Bitcoin Core version 0.13.1 is now available from: This is a new minor version release, including activation parameters for the segwit softfork, various bugfixes 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: Compatibility ============== Microsoft ended support for Windows XP on [April 8th, 2014](https://www.microsoft.com/en-us/WindowsForBusiness/end-of-xp-support), an OS initially released in 2001. This means that not even critical security updates will be released anymore. Without security updates, using a bitcoin wallet on a XP machine is irresponsible at least. In addition to that, with 0.12.x there have been varied reports of Bitcoin Core randomly crashing on Windows XP. It is [not clear](https://github.com/bitcoin/bitcoin/issues/7681#issuecomment-217439891) what the source of these crashes is, but it is likely that upstream libraries such as Qt are no longer being tested on XP. We do not have time nor resources to provide support for an OS that is end-of-life. From 0.13.0 on, Windows XP is no longer supported. Users are suggested to upgrade to a newer version of Windows, or install an alternative OS that is supported. No attempt is made to prevent installing or running the software on Windows XP, you can still do so at your own risk, but do not expect it to work: do not report issues about Windows XP to the issue tracker. From 0.13.1 onwards OS X 10.7 is no longer supported. 0.13.0 was intended to work on 10.7+, but severe issues with the libc++ version on 10.7.x keep it from running reliably. 0.13.1 now requires 10.8+, and will communicate that to 10.7 users, rather than crashing unexpectedly. Notable changes =============== Segregated witness soft fork ---------------------------- Segregated witness (segwit) is a soft fork that, if activated, will allow transaction-producing software to separate (segregate) transaction signatures (witnesses) from the part of the data in a transaction that is covered by the txid. This provides several immediate benefits: - **Elimination of unwanted transaction malleability:** Segregating the witness allows both existing and upgraded software to calculate the transaction identifier (txid) of transactions without referencing the witness, which can sometimes be changed by third-parties (such as miners) or by co-signers in a multisig spend. This solves all known cases of unwanted transaction malleability, which is a problem that makes programming Bitcoin wallet software more difficult and which seriously complicates the design of smart contracts for Bitcoin. - **Capacity increase:** Segwit transactions contain new fields that are not part of the data currently used to calculate the size of a block, which allows a block containing segwit transactions to hold more data than allowed by the current maximum block size. Estimates based on the transactions currently found in blocks indicate that if all wallets switch to using segwit, the network will be able to support about 70% more transactions. The network will also be able to support more of the advanced-style payments (such as multisig) than it can support now because of the different weighting given to different parts of a transaction after segwit activates (see the following section for details). - **Weighting data based on how it affects node performance:** Some parts of each Bitcoin block need to be stored by nodes in order to validate future blocks; other parts of a block can be immediately forgotten (pruned) or used only for helping other nodes sync their copy of the block chain. One large part of the immediately prunable data are transaction signatures (witnesses), and segwit makes it possible to give a different "weight" to segregated witnesses to correspond with the lower demands they place on node resources. Specifically, each byte of a segregated witness is given a weight of 1, each other byte in a block is given a weight of 4, and the maximum allowed weight of a block is 4 million. Weighting the data this way better aligns the most profitable strategy for creating blocks with the long-term costs of block validation. - **Signature covers value:** A simple