bitcoin/doc/release-notes.md

(note: this is a temporary file, to be added-to by anybody, and moved to release-notes at release time)

Bitcoin Core version version is now available from:

https://bitcoincore.org/bin/bitcoin-core-*version*/

This is a new major version release, including new features, various bugfixes and performance improvements, as well as updated translations.

Please report bugs using the issue tracker at GitHub:

https://github.com/bitcoin/bitcoin/issues

To receive security and update notifications, please subscribe to:

https://bitcoincore.org/en/list/announcements/join/

How to Upgrade

If you are running an older version, shut it down. Wait until it has completely shut down (which might take a few minutes for older versions), then run the installer (on Windows) or just copy over /Applications/Bitcoin-Qt (on Mac) or bitcoind/bitcoin-qt (on Linux).

The first time you run version 0.15.0, your chainstate database will be converted to a new format, which will take anywhere from a few minutes to half an hour, depending on the speed of your machine.

Note that the block database format also changed in version 0.8.0 and there is no automatic upgrade code from before version 0.8 to version 0.15.0. Upgrading directly from 0.7.x and earlier without redownloading the blockchain is not supported. However, as usual, old wallet versions are still supported.

Downgrading warning

The chainstate database for this release is not compatible with previous releases, so if you run 0.15 and then decide to switch back to any older version, you will need to run the old release with the -reindex-chainstate option to rebuild the chainstate data structures in the old format.

If your node has pruning enabled, this will entail re-downloading and processing the entire blockchain.

Compatibility

Bitcoin Core is extensively tested on multiple operating systems using the Linux kernel, macOS 10.8+, and Windows 7 and newer (Windows XP is not supported).

Bitcoin Core should also work on most other Unix-like systems but is not frequently tested on them.

Notable changes

GUI changes

• Block storage can be limited under Preferences, in the Main tab. Undoing this setting requires downloading the full blockchain again. This mode is incompatible with -txindex and -rescan.

RPC changes

Low-level changes

• The createrawtransaction RPC will now accept an array or dictionary (kept for compatibility) for the outputs parameter. This means the order of transaction outputs can be specified by the client.
• The fundrawtransaction RPC will reject the previously deprecated reserveChangeKey option.
• sendmany now shuffles outputs to improve privacy, so any previously expected behavior with regards to output ordering can no longer be relied upon.
• The new RPC testmempoolaccept can be used to test acceptance of a transaction to the mempool without adding it.
• JSON transaction decomposition now includes a weight field which provides the transaction's exact weight. This is included in REST /rest/tx/ and /rest/block/ endpoints when in json mode. This is also included in getblock (with verbosity=2), listsinceblock, listtransactions, and getrawtransaction RPC commands.
• New fees field introduced in getrawmempool, getmempoolancestors, getmempooldescendants and getmempoolentry when verbosity is set to true with sub-fields ancestor, base, modified and descendant denominated in BTC. This new field deprecates previous fee fields, such as fee, modifiedfee, ancestorfee and descendantfee.
• The new RPC getzmqnotifications returns information about active ZMQ notifications.

External wallet files

The -wallet=<path> option now accepts full paths instead of requiring wallets to be located in the -walletdir directory.

Newly created wallet format

If -wallet=<path> is specified with a path that does not exist, it will now create a wallet directory at the specified location (containing a wallet.dat data file, a db.log file, and database/log.?????????? files) instead of just creating a data file at the path and storing log files in the parent directory. This should make backing up wallets more straightforward than before because the specified wallet path can just be directly archived without having to look in the parent directory for transaction log files.

For backwards compatibility, wallet paths that are names of existing data files in the -walletdir directory will continue to be accepted and interpreted the same as before.

Low-level RPC changes

• When bitcoin is not started with any -wallet=<path> options, the name of the default wallet returned by getwalletinfo and listwallets RPCs is now the empty string "" instead of "wallet.dat". If bitcoin is started with any -wallet=<path> options, there is no change in behavior, and the name of any wallet is just its <path> string.

• Passing an empty string ("") as the address_type parameter to getnewaddress, getrawchangeaddress, addmultisigaddress, fundrawtransaction RPCs is now an error. Previously, this would fall back to using the default address type. It is still possible to pass null or leave the parameter unset to use the default address type.

• Bare multisig outputs to our keys are no longer automatically treated as incoming payments. As this feature was only available for multisig outputs for which you had all private keys in your wallet, there was generally no use for them compared to single-key schemes. Furthermore, no address format for such outputs is defined, and wallet software can't easily send to it. These outputs will no longer show up in listtransactions, listunspent, or contribute to your balance, unless they are explicitly watched (using importaddress or importmulti with hex script argument). signrawtransaction* also still works for them.

Logging

• The log timestamp format is now ISO 8601 (e.g. "2018-02-28T12:34:56Z").

• When running bitcoind with -debug but without -daemon, logging to stdout is now the default behavior. Setting -printtoconsole=1 no longer implicitly disables logging to debug.log. Instead, logging to file can be explicitly disabled by setting -debuglogfile=0.

Miner block size removed

The -blockmaxsize option for miners to limit their blocks' sizes was deprecated in V0.15.1, and has now been removed. Miners should use the -blockmaxweight option if they want to limit the weight of their blocks' weights.

Python Support

Support for Python 2 has been discontinued for all test files and tools.

Credits

Thanks to everyone who directly contributed to this release:

As well as everyone that helped translating on Transifex.