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10.21.0 Release Notes
2====================
3
4Bitcoin Core version 0.21.0 is now available from:
5
6  <https://bitcoincore.org/bin/bitcoin-core-0.21.0/>
7
8This release includes new features, various bug fixes and performance
9improvements, as well as updated translations.
10
11Please report bugs using the issue tracker at GitHub:
12
13  <https://github.com/bitcoin/bitcoin/issues>
14
15To receive security and update notifications, please subscribe to:
16
17  <https://bitcoincore.org/en/list/announcements/join/>
18
19How to Upgrade
20==============
21
22If you are running an older version, shut it down. Wait until it has completely
23shut down (which might take a few minutes in some cases), then run the
24installer (on Windows) or just copy over `/Applications/Bitcoin-Qt` (on Mac)
25or `bitcoind`/`bitcoin-qt` (on Linux).
26
27Upgrading directly from a version of Bitcoin Core that has reached its EOL is
28possible, but it might take some time if the data directory needs to be migrated. Old
29wallet versions of Bitcoin Core are generally supported.
30
31Compatibility
32==============
33
34Bitcoin Core is supported and extensively tested on operating systems
35using the Linux kernel, macOS 10.12+, and Windows 7 and newer.  Bitcoin
36Core should also work on most other Unix-like systems but is not as
37frequently tested on them.  It is not recommended to use Bitcoin Core on
38unsupported systems.
39
40From Bitcoin Core 0.20.0 onwards, macOS versions earlier than 10.12 are no
41longer supported. Additionally, Bitcoin Core does not yet change appearance
42when macOS "dark mode" is activated.
43
44The node's known peers are persisted to disk in a file called `peers.dat`. The
45format of this file has been changed in a backwards-incompatible way in order to
46accommodate the storage of Tor v3 and other BIP155 addresses. This means that if
47the file is modified by 0.21.0 or newer then older versions will not be able to
48read it. Those old versions, in the event of a downgrade, will log an error
49message "Incorrect keysize in addrman deserialization" and will continue normal
50operation as if the file was missing, creating a new empty one. (#19954, #20284)
51
52Notable changes
53===============
54
55P2P and network changes
56-----------------------
57
58- The mempool now tracks whether transactions submitted via the wallet or RPCs
59  have been successfully broadcast. Every 10-15 minutes, the node will try to
60  announce unbroadcast transactions until a peer requests it via a `getdata`
61  message or the transaction is removed from the mempool for other reasons.
62  The node will not track the broadcast status of transactions submitted to the
63  node using P2P relay. This version reduces the initial broadcast guarantees
64  for wallet transactions submitted via P2P to a node running the wallet. (#18038)
65
66- The size of the set of transactions that peers have announced and we consider
67  for requests has been reduced from 100000 to 5000 (per peer), and further
68  announcements will be ignored when that limit is reached. If you need to dump
69  (very) large batches of transactions, exceptions can be made for trusted
70  peers using the "relay" network permission. For localhost for example it can
71  be enabled using the command line option `-whitelist=relay@127.0.0.1`.
72  (#19988)
73
74- This release adds support for Tor version 3 hidden services, and rumoring them
75  over the network to other peers using
76  [BIP155](https://github.com/bitcoin/bips/blob/master/bip-0155.mediawiki).
77  Version 2 hidden services are still fully supported by Bitcoin Core, but the
78  Tor network will start
79  [deprecating](https://blog.torproject.org/v2-deprecation-timeline) them in the
80  coming months. (#19954)
81
82- The Tor onion service that is automatically created by setting the
83  `-listenonion` configuration parameter will now be created as a Tor v3 service
84  instead of Tor v2. The private key that was used for Tor v2 (if any) will be
85  left untouched in the `onion_private_key` file in the data directory (see
86  `-datadir`) and can be removed if not needed. Bitcoin Core will no longer
87  attempt to read it. The private key for the Tor v3 service will be saved in a
88  file named `onion_v3_private_key`. To use the deprecated Tor v2 service (not
