connectivity introduces new dependencies (see multiprocess.md), which can be turned off with the -DENABLE_IPC=OFF build option if you do not intend to use IPC. (#31802)

Install changes

The test_bitcoin executable is now installed in libexec/ instead of bin/. It can still be executed directly, or accessed through the new bitcoin command as bitcoin test. The libexec/ directory also contains new bitcoin-node and bitcoin-gui binaries which support IPC features and are called through the bitcoin tool. In source builds only, test_bitcoin-qt, bench_bitcoin, and bitcoin-chainstate are also now installed to libexec/ instead of bin/ and can be accessed through the new bitcoin command. See bitcoin help output for details. (#31679)

Indexes

  • The implementation of coinstatsindex was changed to prevent an overflow bug that could already be observed on the default Signet. The new version of the index will need to be synced from scratch when starting the upgraded node for the first time. The new version is stored in /indexes/coinstatsindex/ in contrast to the old version which was stored at /indexes/coinstats/. The old version of the index is not deleted by the upgraded node in case the user chooses to downgrade their node in the future. If the user does not plan to downgrade it is safe for them to remove /indexes/coinstats/ from their datadir. A future release of Bitcoin Core may remove the old version of the index automatically. (#30469)

Logging

  • Unconditional logging to disk is now rate limited by giving each source location a quota of 1MiB per hour. Unconditional logging is any logging with a log level higher than debug, that is info, warning, and error. All logs will be prefixed with [*] if there is at least one source location that is currently being suppressed. (#32604)

  • When -logsourcelocations is enabled, the log output now contains the entire function signature instead of just the function name. (#32604)

Updated RPCs

  • The -paytxfee startup option and the settxfee RPC are now deprecated and will be removed in Bitcoin Core 31.0. They allowed 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. (#31278)

  • Any RPC in which one of the parameters are descriptors will throw an error if the provided descriptor contains a whitespace at the beginning or the end of the public key within a fragment - e.g. pk( KEY) or pk(KEY ). (#31603)

  • The submitpackage RPC, which allows submissions of child-with-parents packages, no longer requires that all unconfirmed parents be present. The package may contain other in-mempool ancestors as well. (#31385)

  • The waitfornewblock now takes an optional current_tip argument. It is also no longer hidden. (#30635)

  • The waitforblock and waitforblockheight RPCs are no longer hidden. (#30635)

  • The RPCs psbtbumpfee and bumpfee allow a replacement under fullrbf and no longer require BIP-125 signalling. (#31953)

  • Transaction Script validation errors used to return the reason for the error prefixed by either "mandatory-script-verify-flag-failed" if it was a consensus error, or "non-mandatory-script-verify-flag" (without "-failed") if it was a standardness error. This has been changed to "block-script-verify-flag-failed" and "mempool-script-verify-flag-failed" for all block and mempool errors respectively. (#33183)

Changes to wallet related RPCs can be found in the Wallet section below.

New RPCs

  • A new REST API endpoint (/rest/spenttxouts/BLOCKHASH) has been introduced for efficiently fetching spent transaction outputs using the block's undo data (#32540).

Build System

Updated settings

  • The -maxmempool and -dbcache startup parameters are now capped on 32-bit systems to 500MB and 1GiB respectively. (#32530)

  • The -natpmp option is now set to 1 by default. This means nodes with -listen enabled (the default) but running behind a firewall, such as a local network router, will be reachable if the firewall/router supports any of the PCP or NAT-PMP protocols. (#33004)

  • The -upnp setting has now been fully removed. Use -natpmp instead. (#32500)

  • Previously, -proxy specified the proxy for all networks (except I2P which uses -i2psam) and only the Tor proxy could have been specified separately via -onion. Now, the syntax of -proxy has been extended and it is possible to specify separately the proxy for IPv4, IPv6, Tor and CJDNS by appending = followed by the network name, for example -proxy=127.0.0.1:5555=ipv6 configures a proxy only for IPv6. The -proxy option can be used multiple times to define different proxies for different networks, such as -proxy=127.0.0.1:4444=ipv4 -proxy=10.0.0.1:6666=ipv6. Later settings override earlier ones for the same network; this can be used to remove an earlier all-networks proxy and use direct connections only for a given network, for example -proxy=127.0.0.1:5555 -proxy=0=cjdns. (#32425)

Changes to GUI or wallet related settings can be found in the GUI or Wallet section below.

New settings

Tools and Utilities

Wallet

  • BDB legacy wallets can no longer be created or loaded. They can be migrated to the new descriptor wallet format. Refer to the migratewallet RPC for more details.

  • The legacy wallet removal drops redundant options in the bitcoin-wallet tool, such as -withinternalbdb, -legacy, and -descriptors. Moreover, the legacy-only RPCs addmultisigaddress, dumpprivkey, dumpwallet, importaddress, importmulti, importprivkey, importpubkey, importwallet, newkeypool, sethdseed, and upgradewallet, are removed. (#32944, #28710, #32438, #31250)

  • Support has been added for spending TRUC transactions received by the wallet, as well as creating TRUC transactions. The wallet ensures that TRUC policy rules are being met. The wallet will throw an error if the user is trying to spend TRUC utxos with utxos of other versions. Additionally, the wallet will treat unconfirmed TRUC sibling transactions as mempool conflicts. The wallet will also ensure that transactions spending TRUC utxos meet the required size restrictions.(#32896)

  • Since descriptor wallets do not allow mixing watchonly and non-watchonly descriptors, the include_watchonly option (and its variants in naming) are removed from all RPCs that had it. (#32618)

  • The iswatchonly field is removed from any RPCs that returned it. (#32618)

  • unloadwallet - Return RPC_INVALID_PARAMETER when both the RPC wallet endpoint and wallet_name parameters are unspecified. Previously the RPC failed with a JSON parsing error. (#32845)

  • getdescriptoractivity - Mark blockhashes and scanobjects arguments as required, so the user receives a clear help message when either is missing. As in unloadwallet, previously the RPC failed with a JSON parsing error. (#32845)

The following RPCs now contain a version parameter that allows the user to create transactions of any standard version number (1-3):

  • createrawtransaction
  • createpsbt
  • send
  • sendall
  • walletcreatefundedpsbt (#32896)

GUI changes

  • A transaction's fee bump is allowed under fullrbf and no longer requires BIP-125 signalling. (#31953)

  • Custom column widths in the Transactions tab are reset as a side-effect of legacy wallet removal. (#32459)

Low-level changes

  • Logs now include which peer sent us a header. Additionally there are fewer redundant header log messages. A side-effect of this change is that for some untypical cases new headers aren't logged anymore, e.g. a direct BLOCK message with a previously unknown header and submitheader RPC. (#27826)

RPC

Tests

v30.0 change log

Credits

Thanks to everyone who directly contributed to this release:

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

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