improvement in the way signatures are generated in segwit simplifies the design of secure signature generators (such as hardware wallets), reduces the amount of data the signature generator needs to download, and allows the signature generator to operate more quickly. This is made possible by having the generator sign the amount of bitcoins they think they are spending, and by having full nodes refuse to accept those signatures unless the amount of bitcoins being spent is exactly the same as was signed. For non-segwit transactions, wallets instead had to download the complete previous transactions being spent for every payment they made, which could be a slow operation on hardware wallets and in other situations where bandwidth or computation speed was constrained. - **Linear scaling of sighash operations:** In 2015 a block was produced that required about 25 seconds to validate on modern hardware because of the way transaction signature hashes are performed. Other similar blocks, or blocks that could take even longer to validate, can still be produced today. The problem that caused this can't be fixed in a soft fork without unwanted side-effects, but transactions that opt-in to using segwit will now use a different signature method that doesn't suffer from this problem and doesn't have any unwanted side-effects. - **Increased security for multisig:** Bitcoin addresses (both P2PKH addresses that start with a '1' and P2SH addresses that start with a '3') use a hash function known as RIPEMD-160. For P2PKH addresses, this provides about 160 bits of security---which is beyond what cryptographers believe can be broken today. But because P2SH is more flexible, only about 80 bits of security is provided per address. Although 80 bits is very strong security, it is within the realm of possibility that it can be broken by a powerful adversary. Segwit allows advanced transactions to use the SHA256 hash function instead, which provides about 128 bits of security (that is 281 trillion times as much security as 80 bits and is equivalent to the maximum bits of security believed to be provided by Bitcoin's choice of parameters for its Elliptic Curve Digital Security Algorithm [ECDSA].) - **More efficient almost-full-node security** Satoshi Nakamoto's original Bitcoin paper describes a method for allowing newly-started full nodes to skip downloading and validating some data from historic blocks that are protected by large amounts of proof of work. Unfortunately, Nakamoto's method can't guarantee that a newly-started node using this method will produce an accurate copy of Bitcoin's current ledger (called the UTXO set), making the node vulnerable to falling out of consensus with other nodes. Although the problems with Nakamoto's method can't be fixed in a soft fork, Segwit accomplishes something similar to his original proposal: it makes it possible for a node to optionally skip downloading some blockchain data (specifically, the segregated witnesses) while still ensuring that the node can build an accurate copy of the UTXO set for the block chain with the most proof of work. Segwit enables this capability at the consensus layer, but note that Bitcoin Core does not provide an option to use this capability as of this 0.13.1 release. - **Script versioning:** Segwit makes it easy for future soft forks to allow Bitcoin users to individually opt-in to almost any change in the Bitcoin Script language when those users receive new transactions. Features currently being researched by Bitcoin Core contributors that may use this capability include support for Schnorr signatures, which can improve the privacy and efficiency of multisig transactions (or transactions with multiple inputs), and Merklized Abstract Syntax Trees (MAST), which can improve the privacy and efficiency of scripts with two or more conditions. Other Bitcoin community members are studying several other improvements that can be made using script versioning. Activation for the segwit soft fork is being managed using BIP9 versionbits. Segwit's version bit is bit 1, and nodes will begin tracking which blocks signal support