89  recommended), the `onion_private_key` can be copied over
90  `onion_v3_private_key`, e.g.
91  `cp -f onion_private_key onion_v3_private_key`. (#19954)
92
93- The client writes a file (`anchors.dat`) at shutdown with the network addresses
94  of the node’s two outbound block-relay-only peers (so called "anchors"). The
95  next time the node starts, it reads this file and attempts to reconnect to those
96  same two peers. This prevents an attacker from using node restarts to trigger a
97  complete change in peers, which would be something they could use as part of an
98  eclipse attack. (#17428)
99
100- This release adds support for serving
101  [BIP157](https://github.com/bitcoin/bips/blob/master/bip-0157.mediawiki) compact
102  filters to peers on the network when enabled using
103  `-blockfilterindex=1 -peerblockfilters=1`. (#16442)
104
105- This release adds support for signets
106  ([BIP325](https://github.com/bitcoin/bips/blob/master/bip-0325.mediawiki)) in
107  addition to the existing mainnet, testnet, and regtest networks. Signets are
108  centrally-controlled test networks, allowing them to be more predictable
109  test environments than the older testnet. One public signet is maintained, and
110  selectable using `-signet`. It is also possible to create personal signets.
111  (#18267).
112
113- This release implements
114  [BIP339](https://github.com/bitcoin/bips/blob/master/bip-0339.mediawiki)
115  wtxid relay. When negotiated, transactions are announced using their wtxid
116  instead of their txid. (#18044).
117
118- This release implements the proposed Taproot consensus rules
119  ([BIP341](https://github.com/bitcoin/bips/blob/master/bip-0341.mediawiki) and
120  [BIP342](https://github.com/bitcoin/bips/blob/master/bip-0342.mediawiki)),
121  without activation on mainnet. Experimentation with Taproot can be done on
122  signet, where its rules are already active. (#19553)
123
124Updated RPCs
125------------
126
127- The `getpeerinfo` RPC has a new `network` field that provides the type of
128  network ("ipv4", "ipv6", or "onion") that the peer connected through. (#20002)
129
130- The `getpeerinfo` RPC now has additional `last_block` and `last_transaction`
131  fields that return the UNIX epoch time of the last block and the last *valid*
132  transaction received from each peer. (#19731)
133
134- `getnetworkinfo` now returns two new fields, `connections_in` and
135  `connections_out`, that provide the number of inbound and outbound peer
136  connections. These new fields are in addition to the existing `connections`
137  field, which returns the total number of peer connections. (#19405)
138
139- Exposed transaction version numbers are now treated as unsigned 32-bit
140  integers instead of signed 32-bit integers. This matches their treatment in
141  consensus logic. Versions greater than 2 continue to be non-standard
142  (matching previous behavior of smaller than 1 or greater than 2 being
143  non-standard). Note that this includes the `joinpsbt` command, which combines
144  partially-signed transactions by selecting the highest version number.
145  (#16525)
146
147- `getmempoolinfo` now returns an additional `unbroadcastcount` field. The
148  mempool tracks locally submitted transactions until their initial broadcast
149  is acknowledged by a peer. This field returns the count of transactions
150  waiting for acknowledgement.
151
152- Mempool RPCs such as `getmempoolentry` and `getrawmempool` with
153  `verbose=true` now return an additional `unbroadcast` field. This indicates
154  whether initial broadcast of the transaction has been acknowledged by a
155  peer. `getmempoolancestors` and `getmempooldescendants` are also updated.
156
157- The `getpeerinfo` RPC no longer returns the `banscore` field unless the configuration
158  option `-deprecatedrpc=banscore` is used. The `banscore` field will be fully
159  removed in the next major release. (#19469)
160
161- The `testmempoolaccept` RPC returns `vsize` and a `fees` object with the `base` fee
162  if the transaction would pass validation. (#19940)
163
164- The `getpeerinfo` RPC now returns a `connection_type` field. This indicates
165  the type of connection established with the peer. It will return one of six
166  options. For more information, see the `getpeerinfo` help documentation.
