release-notes-0.11.2.md
1 Bitcoin Core version 0.11.2 is now available from: 2 3 <https://bitcoin.org/bin/bitcoin-core-0.11.2/> 4 5 This is a new minor version release, bringing bug fixes, the BIP65 6 (CLTV) consensus change, and relay policy preparation for BIP113. It is 7 recommended to upgrade to this version as soon as possible. 8 9 Please report bugs using the issue tracker at github: 10 11 <https://github.com/bitcoin/bitcoin/issues> 12 13 Upgrading and downgrading 14 ========================= 15 16 How to Upgrade 17 -------------- 18 19 If you are running an older version, shut it down. Wait until it has completely 20 shut down (which might take a few minutes for older versions), then run the 21 installer (on Windows) or just copy over /Applications/Bitcoin-Qt (on Mac) or 22 bitcoind/bitcoin-qt (on Linux). 23 24 Downgrade warning 25 ------------------ 26 27 Because release 0.10.0 and later makes use of headers-first synchronization and 28 parallel block download (see further), the block files and databases are not 29 backwards-compatible with pre-0.10 versions of Bitcoin Core or other software: 30 31 * Blocks will be stored on disk out of order (in the order they are 32 received, really), which makes it incompatible with some tools or 33 other programs. Reindexing using earlier versions will also not work 34 anymore as a result of this. 35 36 * The block index database will now hold headers for which no block is 37 stored on disk, which earlier versions won't support. 38 39 If you want to be able to downgrade smoothly, make a backup of your entire data 40 directory. Without this your node will need start syncing (or importing from 41 bootstrap.dat) anew afterwards. It is possible that the data from a completely 42 synchronised 0.10 node may be usable in older versions as-is, but this is not 43 supported and may break as soon as the older version attempts to reindex. 44 45 This does not affect wallet forward or backward compatibility. There are no 46 known problems when downgrading from 0.11.x to 0.10.x. 47 48 Notable changes since 0.11.1 49 ============================ 50 51 BIP65 soft fork to enforce OP_CHECKLOCKTIMEVERIFY opcode 52 -------------------------------------------------------- 53 54 This release includes several changes related to the [BIP65][] soft fork 55 which redefines the existing OP_NOP2 opcode as OP_CHECKLOCKTIMEVERIFY 56 (CLTV) so that a transaction output can be made unspendable until a 57 specified point in the future. 58 59 1. This release will only relay and mine transactions spending a CLTV 60 output if they comply with the BIP65 rules as provided in code. 61 62 2. This release will produce version 4 blocks by default. Please see the 63 *notice to miners* below. 64 65 3. Once 951 out of a sequence of 1,001 blocks on the local node's best block 66 chain contain version 4 (or higher) blocks, this release will no 67 longer accept new version 3 blocks and it will only accept version 4 68 blocks if they comply with the BIP65 rules for CLTV. 69 70 For more information about the soft-forking change, please see 71 <https://github.com/bitcoin/bitcoin/pull/6351> 72 73 Graphs showing the progress towards block version 4 adoption may be 74 found at the URLs below: 75 76 - Block versions over the last 50,000 blocks as progress towards BIP65 77 consensus enforcement: <http://bitcoin.sipa.be/ver-50k.png> 78 79 - Block versions over the last 2,000 blocks showing the days to the 80 earliest possible BIP65 consensus-enforced block: <http://bitcoin.sipa.be/ver-2k.png> 81 82 **Notice to miners:** Bitcoin Core’s block templates are now for 83 version 4 blocks only, and any mining software relying on its 84 getblocktemplate must be updated in parallel to use libblkmaker either 85 version 0.4.3 or any version from 0.5.2 onward. 86 87 - If you are solo mining, this will affect you the moment you upgrade 88 Bitcoin Core, which must be done prior to BIP65 achieving its 951/1001 89 status. 90 91 - If you are mining with the stratum mining protocol: this does not 92 affect you. 93 94 - If you are mining with the getblocktemplate protocol to a pool: this 95 will affect you at the pool operator’s discretion, which must be no 96 later than BIP65 achieving its 951/1001 status. 97 98 [BIP65]: https://github.com/bitcoin/bips/blob/master/bip-0065.mediawiki 99 100 BIP113 mempool-only locktime enforcement using GetMedianTimePast() 101 ---------------------------------------------------------------- 102 103 Bitcoin transactions currently may specify a locktime indicating when 104 they may be added to a valid block. Current consensus rules require 105 that blocks have a block header time greater than the locktime specified 106 in any transaction in that block. 107 108 Miners get to choose what time they use for their header time, with the 109 consensus rule being that no node will accept a block whose time is more 110 than two hours in the future. This creates a incentive for miners to 111 set their header times to future values in order to include locktimed 112 transactions which weren't supposed to be included for up to two more 113 hours. 