If you are running an older version, shut it down. Wait until it has completely
shut down (which might take a few minutes in some cases), then run the
installer (on Windows) or just copy over `/Applications/Bitcoin-Qt` (on macOS)
or `bitcoind`/`bitcoin-qt` (on Linux).
Upgrading directly from a version of Bitcoin Core that has reached its EOL is
possible, but it might take some time if the data directory needs to be migrated. Old
wallet versions of Bitcoin Core are generally supported.
Compatibility
==============
Bitcoin Core is supported and extensively tested on operating systems
using the Linux kernel, macOS 11.0+, and Windows 7 and newer. Bitcoin
Core should also work on most other Unix-like systems but is not as
frequently tested on them. It is not recommended to use Bitcoin Core on
unsupported systems.
Notable changes
===============
P2P and network changes
-----------------------
- Experimental support for the v2 transport protocol defined in
[BIP324](https://github.com/bitcoin/bips/blob/master/bip-0324.mediawiki) was added.
It is off by default, but when enabled using `-v2transport` it will be negotiated
on a per-connection basis with other peers that support it too. The existing
v1 transport protocol remains fully supported.
- Nodes with multiple reachable networks will actively try to have at least one
outbound connection to each network. This improves individual resistance to
eclipse attacks and network level resistance to partition attacks. Users no
longer need to perform active measures to ensure being connected to multiple
enabled networks. (#27213)
Pruning
-------
- When using assumeutxo with `-prune`, the prune budget may be exceeded if it is set
lower than 1100MB (i.e. `MIN_DISK_SPACE_FOR_BLOCK_FILES * 2`). Prune budget is normally
split evenly across each chainstate, unless the resulting prune budget per chainstate
is beneath `MIN_DISK_SPACE_FOR_BLOCK_FILES` in which case that value will be used. (#27596)
Updated RPCs
------------
- Setting `-rpcserialversion=0` is deprecated and will be removed in
a future release. It can currently still be used by also adding
the `-deprecatedrpc=serialversion` option. (#28448)
- The `hash_serialized_2` value has been removed from `gettxoutsetinfo` since the value it
calculated contained a bug and did not take all data into account. It is superseded by
`hash_serialized_3` which provides the same functionality but serves the correctly calculated hash. (#28685)
- New fields `transport_protocol_type` and `session_id` were added to the `getpeerinfo` RPC to indicate
whether the v2 transport protocol is in use, and if so, what the session id is.
- A new argument `v2transport` was added to the `addnode` RPC to indicate whether a v2 transaction connection
is to be attempted with the peer.
- [Miniscript](https://bitcoin.sipa.be/miniscript/) expressions can now be used in Taproot descriptors for all RPCs working with descriptors. (#27255)
-`finalizepsbt` is now able to finalize a PSBT with inputs spending [Miniscript](https://bitcoin.sipa.be/miniscript/)-compatible Taproot leaves. (#27255)
Changes to wallet related RPCs can be found in the Wallet section below.
New RPCs
--------
-`loadtxoutset` has been added, which allows loading a UTXO snapshot of the format
generated by `dumptxoutset`. Once this snapshot is loaded, its contents will be
deserialized into a second chainstate data structure, which is then used to sync to
the network's tip.
Meanwhile, the original chainstate will complete the initial block download process in
the background, eventually validating up to the block that the snapshot is based upon.
The result is a usable bitcoind instance that is current with the network tip in a
matter of minutes rather than hours. UTXO snapshot are typically obtained via
third-party sources (HTTP, torrent, etc.) which is reasonable since their contents
are always checked by hash.
You can find more information on this process in the `assumeutxo` design
`getchainstates` has been added to aid in monitoring the assumeutxo sync process.
- A new `getprioritisedtransactions` RPC has been added. It returns a map of all fee deltas created by the
user with prioritisetransaction, indexed by txid. The map also indicates whether each transaction is
present in the mempool. (#27501)
- A new RPC, `submitpackage`, has been added. It can be used to submit a list of raw hex
transactions to the mempool to be evaluated as a package using consensus and mempool policy rules.
These policies include package CPFP, allowing a child with high fees to bump a parent below the
mempool minimum feerate (but not minimum relay feerate). (#27609)
- Warning: successful submission does not mean the transactions will propagate throughout the
network, as package relay is not supported.
- Not all features are available. The package is limited to a child with all of its
unconfirmed parents, and no parent may spend the output of another parent. Also, package
RBF is not supported. Refer to doc/policy/packages.md for more details on package policies
and limitations.
- This RPC is experimental. Its interface may change.