167  (#19725)
168
169- The `getpeerinfo` RPC no longer returns the `addnode` field by default. This
170  field will be fully removed in the next major release.  It can be accessed
171  with the configuration option `-deprecatedrpc=getpeerinfo_addnode`. However,
172  it is recommended to instead use the `connection_type` field (it will return
173  `manual` when addnode is true). (#19725)
174
175- The `getpeerinfo` RPC no longer returns the `whitelisted` field by default. 
176  This field will be fully removed in the next major release. It can be accessed 
177  with the configuration option `-deprecatedrpc=getpeerinfo_whitelisted`. However, 
178  it is recommended to instead use the `permissions` field to understand if specific 
179  privileges have been granted to the peer. (#19770)
180
181- The `walletcreatefundedpsbt` RPC call will now fail with
182  `Insufficient funds` when inputs are manually selected but are not enough to cover
183  the outputs and fee. Additional inputs can automatically be added through the
184  new `add_inputs` option. (#16377)
185
186- The `fundrawtransaction` RPC now supports `add_inputs` option that when `false`
187  prevents adding more inputs if necessary and consequently the RPC fails.
188
189Changes to Wallet or GUI related RPCs can be found in the GUI or Wallet section below.
190
191New RPCs
192--------
193
194- The `getindexinfo` RPC returns the actively running indices of the node,
195  including their current sync status and height. It also accepts an `index_name`
196  to specify returning the status of that index only. (#19550)
197
198Build System
199------------
200
201Updated settings
202----------------
203
204- The same ZeroMQ notification (e.g. `-zmqpubhashtx=address`) can now be
205  specified multiple times to publish the same notification to different ZeroMQ
206  sockets. (#18309)
207
208- The `-banscore` configuration option, which modified the default threshold for
209  disconnecting and discouraging misbehaving peers, has been removed as part of
210  changes in 0.20.1 and in this release to the handling of misbehaving peers.
211  Refer to "Changes regarding misbehaving peers" in the 0.20.1 release notes for
212  details. (#19464)
213
214- The `-debug=db` logging category, which was deprecated in 0.20 and replaced by
215  `-debug=walletdb` to distinguish it from `coindb`, has been removed. (#19202)
216
217- A `download` permission has been extracted from the `noban` permission. For
218  compatibility, `noban` implies the `download` permission, but this may change
219  in future releases. Refer to the help of the affected settings `-whitebind`
220  and `-whitelist` for more details. (#19191)
221
222- Netmasks that contain 1-bits after 0-bits (the 1-bits are not contiguous on
223  the left side, e.g. 255.0.255.255) are no longer accepted. They are invalid
224  according to RFC 4632. Netmasks are used in the `-rpcallowip` and `-whitelist`
225  configuration options and in the `setban` RPC. (#19628)
226
227- The `-blocksonly` setting now completely disables fee estimation. (#18766)
228
229Changes to Wallet or GUI related settings can be found in the GUI or Wallet section below.
230
231Tools and Utilities
232-------------------
233
234- A new `bitcoin-cli -netinfo` command provides a network peer connections
235  dashboard that displays data from the `getpeerinfo` and `getnetworkinfo` RPCs
236  in a human-readable format. An optional integer argument from `0` to `4` may
237  be passed to see increasing levels of detail. (#19643)
238
239- A new `bitcoin-cli -generate` command, equivalent to RPC `generatenewaddress`
240  followed by `generatetoaddress`, can generate blocks for command line testing
241  purposes. This is a client-side version of the former `generate` RPC. See the
242  help for details. (#19133)
243
244- The `bitcoin-cli -getinfo` command now displays the wallet name and balance for
245  each of the loaded wallets when more than one is loaded (e.g. in multiwallet
246  mode) and a wallet is not specified with `-rpcwallet`. (#18594)
247
248- The `connections` field of `bitcoin-cli -getinfo` is now expanded to return a JSON
249  object with `in`, `out` and `total` numbers of peer connections. It previously
250  returned a single integer value for the total number of peer connections. (#19405)