114 115 The consensus rules also specify that valid blocks may have a header 116 time greater than that of the median of the 11 previous blocks. This 117 GetMedianTimePast() time has a key feature we generally associate with 118 time: it can't go backwards. 119 120 [BIP113][] specifies a soft fork (**not enforced in this release**) that 121 weakens this perverse incentive for individual miners to use a future 122 time by requiring that valid blocks have a computed GetMedianTimePast() 123 greater than the locktime specified in any transaction in that block. 124 125 Mempool inclusion rules currently require transactions to be valid for 126 immediate inclusion in a block in order to be accepted into the mempool. 127 This release begins applying the BIP113 rule to received transactions, 128 so transaction whose time is greater than the GetMedianTimePast() will 129 no longer be accepted into the mempool. 130 131 **Implication for miners:** you will begin rejecting transactions that 132 would not be valid under BIP113, which will prevent you from producing 133 invalid blocks if/when BIP113 is enforced on the network. Any 134 transactions which are valid under the current rules but not yet valid 135 under the BIP113 rules will either be mined by other miners or delayed 136 until they are valid under BIP113. Note, however, that time-based 137 locktime transactions are more or less unseen on the network currently. 138 139 **Implication for users:** GetMedianTimePast() always trails behind the 140 current time, so a transaction locktime set to the present time will be 141 rejected by nodes running this release until the median time moves 142 forward. To compensate, subtract one hour (3,600 seconds) from your 143 locktimes to allow those transactions to be included in mempools at 144 approximately the expected time. 145 146 [BIP113]: https://github.com/bitcoin/bips/blob/master/bip-0113.mediawiki 147 148 Windows bug fix for corrupted UTXO database on unclean shutdowns 149 ---------------------------------------------------------------- 150 151 Several Windows users reported that they often need to reindex the 152 entire blockchain after an unclean shutdown of Bitcoin Core on Windows 153 (or an unclean shutdown of Windows itself). Although unclean shutdowns 154 remain unsafe, this release no longer relies on memory-mapped files for 155 the UTXO database, which significantly reduced the frequency of unclean 156 shutdowns leading to required reindexes during testing. 157 158 For more information, see: <https://github.com/bitcoin/bitcoin/pull/6917> 159 160 Other fixes for database corruption on Windows are expected in the 161 next major release. 162 163 0.11.2 Change log 164 ================= 165 166 Detailed release notes follow. This overview includes changes that affect 167 behavior, not code moves, refactors and string updates. For convenience in locating 168 the code changes and accompanying discussion, both the pull request and 169 git merge commit are mentioned. 170 171 - #6124 `684636b` Make CScriptNum() take nMaxNumSize as an argument 172 - #6124 `4fa7a04` Replace NOP2 with CHECKLOCKTIMEVERIFY (BIP65) 173 - #6124 `6ea5ca4` Enable CHECKLOCKTIMEVERIFY as a standard script verify flag 174 - #6351 `5e82e1c` Add CHECKLOCKTIMEVERIFY (BIP65) soft-fork logic 175 - #6353 `ba1da90` Show softfork status in getblockchaininfo 176 - #6351 `6af25b0` Add BIP65 to getblockchaininfo softforks list 177 - #6688 `01878c9` Fix locking in GetTransaction 178 - #6653 `b3eaa30` [Qt] Raise debug window when requested 179 - #6600 `1e672ae` Debian/Ubuntu: Include bitcoin-tx binary 180 - #6600 `2394f4d` Debian/Ubuntu: Split bitcoin-tx into its own package 181 - #5987 `33d6825` Bugfix: Allow mining on top of old tip blocks for testnet 182 - #6852 `21e58b8` build: make sure OpenSSL heeds noexecstack 183 - #6846 `af6edac` alias `-h` for `--help` 184 - #6867 `95a5039` Set TCP_NODELAY on P2P sockets. 185 - #6856 `dfe55bd` Do not allow blockfile pruning during reindex. 186 - #6566 `a1d3c6f` Add rules--presently disabled--for using GetMedianTimePast as end point for lock-time calculations 187 - #6566 `f720c5f` Enable policy enforcing GetMedianTimePast as the end point of lock-time constraints 188 - #6917 `0af5b8e` leveldb: Win32WritableFile without memory mapping 189 - #6948 `4e895b0` Always flush block and undo when switching to new file 190 191 Credits 192 ======= 193 194 Thanks to everyone who directly contributed to this release: 195 196 - Alex Morcos 197 - ฿tcDrak 198 - Chris Kleeschulte 199 - Daniel Cousens 200 - Diego Viola 201 - Eric Lombrozo 202 - Esteban Ordano 203 - Gregory Maxwell 204 - Luke Dashjr 205 - Marco Falke 206 - Mark Friedenbach 207 - Matt Corallo 208 - Micha 209 - Mitchell Cash 210 - Peter Todd 211 - Pieter Wuille 212 - Wladimir J. van der Laan 213 - Zak Wilcox 214 215 And those who contributed additional code review and/or security research. 216 217 As well as everyone that helped translating on [Transifex](https://www.transifex.com/projects/p/bitcoin/).