diff --git a/doc/litecoin-release-notes/release-notes-0.13.2.md b/doc/litecoin-release-notes/release-notes-0.13.2.md new file mode 100644 index 0000000000..619183a3a3 --- /dev/null +++ b/doc/litecoin-release-notes/release-notes-0.13.2.md @@ -0,0 +1,993 @@ +Litecoin Core version 0.13.2 is now available from: + + + +This is a new major version release, including new features, various bugfixes and performance improvements, as well as updated translations. +It is recommended to upgrade to this version. + +Please report bugs using the issue tracker at github: + + + +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 litecoin +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 +=============== + +Signature validation using libsecp256k1 +--------------------------------------- + +ECDSA signatures inside Litecoin transactions now use validation using +[libsecp256k1](https://github.com/bitcoin-core/secp256k1) instead of OpenSSL. + +Depending on the platform, this means a significant speedup for raw signature +validation speed. The advantage is largest on x86_64, where validation is over +five times faster. In practice, this translates to a raw reindexing and new +block validation times that are less than half of what it was before. + +Libsecp256k1 has undergone very extensive testing and validation. + +A side effect of this change is that libconsensus no longer depends on OpenSSL. + +Reduce upload traffic +--------------------- + +A major part of the outbound traffic is caused by serving historic blocks to +other nodes in initial block download state. + +It is now possible to reduce the total upload traffic via the `-maxuploadtarget` +parameter. This is *not* a hard limit but a threshold to minimize the outbound +traffic. When the limit is about to be reached, the uploaded data is cut by not +serving historic blocks (blocks older than one week). +Moreover, any SPV peer is disconnected when they request a filtered block. + +This option can be specified in MiB per day and is turned off by default +(`-maxuploadtarget=0`). +The recommended minimum is 144 * MAX_BLOCK_SIZE (currently 144MB) per day. + +Whitelisted peers will never be disconnected, although their traffic counts for +calculating the target. + +A more detailed documentation about keeping traffic low can be found in +[/doc/reduce-traffic.md](/doc/reduce-traffic.md). + +Direct headers announcement (BIP 130) +------------------------------------- + +Between compatible peers, [BIP 130] +(https://github.com/bitcoin/bips/blob/master/bip-0130.mediawiki) +direct headers announcement is used. This means that blocks are advertised by +announcing their headers directly, instead of just announcing the hash. In a +reorganization, all new headers are sent, instead of just the new tip. This +can often prevent an extra roundtrip before the actual block is downloaded. + +Memory pool limiting +-------------------- + +Previous versions of Litecoin Core had their mempool limited by checking +a transaction's fees against the node's minimum relay fee. There was no +upper bound on the size of the mempool and attackers could send a large +number of transactions paying just slighly more than the default minimum +relay fee to crash nodes with relatively low RAM. A temporary workaround +for previous versions of Litecoin Core was to raise the default minimum +relay fee. + +Litecoin Core 0.13.2 will have a strict maximum size on the mempool. The +default value is 300 MB and can be configured with the `-maxmempool` +parameter. Whenever a transaction would cause the mempool to exceed +its maximum size, the transaction that (along with in-mempool descendants) has +the lowest total feerate (as a package) will be evicted and the node's effective +minimum relay feerate will be increased to match this feerate plus the initial +minimum relay feerate. The initial minimum relay feerate is set to +1000 satoshis per kB. + +Litecoin Core 0.13.2 also introduces new default policy limits on the length and +size of unconfirmed transaction chains that are allowed in the mempool +(generally limiting the length of unconfirmed chains to 25 transactions, with a +total size of 101 KB). These limits can be overriden using command line +arguments; see the extended help (`--help -help-debug`) for more information. + +RPC: Random-cookie RPC authentication +------------------------------------- + +When no `-rpcpassword` is specified, the daemon now uses a special 'cookie' +file for authentication. This file is generated with random content when the +daemon starts, and deleted when it exits. Its contents are used as +authentication token. Read access to this file controls who can access through +RPC. By default it is stored in the data directory but its location can be +overridden