- A new RPC `getaddrmaninfo` has been added to view the distribution of addresses in the new and tried table of the
node's address manager across different networks(ipv4, ipv6, onion, i2p, cjdns). The RPC returns count of addresses
in new and tried table as well as their sum for all networks. (#27511)
- A new `importmempool` RPC has been added. It loads a valid `mempool.dat` file and attempts to
add its contents to the mempool. This can be useful to import mempool data from another node
without having to modify the datadir contents and without having to restart the node. (#27460)
- Warning: Importing untrusted files is dangerous, especially if metadata from the file is taken over.
- If you want to apply fee deltas, it is recommended to use the `getprioritisedtransactions` and
`prioritisetransaction` RPCs instead of the `apply_fee_delta_priority` option to avoid
double-prioritising any already-prioritised transactions in the mempool.
Updated settings
----------------
-`bitcoind` and `bitcoin-qt` will now raise an error on startup
if a datadir that is being used contains a bitcoin.conf file that
will be ignored, which can happen when a datadir= line is used in
a bitcoin.conf file. The error message is just a diagnostic intended
to prevent accidental misconfiguration, and it can be disabled to
restore the previous behavior of using the datadir while ignoring
the bitcoin.conf contained in it. (#27302)
- Passing an invalid `-debug`, `-debugexclude`, or `-loglevel` logging configuration
option now raises an error, rather than logging an easily missed warning. (#27632)
Changes to GUI or wallet related settings can be found in the GUI or Wallet section below.
New settings
------------
Tools and Utilities
-------------------
- A new `bitcoinconsensus_verify_script_with_spent_outputs` function is available in libconsensus which optionally accepts the spent outputs of the transaction being verified.
- A new `bitcoinconsensus_SCRIPT_FLAGS_VERIFY_TAPROOT` flag is available in libconsensus that will verify scripts with the Taproot spending rules.
Wallet
------
- Wallet loading has changed in this release. Wallets with some corrupted records that could be
previously loaded (with warnings) may no longer load. For example, wallets with corrupted
address book entries may no longer load. If this happens, it is recommended
load the wallet in a previous version of Bitcoin Core and import the data into a new wallet.
Please also report an issue to help improve the software and make wallet loading more robust
- The `gettransaction`, `listtransactions`, `listsinceblock` RPCs now return
the `abandoned` field for all transactions. Previously, the "abandoned" field
was only returned for sent transactions. (#25158)
- The `listdescriptors`, `decodepsbt` and similar RPC methods now show `h` rather than apostrophe (`'`) to indicate
hardened derivation. This does not apply when using the `private` parameter, which
matches the marker used when descriptor was generated or imported. Newly created
wallets use `h`. This change makes it easier to handle descriptor strings manually.
E.g. the `importdescriptors` RPC call is easiest to use `h` as the marker: `'["desc": ".../0h/..."]'`.
With this change `listdescriptors` will use `h`, so you can copy-paste the result,
without having to add escape characters or switch `'` to 'h' manually.
Note that this changes the descriptor checksum.
For legacy wallets the `hdkeypath` field in `getaddressinfo` is unchanged,
nor is the serialization format of wallet dumps. (#26076)
- The `getbalances` RPC now returns a `lastprocessedblock` JSON object which contains the wallet's last processed block
hash and height at the time the balances were calculated. This result shouldn't be cached because importing new keys could invalidate it. (#26094)
- The `gettransaction` RPC now returns a `lastprocessedblock` JSON object which contains the wallet's last processed block
hash and height at the time the transaction information was generated. (#26094)
- The `getwalletinfo` RPC now returns a `lastprocessedblock` JSON object which contains the wallet's last processed block
hash and height at the time the wallet information was generated. (#26094)
- Coin selection and transaction building now accounts for unconfirmed low-feerate ancestor transactions. When it is necessary to spend unconfirmed outputs, the wallet will add fees to ensure that the new transaction with its ancestors will achieve a mining score equal to the feerate requested by the user. (#26152)
- For RPC methods which accept `options` parameters ((`importmulti`, `listunspent`,
- The transaction list in the GUI no longer provides a special category for "payment to yourself". Now transactions that have both inputs and outputs that affect the wallet are displayed on separate lines for spending and receiving. (gui#119)
- A new menu option allows migrating a legacy wallet based on keys and implied output script types stored in BerkeleyDB (BDB) to a modern wallet that uses descriptors stored in SQLite. (gui#738)
- The PSBT operations dialog marks outputs paying your own wallet with "own address". (gui#740)
- The ability to create legacy wallets is being removed. (gui#764)