src/wallet/receive.cpp

src/wallet/coinselection.cpp

src/consensus/validation.h

src/primitives/transaction.cpp

src/script/descriptor.cpp

src/bitcoin-cli.cpp

src/rpc/blockchain.cpp

src/rpc/rawtransaction.cpp

src/init.cpp

src/crypto/sha256.cpp

src/consensus/merkle.h

src/consensus/tx_check.h

src/consensus/tx_verify.h

src/policy/feerate.h

src/policy/feerate.cpp

src/primitives/transaction_identifier.h

src/chainparamsbase.h

src/chainparamsbase.cpp

src/util/moneystr.cpp

src/crypto/ripemd160.h

src/crypto/sha1.h

src/crypto/sha512.h

src/crypto/hmac_sha256.h

src/crypto/hmac_sha512.h

src/crypto/hmac_sha256.cpp

src/crypto/hmac_sha512.cpp

src/crypto/hkdf_sha256_32.h

src/crypto/hkdf_sha256_32.cpp

src/support/cleanse.h

src/support/cleanse.cpp

src/crypto/siphash.cpp

src/crypto/muhash.h

src/crypto/chacha20.h

src/crypto/poly1305.h

src/crypto/chacha20poly1305.h

src/crypto/chacha20poly1305.cpp

src/util/chaintype.cpp

src/util/obfuscation.h

src/util/byte_units.h

src/util/overflow.h

src/blockencodings.cpp

src/net_permissions.cpp

src/policy/packages.cpp

src/policy/rbf.cpp

src/policy/truc_policy.cpp

src/policy/ephemeral_policy.cpp

src/policy/settings.cpp

src/policy/policy.cpp

src/node/transaction.cpp

src/node/coin.cpp

src/rpc/client.cpp

src/rpc/external_signer.cpp

src/rpc/request.cpp

src/rpc/server_util.cpp

src/rpc/fees.cpp

src/rpc/output_script.cpp

src/rpc/rawtransaction_util.cpp

src/rpc/rawtransaction_util.h

src/rpc/register.h

src/rpc/request.h

src/rpc/server_util.h

src/rpc/protocol.h

src/rpc/server.h

src/rpc/signmessage.cpp

src/rpc/txoutproof.cpp

src/rpc/util.cpp

src/rpc/util.h

src/wallet/rpc/addresses.cpp

src/wallet/rpc/backup.cpp

src/wallet/rpc/coins.cpp

src/wallet/rpc/encrypt.cpp

src/wallet/rpc/signmessage.cpp

src/wallet/rpc/util.cpp

src/wallet/rpc/util.h

src/wallet/coincontrol.cpp

src/wallet/coincontrol.h

src/wallet/context.cpp

src/wallet/context.h

src/wallet/crypter.cpp

src/wallet/crypter.h

src/wallet/db.cpp

src/wallet/export.cpp

src/wallet/external_signer_scriptpubkeyman.cpp

src/wallet/rpc/spend.cpp

src/wallet/rpc/transactions.cpp

src/wallet/rpc/wallet.cpp

src/wallet/feebumper.cpp

src/wallet/feebumper.h

src/index/base.h

src/index/base.cpp

src/index/txindex.h

src/index/txindex.cpp

src/index/txindex_key.h

src/index/txospenderindex.h

src/index/txospenderindex.cpp

src/index/blockfilterindex.h

src/index/blockfilterindex.cpp

src/index/coinstatsindex.h

src/index/coinstatsindex.cpp

src/index/db_key.h

src/index/disktxpos.h

src/kernel/chain.cpp

src/kernel/chain.h

src/kernel/checks.cpp

src/kernel/checks.h

src/kernel/context.cpp

src/kernel/context.h

src/kernel/cs_main.cpp

src/kernel/cs_main.h

src/kernel/disconnected_transactions.cpp

src/kernel/disconnected_transactions.h

src/kernel/mempool_removal_reason.cpp

src/kernel/mempool_removal_reason.h

src/kernel/coinstats.cpp

src/kernel/coinstats.h

src/kernel/chainparams.cpp

src/kernel/chainparams.h

src/wallet/sqlite.cpp

src/wallet/sqlite.h

src/wallet/transaction.cpp

src/wallet/transaction.h

src/wallet/dump.cpp