with the option `-rpccookiefile`. + +This is similar to Tor's CookieAuthentication: see +https://www.torproject.org/docs/tor-manual.html.en + +This allows running litecoind without having to do any manual configuration. + +Relay: Any sequence of pushdatas in OP_RETURN outputs now allowed +----------------------------------------------------------------- + +Previously OP_RETURN outputs with a payload were only relayed and mined if they +had a single pushdata. This restriction has been lifted to allow any +combination of data pushes and numeric constant opcodes (OP_1 to OP_16) after +the OP_RETURN. The limit on OP_RETURN output size is now applied to the entire +serialized scriptPubKey, 83 bytes by default. (the previous 80 byte default plus +three bytes overhead) + +Relay: New and only new blocks relayed when pruning +--------------------------------------------------- + +When running in pruned mode, the client will now relay new blocks. When +responding to the `getblocks` message, only hashes of blocks that are on disk +and are likely to remain there for some reasonable time window (1 hour) will be +returned (previously all relevant hashes were returned). + +Relay and Mining: Priority transactions +--------------------------------------- + +Litecoin Core has a heuristic 'priority' based on coin value and age. This +calculation is used for relaying of transactions which do not pay the +minimum relay fee, and can be used as an alternative way of sorting +transactions for mined blocks. Litecoin Core will relay transactions with +insufficient fees depending on the setting of `-limitfreerelay=` (default: +`r=15` kB per minute) and `-blockprioritysize=`. + +In Bitcoin Core 0.12, when mempool limit has been reached a higher minimum +relay fee takes effect to limit memory usage. Transactions which do not meet +this higher effective minimum relay fee will not be relayed or mined even if +they rank highly according to the priority heuristic. + +The mining of transactions based on their priority is also now disabled by +default. To re-enable it, simply set `-blockprioritysize=` where is the size +in bytes of your blocks to reserve for these transactions. The old default was +50k, so to retain approximately the same policy, you would set +`-blockprioritysize=50000`. + +Additionally, as a result of computational simplifications, the priority value +used for transactions received with unconfirmed inputs is lower than in prior +versions due to avoiding recomputing the amounts as input transactions confirm. + +External miner policy set via the `prioritisetransaction` RPC to rank +transactions already in the mempool continues to work as it has previously. +Note, however, that if mining priority transactions is left disabled, the +priority delta will be ignored and only the fee metric will be effective. + +This internal automatic prioritization handling is being considered for removal +entirely in Litecoin Core 0.13, and it is at this time undecided whether the +more accurate priority calculation for chained unconfirmed transactions will be +restored. Community direction on this topic is particularly requested to help +set project priorities. + +Automatically use Tor hidden services +------------------------------------- + +Starting with Tor version 0.2.7.1 it is possible, through Tor's control socket +API, to create and destroy 'ephemeral' hidden services programmatically. +Litecoin Core has been updated to make use of this. + +This means that if Tor is running (and proper authorization is available), +Litecoin Core automatically creates a hidden service to listen on, without +manual configuration. Litecoin Core will also use Tor automatically to connect +to other .onion nodes if the control socket can be successfully opened. This +will positively affect the number of available .onion nodes and their usage. + +This new feature is enabled by default if Litecoin Core is listening, and +a connection to Tor can be made. It can be configured with the `-listenonion`, +`-torcontrol` and `-torpassword` settings. To show verbose debugging +information, pass `-debug=tor`. + +Notifications through ZMQ +------------------------- + +Litecoind can now (optionally) asynchronously notify clients through a +ZMQ-based PUB socket of the arrival of new transactions and blocks. +This feature requires installation of the ZMQ C API library 4.x and +configuring its use through the command line or configuration file. +Please see [docs/zmq.md](/doc/zmq.md) for details of operation. + +Wallet: Transaction fees +------------------------ + +Various improvements have been made to how the wallet calculates +transaction fees. + +Users can decide to pay a predefined fee rate by setting `-paytxfee=` +(or `settxfee ` rpc during