for segwit at the beginning of the first retarget period after segwit's start date of 15 November 2016. If 95% of blocks within a 2,016-block retarget period (about two weeks) signal support for segwit, the soft fork will be locked in. After another 2,016 blocks, segwit will activate. For more information about segwit, please see the [segwit FAQ][], the [segwit wallet developers guide][] or BIPs [141][BIP141], [143][BIP143], [144][BIP144], and [145][BIP145]. If you're a miner or mining pool operator, please see the [versionbits FAQ][] for information about signaling support for a soft fork. [Segwit FAQ]: https://bitcoincore.org/en/2016/01/26/segwit-benefits/ [segwit wallet developers guide]: https://bitcoincore.org/en/segwit_wallet_dev/ [BIP141]: https://github.com/bitcoin/bips/blob/master/bip-0141.mediawiki [BIP143]: https://github.com/bitcoin/bips/blob/master/bip-0143.mediawiki [BIP144]: https://github.com/bitcoin/bips/blob/master/bip-0144.mediawiki [BIP145]: https://github.com/bitcoin/bips/blob/master/bip-0145.mediawiki [versionbits FAQ]: https://bitcoincore.org/en/2016/06/08/version-bits-miners-faq/ Null dummy soft fork ------------------- Combined with the segwit soft fork is an additional change that turns a long-existing network relay policy into a consensus rule. The `OP_CHECKMULTISIG` and `OP_CHECKMULTISIGVERIFY` opcodes consume an extra stack element ("dummy element") after signature validation. The dummy element is not inspected in any manner, and could be replaced by any value without invalidating the script. Because any value can be used for this dummy element, it's possible for a third-party to insert data into other people's transactions, changing the transaction's txid (called transaction malleability) and possibly causing other problems. Since Bitcoin Core 0.10.0, nodes have defaulted to only relaying and mining transactions whose dummy element was a null value (0x00, also called OP_0). The null dummy soft fork turns this relay rule into a consensus rule both for non-segwit transactions and segwit transactions, so that this method of mutating transactions is permanently eliminated from the network. Signaling for the null dummy soft fork is done by signaling support for segwit, and the null dummy soft fork will activate at the same time as segwit. For more information, please see [BIP147][]. [BIP147]: https://github.com/bitcoin/bips/blob/master/bip-0147.mediawiki Low-level RPC changes --------------------- - `importprunedfunds` only accepts two required arguments. Some versions accept an optional third arg, which was always ignored. Make sure to never pass more than two arguments. Linux ARM builds ---------------- With the 0.13.0 release, pre-built Linux ARM binaries were added to the set of uploaded executables. Additional detail on the ARM architecture targeted by each is provided below. The following extra files can be found in the download directory or torrent: - `bitcoin-${VERSION}-arm-linux-gnueabihf.tar.gz`: Linux binaries targeting the 32-bit ARMv7-A architecture. - `bitcoin-${VERSION}-aarch64-linux-gnu.tar.gz`: Linux binaries targeting the 64-bit ARMv8-A architecture. ARM builds are still experimental. If you have problems on a certain device or Linux distribution combination please report them on the bug tracker, it may be possible to resolve them. Note that the device you use must be (backward) compatible with the architecture targeted by the binary that you use. For example, a Raspberry Pi 2 Model B or Raspberry Pi 3 Model B (in its 32-bit execution state) device, can run the 32-bit ARMv7-A targeted binary. However, no model of Raspberry Pi 1 device can run either binary because they are all ARMv6 architecture devices that are not compatible with ARMv7-A or ARMv8-A. Note that Android is not considered ARM Linux in this context. The executables are not expected to work out of the box on Android. 