src/wallet/dump.h

src/wallet/init.cpp

src/wallet/walletutil.cpp

src/wallet/walletutil.h

src/wallet/wallettool.cpp

src/wallet/wallettool.h

src/wallet/export.h

src/wallet/migrate.cpp

src/wallet/migrate.h

src/wallet/db.h

src/wallet/walletdb.cpp

src/wallet/interfaces.cpp

src/wallet/scriptpubkeyman.cpp

src/wallet/scriptpubkeyman.h

src/kernel/bitcoinkernel.cpp

src/kernel/bitcoinkernel.h

src/kernel/bitcoinkernel_wrapper.h

src/node/chainstate.cpp

src/node/chainstate.h

src/node/blockstorage.cpp

src/node/blockstorage.h

src/node/mempool_persist.cpp

src/node/mempool_persist.h

src/node/utxo_snapshot.cpp

src/node/utxo_snapshot.h

src/node/kernel_notifications.cpp

src/node/kernel_notifications.h

src/node/blockmanager_args.cpp

src/kernel/blockmanager_opts.h

src/util/expected.cpp

src/policy/settings.h

src/util/types.h

src/kernel/messagestartchars.h

src/kernel/warning.h

src/util/exception.h

src/common/license_info.h

src/node/coins_view_args.h

src/node/database_args.h

src/util/batchpriority.h

src/util/ui_change_type.h

src/node/coins_view_args.cpp

src/node/peerman_args.h

src/util/serfloat.h

src/node/blockmanager_args.h

src/node/database_args.cpp

src/util/overloaded.h

src/interfaces/types.h

src/node/chainstatemanager_args.h

src/node/minisketchwrapper.h

src/util/macros.h

src/util/syserror.h

src/common/run_command.h

src/util/bytevectorhash.cpp

src/node/mempool_persist_args.cpp

src/util/exec.h

src/util/rbf.h

src/crypto/hex_base.h

src/node/mempool_persist_args.h

src/interfaces/echo.h

src/util/any.h

src/util/batchpriority.cpp

src/util/threadnames.h

src/node/coin.h

src/node/mempool_args.h

src/util/asmap.h

src/util/bytevectorhash.h

src/node/context.cpp

src/util/insert.h

src/util/readwritefile.h

src/node/peerman_args.cpp

src/node/interface_ui.cpp

src/interfaces/handler.h

src/node/mining_args.h

src/util/hasher.cpp

src/common/init.h

src/kernel/mempool_limits.h

src/common/system.h

src/crypto/sha3.h

src/util/threadinterrupt.cpp

src/node/protocol_version.h

src/util/exception.cpp

src/common/messages.h

src/node/connection_types.cpp

src/util/bip32.h

src/common/license_info.cpp

src/util/stdmutex.h

src/common/run_command.cpp

src/util/check.cpp

src/util/golombrice.h

src/node/types.h

src/node/timeoffsets.h

src/util/readwritefile.cpp

src/util/fastrange.h

src/util/signalinterrupt.h

src/util/task_runner.h

src/util/syserror.cpp

src/common/interfaces.cpp

src/common/types.h

src/util/threadinterrupt.h

src/kernel/chainstatemanager_opts.h

src/node/psbt.h

src/policy/ephemeral_policy.h

src/util/trace.h

src/common/url.cpp

src/kernel/mempool_options.h

src/util/serfloat.cpp

src/kernel/notifications_interface.h

src/node/timeoffsets.cpp

src/node/warnings.cpp

src/util/hash_type.h

src/crypto/hex_base.cpp

src/node/eviction.h

src/util/tokenbucket.h

src/crypto/aes.h

src/common/pcp.h

src/util/feefrac.cpp

src/node/transaction.h

src/util/threadnames.cpp

src/common/signmessage.h

src/util/exec.cpp

src/util/signalinterrupt.cpp

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