runtime). A value of `n=0` signals Litecoin +Core to use floating fees. By default, Litecoin Core will use floating +fees. + +Based on past transaction data, floating fees approximate the fees +required to get into the `m`th block from now. This is configurable +with `-txconfirmtarget=` (default: `2`). + +Sometimes, it is not possible to give good estimates, or an estimate +at all. Therefore, a fallback value can be set with `-fallbackfee=` +(default: `0.0002` LTC/kB). + +At all times, Litecoin Core will cap fees at `-maxtxfee=` (default: +0.10) LTC. +Furthermore, Litecoin Core will never create transactions paying less than +the current minimum relay fee. +Finally, a user can set the minimum fee rate for all transactions with +`-mintxfee=`, which defaults to 1000 satoshis per kB. + +Wallet: Negative confirmations and conflict detection +----------------------------------------------------- + +The wallet will now report a negative number for confirmations that indicates +how deep in the block chain the conflict is found. For example, if a transaction +A has 5 confirmations and spends the same input as a wallet transaction B, B +will be reported as having -5 confirmations. If another wallet transaction C +spends an output from B, it will also be reported as having -5 confirmations. +To detect conflicts with historical transactions in the chain a one-time +`-rescan` may be needed. + +Unlike earlier versions, unconfirmed but non-conflicting transactions will never +get a negative confirmation count. They are not treated as spendable unless +they're coming from ourself (change) and accepted into our local mempool, +however. The new "trusted" field in the `listtransactions` RPC output +indicates whether outputs of an unconfirmed transaction are considered +spendable. + +Wallet: Merkle branches removed +------------------------------- + +Previously, every wallet transaction stored a Merkle branch to prove its +presence in blocks. This wasn't being used for more than an expensive +sanity check. Since 0.13.2, these are no longer stored. When loading a +0.13.2 wallet into an older version, it will automatically rescan to avoid +failed checks. + +Wallet: Pruning +--------------- + +With 0.13.2 it is possible to use wallet functionality in pruned mode. +This can reduce the disk usage from currently around 6 GB to +around 0.2 GB. + +However, rescans as well as the RPCs `importwallet`, `importaddress`, +`importprivkey` are disabled. + +To enable block pruning set `prune=` on the command line or in +`litecoin.conf`, where `N` is the number of MiB to allot for +raw block & undo data. + +A value of 0 disables pruning. The minimal value above 0 is 550. Your +wallet is as secure with high values as it is with low ones. Higher +values merely ensure that your node will not shut down upon blockchain +reorganizations of more than 2 days - which are unlikely to happen in +practice. In future releases, a higher value may also help the network +as a whole: stored blocks could be served to other nodes. + +For further information about pruning, you may also consult the [release +notes of Bitcoin Core v0.11.0](https://github.com/bitcoin/bitcoin/blob/v0.11.0/doc/release-notes.md#block-file-pruning). + +`NODE_BLOOM` service bit +------------------------ + +Support for the `NODE_BLOOM` service bit, as described in [BIP +111](https://github.com/bitcoin/bips/blob/master/bip-0111.mediawiki), has been +added to the P2P protocol code. + +BIP 111 defines a service bit to allow peers to advertise that they support +bloom filters (such as used by SPV clients) explicitly. It also bumps the protocol +version to allow peers to identify old nodes which allow bloom filtering of the +connection despite lacking the new service bit. + +In this version, it is only enforced for peers that send protocol versions +`>=70011`. For the next major version it is planned that this restriction will be +removed. It is recommended to update SPV clients to check for the `NODE_BLOOM` +service bit for nodes that report versions newer than 70011. + +Option parsing behavior +----------------------- + +Command line options are now parsed strictly in the order in which they are +specified. It used to be the case that `-X -noX` ends up, unintuitively, with X +set, as `-X` had precedence over `-noX`. This is no longer the case. Like for +other software, the last specified value for an option will hold. + +RPC: Low-level API changes +-------------------------- + +- Monetary amounts can be provided as strings. This means that for example the + argument to sendtoaddress can be "0.0001" instead of 0.0001. This can be an + advantage if a JSON library insists on using a lossy floating point type for + numbers, which would be dangerous for monetary