0.13.1 Change log ================= Detailed release notes follow. This overview includes changes that affect behavior, not code moves, refactors and string updates. For convenience in locating the code changes and accompanying discussion, both the pull request and git merge commit are mentioned. ### Consensus - #8636 `9dfa0c8` Implement NULLDUMMY softfork (BIP147) (jl2012) - #8848 `7a34a46` Add NULLDUMMY verify flag in bitcoinconsensus.h (jl2012) - #8937 `8b66659` Define start and end time for segwit deployment (sipa) ### RPC and other APIs - #8581 `526d2b0` Drop misleading option in importprunedfunds (MarcoFalke) - #8699 `a5ec248` Remove createwitnessaddress RPC command (jl2012) - #8780 `794b007` Deprecate getinfo (MarcoFalke) - #8832 `83ad563` Throw JSONRPCError when utxo set can not be read (MarcoFalke) - #8884 `b987348` getblockchaininfo help: pruneheight is the lowest, not highest, block (luke-jr) - #8858 `3f508ed` rpc: Generate auth cookie in hex instead of base64 (laanwj) - #8951 `7c2bf4b` RPC/Mining: getblocktemplate: Update and fix formatting of help (luke-jr) ### Block and transaction handling - #8611 `a9429ca` Reduce default number of blocks to check at startup (sipa) - #8634 `3e80ab7` Add policy: null signature for failed CHECK(MULTI)SIG (jl2012) - #8525 `1672225` Do not store witness txn in rejection cache (sipa) - #8499 `9777fe1` Add several policy limits and disable uncompressed keys for segwit scripts (jl2012) - #8526 `0027672` Make non-minimal OP_IF/NOTIF argument non-standard for P2WSH (jl2012) - #8524 `b8c79a0` Precompute sighashes (sipa) - #8651 `b8c79a0` Predeclare PrecomputedTransactionData as struct (sipa) ### P2P protocol and network code - #8740 `42ea51a` No longer send local address in addrMe (laanwj) - #8427 `69d1cd2` Ignore `notfound` P2P messages (laanwj) - #8573 `4f84082` Set jonasschnellis dns-seeder filter flag (jonasschnelli) - #8712 `23feab1` Remove maxuploadtargets recommended minimum (jonasschnelli) - #8862 `7ae6242` Fix a few cases where messages were sent after requested disconnect (theuni) - #8393 `fe1975a` Support for compact blocks together with segwit (sipa) - #8282 `2611ad7` Feeler connections to increase online addrs in the tried table (EthanHeilman) - #8612 `2215c22` Check for compatibility with download in FindNextBlocksToDownload (sipa) - #8606 `bbf379b` Fix some locks (sipa) - #8594 `ab295bb` Do not add random inbound peers to addrman (gmaxwell) - #8940 `5b4192b` Add x9 service bit support to dnsseed.bluematt.me, seed.bitcoinstats.com (TheBlueMatt, cdecker) - #8944 `685e4c7` Remove bogus assert on number of oubound connections. (TheBlueMatt) - #8949 `0dbc48a` Be more agressive in getting connections to peers with relevant services (gmaxwell) ### Build system - #8293 `fa5b249` Allow building libbitcoinconsensus without any univalue (luke-jr) - #8492 `8b0bdd3` Allow building bench_bitcoin by itself (luke-jr) - #8563 `147003c` Add configure check for -latomic (ajtowns) - #8626 `ea51b0f` Berkeley DB v6 compatibility fix (netsafe) - #8520 `75f2065` Remove check for `openssl/ec.h` (laanwj) ### GUI - #8481 `d9f0d4e` Fix minimize and close bugs (adlawren) - #8487 `a37cec5` Persist the datadir after option reset (achow101) - #8697 `41fd852` Fix op order to append first alert (rodasmith) - #8678 `8e03382` Fix UI bug that could result in paying unexpected fee (jonasschnelli) - #8911 `7634d8e` Translate all files, even if wallet disabled (laanwj) - #8540 `1db3352` Fix random segfault when closing "Choose data directory" dialog (laanwj) - #7579 `f1c0d78` Show network/chain errors in the GUI (jonasschnelli) ### Wallet - #8443 `464dedd` Trivial cleanup of HD wallet changes (jonasschnelli) - #8539 `cb07f19` CDB: fix debug output (crowning-) - #8664 `091cdeb` Fix segwit-related wallet bug (sdaftuar) - #8693 `c6a6291` Add witness address to address book (instagibbs) - #8765 `6288659` Remove "unused" ThreadFlushWalletDB from removeprunedfunds (jonasschnelli) ### Tests and QA - #8713 `ae8c7df` create_cache: Delete temp dir when done (MarcoFalke) - #8716 `e34374e` Check legacy wallet as well (MarcoFalke) - #8750 `d6ebe13` Refactor RPCTestHandler to prevent TimeoutExpired (MarcoFalke) - #8652 `63462c2` remove root test directory for RPC tests (yurizhykin) - #8724 `da94272` walletbackup: Sync blocks inside the loop (MarcoFalke) - #8400 `bea02dc` enable rpcbind_test (yurizhykin) - #8417 `f70be14` Add walletdump RPC test (including HD- & encryption-tests) (jonasschnelli) - #8419 `a7aa3cc` Enable size accounting in mining unit tests (sdaftuar) - #8442 `8bb1efd` Rework hd wallet dump test (MarcoFalke) - #8528 `3606b6b` Update p2p-segwit.py to reflect correct behavior (instagibbs) - #8531 `a27cdd8` abandonconflict: Use assert_equal (MarcoFalke) - #8667 `6b07362` Fix SIGHASH_SINGLE bug in test_framework SignatureHash (jl2012) - #8673 `03b0196` Fix obvious assignment/equality error in test (JeremyRubin) - #8739 `cef633c` Fix broken sendcmpct test in p2p-compactblocks.py (sdaftuar) - #8418 `ff893aa` Add tests for compact blocks (sdaftuar) - #8803 `375437c` Ping regularly in p2p-segwit.py to keep connection alive (jl2012) - #8827 `9bbe66e` Split up slow RPC calls to avoid pruning test timeouts (sdaftuar) - #8829 `2a8bca4` Add bitcoin-tx JSON tests (jnewbery) - #8834 `1dd1783` blockstore: Switch to dumb dbm (MarcoFalke) - #8835 `d87227d` nulldummy.py: Don't run unused code (MarcoFalke) - #8836 `eb18cc1` bitcoin-util-test.py should fail if the output file is empty (jnewbery) - #8839 `31ab2f8` Avoid ConnectionResetErrors during RPC tests (laanwj) - #8840 `cbc3fe5` Explicitly set encoding to utf8 when opening text files (laanwj) - #8841 `3e4abb5` Fix nulldummy test (jl2012) - #8854 `624a007` Fix race condition in p2p-compactblocks test (sdaftuar) - #8857 `1f60d45` mininode: Only allow named args in wait_until (MarcoFalke) - #8860 `0bee740` util: Move wait_bitcoinds() into stop_nodes() (MarcoFalke) - #8882 `b73f065` Fix race conditions in p2p-compactblocks.py and sendheaders.py (sdaftuar) - #8904 `cc6f551` Fix compact block shortids for a test case (dagurval) ### Documentation - #8754 `0e2c6bd` Target protobuf 2.6 in OS X build notes. (fanquake) - #8461 `b17a3f9` Document return value of networkhashps for getmininginfo RPC endpoint (jlopp) - #8512 `156e305` Corrected JSON typo on setban of net.cpp (sevastos) - #8683 `8a7d7ff` Fix incorrect file name bitcoin.qrc (bitcoinsSG) - #8891 `5e0dd9e` Update bips.md for Segregated Witness (fanquake) - #8545 `863ae74` Update git-subtree-check.sh README (MarcoFalke) - #8607 `486650a` Fix doxygen off-by-one comments, fix typos (MarcoFalke) - #8560 `c493f43` Fix two VarInt examples in serialize.h (cbarcenas) - #8737 `084cae9` UndoReadFromDisk works on undo files (rev), not on block files (paveljanik) - #8625 `0a35573` Clarify statement about parallel jobs in rpc-tests.py (isle2983) - #8624 `0e6d753` build: Mention curl (MarcoFalke) - #8604 `b09e13c` build,doc: Update for 0.13.0+ and OpenBSD 5.9 (laanwj) - #8939 `06d15fb` Update implemented bips for 0.13.1 (sipa) ### Miscellaneous - #8742 `d31ac72` Specify Protobuf version 2 in paymentrequest.proto (fanquake) - #8414,#8558,#8676,#8700,#8701,#8702 Add missing copyright headers (isle2983, kazcw) - #8899 `4ed2627` Fix wake from sleep issue with Boost 1.59.0 (fanquake) - #8817 `bcf3806` update bitcoin-tx to output witness data (jnewbery) - #8513 `4e5fc31` Fix a type error that would not compile on OSX. (JeremyRubin) - #8392 `30eac2d` Fix several node initialization issues (sipa) - #8548 `305d8ac` Use `__func__` to get function name for output printing (MarcoFalke) - #8291 `a987431` [util] CopyrightHolders: Check for untranslated substitution (MarcoFalke) Credits ======= Thanks to everyone who directly contributed to this release: - adlawren - Alexey Vesnin - Anders Øyvind Urke-Sætre - Andrew Chow - Anthony Towns - BtcDrak - Chris Stewart - Christian Barcenas - Christian Decker - Cory Fields - crowning- - Dagur Valberg Johannsson - David A. Harding - Eric Lombrozo - Ethan Heilman - fanquake - Gaurav Rana - Gregory Maxwell - instagibbs - isle2983 - Jameson Lopp - Jeremy Rubin - jnewbery - Johnson Lau - Jonas Schnelli - jonnynewbs - Justin Camarena - Kaz Wesley - leijurv - Luke Dashjr - MarcoFalke - Marty Jones - Matt Corallo - Micha - Michael Ford - mruddy - Pavel Janík - Pieter Wuille - rodasmith - Sev - Suhas Daftuar - whythat - Wladimir J. van der Laan As well as everyone that helped translating on [Transifex](https://www.transifex.com/projects/p/bitcoin/).