diff --git a/doc/release-notes/release-notes-31.0.md b/doc/release-notes/release-notes-31.0.md new file mode 100644 index 00000000000..d5dd0f243c2 --- /dev/null +++ b/doc/release-notes/release-notes-31.0.md @@ -0,0 +1,372 @@ +v31.0 Release Notes +=================== + +Bitcoin Core version 31.0 is now available from: + + + +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: + + + +To receive security and update notifications, please subscribe to: + + + +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](https://github.com/bitcoin/bitcoin/blob/master/doc/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](https://delvingbitcoin.org/t/an-overview-of-the-cluster-mempool-proposal/393#rbf-can-now-be-made-incentive-compatible-for-miners-11) +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](https://github.com/bitcoin/bitcoin/blob/master/doc/policy/mempool-terminology.md) +and +[doc/policy/mempool-replacements.md](https://github.com/bitcoin/bitcoin/blob/master/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](https://github.com/bitcoin/bitcoin/pull/34696). 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/.?offset=&size=`) has been +introduced for efficiently fetching a range of bytes from block ``. +(#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](https://explore.transifex.com/bitcoin/bitcoin/).