amounts. + +* The `asm` property of each scriptSig now contains the decoded signature hash + type for each signature that provides a valid defined hash type. + +* OP_NOP2 has been renamed to OP_CHECKLOCKTIMEVERIFY by [BIP 65](https://github.com/bitcoin/bips/blob/master/bip-0065.mediawiki) + +The following items contain assembly representations of scriptSig signatures +and are affected by this change: + +- RPC `getrawtransaction` +- RPC `decoderawtransaction` +- RPC `decodescript` +- REST `/rest/tx/` (JSON format) +- REST `/rest/block/` (JSON format when including extended tx details) +- `litecoin-tx -json` + +For example, the `scriptSig.asm` property of a transaction input that +previously showed an assembly representation of: + + 304502207fa7a6d1e0ee81132a269ad84e68d695483745cde8b541e3bf630749894e342a022100c1f7ab20e13e22fb95281a870f3dcf38d782e53023ee313d741ad0cfbc0c509001 400000 OP_NOP2 + +now shows as: + + 304502207fa7a6d1e0ee81132a269ad84e68d695483745cde8b541e3bf630749894e342a022100c1f7ab20e13e22fb95281a870f3dcf38d782e53023ee313d741ad0cfbc0c5090[ALL] 400000 OP_CHECKLOCKTIMEVERIFY + +Note that the output of the RPC `decodescript` did not change because it is +configured specifically to process scriptPubKey and not scriptSig scripts. + +RPC: SSL support dropped +------------------------ + +SSL support for RPC, previously enabled by the option `rpcssl` has been dropped +from both the client and the server. This was done in preparation for removing +the dependency on OpenSSL for the daemon completely. + +Trying to use `rpcssl` will result in an error: + + Error: SSL mode for RPC (-rpcssl) is no longer supported. + +If you are one of the few people that relies on this feature, a flexible +migration path is to use `stunnel`. This is an utility that can tunnel +arbitrary TCP connections inside SSL. On e.g. Ubuntu it can be installed with: + + sudo apt-get install stunnel4 + +Then, to tunnel a SSL connection on 29332 to a RPC server bound on localhost on port 19334 do: + + stunnel -d 29332 -r 127.0.0.1:19334 -p stunnel.pem -P '' + +It can also be set up system-wide in inetd style. + +Another way to re-attain SSL would be to setup a httpd reverse proxy. This solution +would allow the use of different authentication, loadbalancing, on-the-fly compression and +caching. A sample config for apache2 could look like: + + Listen 443 + + NameVirtualHost *:443 + + + SSLEngine On + SSLCertificateFile /etc/apache2/ssl/server.crt + SSLCertificateKeyFile /etc/apache2/ssl/server.key + + + ProxyPass http://127.0.0.1:9332/ + ProxyPassReverse http://127.0.0.1:9332/ + # optional enable digest auth + # AuthType Digest + # ... + + # optional bypass litecoind rpc basic auth + # RequestHeader set Authorization "Basic " + # get the from the shell with: base64 <<< litecoinrpc: + + + # Or, balance the load: + # ProxyPass / balancer://balancer_cluster_name + + + +Other P2P Changes +----------------- + +The list of banned peers is now stored on disk rather than in memory. +Restarting litecoind will no longer clear out the list of banned peers; instead +a new RPC call (`clearbanned`) can be used to manually clear the list. The new +`setban` RPC call can also be used to manually ban or unban a peer. + +Database cache memory increased +-------------------------------- + +As a result of growth of the UTXO set, performance with the prior default +database cache of 100 MiB has suffered. +For this reason the default was changed to 300 MiB in this release. + +For nodes on low-memory systems, the database cache can be changed back to +100 MiB (or to another value) by either: + +- Adding `dbcache=100` in litecoin.conf +- Changing it in the GUI under `Options → Size of database cache` + +Note that the database cache setting has the most performance impact +during initial sync of a node, and when catching up after downtime. + + +litecoin-cli: arguments privacy +------------------------------ + +The RPC command line client gained a new argument, `-stdin` +to read extra arguments from standard input, one per line until EOF/Ctrl-D. +For example: + + $ src/litecoin-cli -stdin walletpassphrase + mysecretcode + 120 + ..... press Ctrl-D here to end input + $ + +It is recommended to use this for sensitive information such as wallet +passphrases, as command-line arguments can usually be read from the process +table by any user on the system. + + +C++11 and Python 3 +------------------ + +Various code modernizations have been done. The Litecoin Core code base has +started using C++11. This means that a C++11-capable compiler is now needed for +building. Effectively this means GCC 4.7 or higher, or Clang 3.3 or higher. + +When cross-compiling for a target that doesn't have C++11 libraries, configure with +`./configure --enable-glibc-back-compat ... LDFLAGS=-static-libstdc++`. + +For running the functional tests in `qa/rpc-tests`, Python3.4 or higher is now +required. + + +Linux ARM builds +---------------- + +Due to popular request, Linux ARM builds have been added to the uploaded +executables. + +The following extra files can be found in the download directory or torrent: + +- `litecoin-${VERSION}-arm-linux-gnueabihf.tar.gz`: Linux binaries for the most + common 32-bit ARM architecture. +- `litecoin-${VERSION}-aarch64-linux-gnu.tar.gz`: Linux binaries for the most + common 64-bit ARM 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 Android is not considered ARM Linux in this context. The executables +are not expected to work out of the box on Android. + +BIP68 soft fork to enforce sequence locks for relative locktime +--------------------------------------------------------------- + +[BIP68][] introduces relative lock-time consensus-enforced semantics of +the sequence number field to enable a signed transaction input to remain +invalid for a defined period of time after confirmation of its corresponding +outpoint. + +For more information about the implementation, see + + +BIP112 soft fork to enforce OP_CHECKSEQUENCEVERIFY +-------------------------------------------------- + +[BIP112][] redefines the existing OP_NOP3 as OP_CHECKSEQUENCEVERIFY (CSV) +for a new opcode in the Litecoin scripting system that in combination with +[BIP68][] allows execution pathways of a script to be restricted based +on the age of the output being spent. + +For more information about the implementation, see + + +BIP113 locktime enforcement soft fork +------------------------------------- + +This release seeks to make mempool-only locktime enforcement using GetMedianTimePast() +a consensus rule. + +Litecoin transactions currently may specify a locktime indicating when +they may be added to a valid block. Current consensus rules require +that blocks have a block header time greater than the locktime specified +in any transaction in that block. + +Miners get to choose what time they use for their header time, with the +consensus rule being that no node will accept a block whose time is more +than two hours in the future. This creates a incentive for miners to +set their header times to future values in order to include locktimed +transactions which weren't supposed to be included for up to two more +hours. + +The consensus rules also specify that valid blocks may have a header +time greater than that of the median of the 11 previous blocks. This +GetMedianTimePast() time has a key feature we generally associate with +time: it can't go backwards. + +[BIP113][] specifies a soft fork enforced in this release that +weakens this perverse incentive for individual miners to use a future +time by requiring that valid blocks have a computed GetMedianTimePast() +greater than the locktime specified in any transaction in that block. + +Mempool inclusion rules currently require transactions to be valid for +immediate inclusion in a block in order to be accepted into the mempool. +This release begins applying the BIP113 rule to received transactions, +so transaction whose time is greater than the GetMedianTimePast() will +no longer be accepted into the mempool. + +**Implication for miners:** you will begin rejecting transactions that +would not be valid under BIP113, which will prevent you from producing +invalid blocks when BIP113 is enforced on the network. Any +transactions which are valid under the current rules but not yet valid +under the BIP113 rules will either be mined by other miners or delayed +until they are valid under BIP113. Note, however, that time-based +locktime transactions are more or less unseen on the network currently. + +**Implication for users:** GetMedianTimePast() always trails behind the +current time, so a transaction locktime set to the present time will be +rejected by nodes running this release until the median time moves +forward. To compensate, subtract one hour (3,600 seconds) from your +locktimes to allow those transactions to be included in mempools at +approximately the expected time. + +For more information about the implementation, see + + + +Compact Block support (BIP 152) +------------------------------- + +Support for block relay using the Compact Blocks protocol has been implemented +in PR 8068. + +The primary goal is reducing the bandwidth spikes at relay time, though in many +cases it also reduces propagation delay. It is automatically enabled between +compatible peers. +[BIP 152](https://github.com/bitcoin/bips/blob/master/bip-0152.mediawiki) + +As a side-effect, ordinary non-mining nodes will download and upload blocks +faster if those blocks were produced by miners using similar transaction +filtering policies. This means that a miner who produces a block with many +transactions discouraged by your node will be relayed slower than one with +only transactions already in your memory pool. The overall effect of such +relay differences on the network may result in blocks which include widely- +discouraged transactions losing a stale block race, and therefore miners may +wish to configure their node to take common relay policies into consideration. + + +Hierarchical Deterministic Key Generation +----------------------------------------- +Newly created wallets will use hierarchical deterministic key generation +according to BIP32 (keypath m/0'/0'/k'). +Existing wallets will still use traditional key generation. + +Backups of HD wallets, regardless of when they have been created, can +therefore be used to re-generate all possible private keys, even the +ones which haven't already been generated during the time of the backup. +**Attention:** Encrypting the wallet will create a new seed which requires +a new backup! + +Wallet dumps (created using the `dumpwallet` RPC) will contain the deterministic +seed. This is expected to allow future versions to import the seed and all +associated funds, but this is not yet implemented. + +HD key generation for new wallets can be disabled by `-usehd=0`. Keep in +mind that this flag only has affect on newly created wallets. +You can't disable HD key generation once you have created a HD wallet. + +There is no distinction between internal (change) and external keys. + +HD wallets are incompatible with older versions of Litecoin Core. + +[Pull request](https://github.com/bitcoin/bitcoin/pull/8035/files), [BIP 32](https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki) + + +Mining transaction selection ("Child Pays For Parent") +------------------------------------------------------ + +The mining transaction selection algorithm has been replaced with an algorithm +that selects transactions based on their feerate inclusive of unconfirmed +ancestor transactions. This means that a low-fee transaction can become more +likely to be selected if a high-fee transaction that spends its outputs is +relayed. + +With this change, the `-blockminsize` command line option has been removed. + +The command line option `-blockmaxsize` remains an option to specify the +maximum number of serialized bytes in a generated block. In addition, the new +command line option `-blockmaxweight` has been added, which specifies the +maximum "block weight" of a generated block, as defined by [BIP 141 (Segregated +Witness)] (https://github.com/bitcoin/bips/blob/master/bip-0141.mediawiki). + +In preparation for Segregated Witness, the mining algorithm has been modified +to optimize transaction selection for a given block weight, rather than a given +number of serialized bytes in a block. In this release, transaction selection +is unaffected by this distinction (as BIP 141 activation is not supported on +mainnet in this release, see above), but in future releases and after BIP 141 +activation, these calculations would be expected to differ. + +For optimal runtime performance, miners using this release should specify +`-blockmaxweight` on the command line, and not specify `-blockmaxsize`. +Additionally (or only) specifying `-blockmaxsize`, or relying on default +settings for both, may result in performance degradation, as the logic to +support `-blockmaxsize` performs additional computation to ensure that +constraint is met. (Note that for mainnet, in this release, the equivalent +parameter for `-blockmaxweight` would be four times the desired +`-blockmaxsize`. See [BIP 141] +(https://github.com/bitcoin/bips/blob/master/bip-0141.mediawiki) for additional +details.) + +In the future, the `-blockmaxsize` option may be removed, as block creation is +no longer optimized for this metric. Feedback is requested on whether to +deprecate or keep this command line option in future releases. + + +Reindexing changes +------------------ + +In earlier versions, reindexing did validation while reading through the block +files on disk. These two have now been split up, so that all blocks are known +before validation starts. This was necessary to make certain optimizations that +are available during normal synchronizations also available during reindexing. + +The two phases are distinct in the Litecoin-Qt GUI. During the first one, +"Reindexing blocks on disk" is shown. During the second (slower) one, +"Processing blocks on disk" is shown. + +It is possible to only redo validation now, without rebuilding the block index, +using the command line option `-reindex-chainstate` (in addition to +`-reindex` which does both). This new option is useful when the blocks on disk +are assumed to be fine, but the chainstate is still corrupted. It is also +useful for benchmarks. + + +Removal of internal miner +-------------------------- + +As CPU mining has been useless for a long time, the internal miner has been +removed in this release, and replaced with a simpler implementation for the +test framework. + +The overall result of this is that `setgenerate` RPC call has been removed, as +well as the `-gen` and `-genproclimit` command-line options. + +For testing, the `generate` call can still be used to mine a block, and a new +RPC call `generatetoaddress` has been added to mine to a specific address. This +works with wallet disabled. + + +New bytespersigop implementation +-------------------------------- + +The former implementation of the bytespersigop filter accidentally broke bare +multisig (which is meant to be controlled by the `permitbaremultisig` option), +since the consensus protocol always counts these older transaction forms as 20 +sigops for backwards compatibility. Simply fixing this bug by counting more +accurately would have reintroduced a vulnerability. It has therefore been +replaced with a new implementation that rather than filter such transactions, +instead treats them (for fee purposes only) as if they were in fact the size +of a transaction actually using all 20 sigops. + + +Low-level P2P changes +---------------------- + +- The optional new p2p message "feefilter" is implemented and the protocol + version is bumped to 70013. Upon receiving a feefilter message from a peer, + a node will not send invs for any transactions which do not meet the filter + feerate. [BIP 133](https://github.com/bitcoin/bips/blob/master/bip-0133.mediawiki) + +- The P2P alert system has been removed in PR #7692 and the `alert` P2P message + is no longer supported. + +- The transaction relay mechanism used to relay one quarter of all transactions + instantly, while queueing up the rest and sending them out in batch. As + this resulted in chains of dependent transactions being reordered, it + systematically hurt transaction relay. The relay code was redesigned in PRs + \#7840 and #8082, and now always batches transactions announcements while also + sorting them according to dependency order. This significantly reduces orphan + transactions. To compensate for the removal of instant relay, the frequency of + batch sending was doubled for outgoing peers. + +- Since PR #7840 the BIP35 `mempool` command is also subject to batch processing. + Also the `mempool` message is no longer handled for non-whitelisted peers when + `NODE_BLOOM` is disabled through `-peerbloomfilters=0`. + +- The maximum size of orphan transactions that are kept in memory until their + ancestors arrive has been raised in PR #8179 from 5000 to 99999 bytes. They + are now also removed from memory when they are included in a block, conflict + with a block, and time out after 20 minutes. + +- We respond at most once to a getaddr request during the lifetime of a + connection since PR #7856. + +- Connections to peers who have recently been the first one to give us a valid + new block or transaction are protected from disconnections since PR #8084. + + +Low-level RPC changes +---------------------- + +- RPC calls have been added to output detailed statistics for individual mempool + entries, as well as to calculate the in-mempool ancestors or descendants of a + transaction: see `getmempoolentry`, `getmempoolancestors`, `getmempooldescendants`. + +- `gettxoutsetinfo` UTXO hash (`hash_serialized`) has changed. There was a divergence between + 32-bit and 64-bit platforms, and the txids were missing in the hashed data. This has been + fixed, but this means that the output will be different than from previous versions. + +- Full UTF-8 support in the RPC API. Non-ASCII characters in, for example, + wallet labels have always been malformed because they weren't taken into account + properly in JSON RPC processing. This is no longer the case. This also affects + the GUI debug console. + +- Asm script outputs replacements for OP_NOP2 and OP_NOP3 + + - OP_NOP2 has been renamed to OP_CHECKLOCKTIMEVERIFY by [BIP +65](https://github.com/bitcoin/bips/blob/master/bip-0065.mediawiki) + + - OP_NOP3 has been renamed to OP_CHECKSEQUENCEVERIFY by [BIP +112](https://github.com/bitcoin/bips/blob/master/bip-0112.mediawiki) + + - The following outputs are affected by this change: + + - RPC `getrawtransaction` (in verbose mode) + - RPC `decoderawtransaction` + - RPC `decodescript` + - REST `/rest/tx/` (JSON format) + - REST `/rest/block/` (JSON format when including extended tx details) + - `litecoin-tx -json` + +- The sorting of the output of the `getrawmempool` output has changed. + +- New RPC commands: `generatetoaddress`, `importprunedfunds`, `removeprunedfunds`, `signmessagewithprivkey`, + `getmempoolancestors`, `getmempooldescendants`, `getmempoolentry`, + `createwitnessaddress`, `addwitnessaddress`. + +- Removed RPC commands: `setgenerate`, `getgenerate`. + +- New options were added to `fundrawtransaction`: `includeWatching`, `changeAddress`, `changePosition` and `feeRate`. + + +Low-level ZMQ changes +---------------------- + +- Each ZMQ notification now contains an up-counting sequence number that allows + listeners to detect lost notifications. + The sequence number is always the last element in a multi-part ZMQ notification and + therefore backward compatible. Each message type has its own counter. + PR [#7762](https://github.com/bitcoin/bitcoin/pull/7762). + +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 Litecoin wallet + software more difficult and which seriously complicates the design of smart + contracts for Litecoin. + +- **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 Litecoin 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 litecoins they think they are spending, and by having full nodes refuse to + accept those signatures unless the amount of litecoins 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:** Litecoin addresses (both P2PKH addresses + that start with a '1' and P2SH addresses that start with a '3' or 'M') 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 Litecoin'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 Litecoin'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 Litecoin Core does not provide an option to use this capability as + of this 0.13.2 release. + +- **Script versioning:** Segwit makes it easy for future soft forks to allow + Litecoin users to individually opt-in to almost any change in the Litecoin + Script language when those users receive new transactions. Features + currently being researched by Bitcoin and Litecoin 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. At the beginning of the first retarget period after +segwit's start date of 1 January 2017 miners can update the Litecoin +client to Litecoin Core 0.13.2 to signal for segwit support. When a +super-majority of 75% is reached segwit is activated by optional, and +if 75% of blocks within a 8,064-block retarget period (about 3.5 days) +signal support for segwit, after another 8,064 blocks, segwit will +be required. + +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]. + +[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 + + +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 Litecoin 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 +---------------- + +Pre-built Linux ARM binaries have been 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: + +- `litecoin-${VERSION}-arm-linux-gnueabihf.tar.gz`: Linux binaries targeting + the 32-bit ARMv7-A architecture. +- `litecoin-${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. + + +Change to wallet handling of mempool rejection +----------------------------------------------- + +When a newly created transaction failed to enter the mempool due to +the limits on chains of unconfirmed transactions the sending RPC +calls would return an error. The transaction would still be queued +in the wallet and, once some of the parent transactions were +confirmed, broadcast after the software was restarted. + +This behavior has been changed to return success and to reattempt +mempool insertion at the same time transaction rebroadcast is +attempted, avoiding a need for a restart. + +Transactions in the wallet which cannot be accepted into the mempool +can be abandoned with the previously existing abandontransaction RPC +(or in the GUI via a context menu on the transaction). + +Credits +======= + +Thanks to everyone who directly contributed to this release: + +- [The Bitcoin Core Developers](/doc/release-notes) +- Charles Lee +- Adrian Gallagher +- shaolinfry +- Xinxi Wang +- Xinrong Guo +- Fan Yang +- Peng Sun +- Loshan T diff --git a/doc/release-notes-litecoin.md b/doc/release-notes-litecoin.md new file mode 100644 index 0000000000..5d7b21c784 --- /dev/null +++ b/doc/release-notes-litecoin.md @@ -0,0 +1,48 @@ +Litecoin Core version 0.14.0 is now available from: + + + +This is a new major version release, including new features, various bugfixes and performance improvements, as well as updated translations. +It is recommended to upgrade to this version. + +Please report bugs using the issue tracker at github: + + + +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 litecoin +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 +=============== + +Credits +======= + +Thanks to everyone who directly contributed to this release: + +- [The Bitcoin Core Developers](/doc/release-notes) +- Adrian Gallagher +- shaolinfry