27.1.0

Release Notes for Bitcoin Cash Node version 27.1.0

Bitcoin Cash Node version 27.1.0 is now available from:

https://bitcoincashnode.org

Overview

This release of Bitcoin Cash Node (BCHN) includes some bug fixes and important reliability enhancements.

Usage recommendations

Users who are running v27.0.0 or earlier are encouraged to upgrade to v27.1.0 as it includes some bugfixes as well as
updated checkpoints for the recently completed (15 May 2024) network upgrade. It also include some performance and
reliability fixes related to transaction processing.

Network changes

The internal transaction processing logic for both regular and orphan transactions has been reworked to be more
performant and more reliable.

Added functionality

None.

Deprecated functionality

None.

Modified functionality

The command-line option -upgrade10activationtime has been renamed to -upgrade10activationheight and is now height-based,
rather than MTP time-based. The next upgrade is still expected to be MTP time-based.

Removed functionality

BIP70 payment request support has been removed from the Qt-based GUI. The
reason for this is that BIP70 payment requests have historically suffered
from a number of security flaws and maintainence of this feature poses a
risk to full node software. Users wishing to use a GUI wallet that supports
BIP70 are recommended to use one of the many light wallets such as Electron
Cash or Bitcoin.com that continue to support BIP70 payment requests.

New RPC methods

None.

User interface changes

• The -wipeignore bitcoin-seeder command line option has been removed. The way the
  list of ignored nodes is handled has been broken for many years. Rather than ignoring
  nodes until a particular time, nodes were being ignored from that time. This meant
  that ignored nodes that ever reached this timeout would stay ignored forever; and
  until that point, they would be processed as often as any other node rather than
  being ignored for a cooling-off period as intended. To resolve this, we decided to
  simply remove this facility entirely, meaning that nodes will now never be ignored.
• The datadir= conf file variable appearing both outside and inside a section header in
  the conf file works as expected now, and no longer leads to unexpected blocksdir=
  settings (!1816).

Regressions

Bitcoin Cash Node 27.1.0 does not introduce any known regressions as compared to 27.0.0.

Limitations

The following are limitations in this release of which users should be aware:

1. CashToken support is low-level at this stage. The wallet application does
   not yet keep track of the user's tokens.
   Tokens are only manageable via RPC commands currently.
   They only persist through the UTXO database and block database at this
   point.
   There are existing RPC commands to list and filter for tokens in the UTXO set.
   RPC raw transaction handling commands have been extended to allow creation
   (and sending) of token transactions.
   Interested users are advised to consult the functional test in
   test/functional/bchn-rpc-tokens.py for examples on token transaction
   construction and listing.
   Future releases will aim to extend the RPC API with more convenient
   ways to create and spend tokens, as well as upgrading the wallet storage
   and indexing subsystems to persistently store data about tokens of interest
   to the user. Later we expect to add GUI wallet management of Cash Tokens.

2. Transactions with SIGHASH_UTXO are not covered by DSProofs at present.

3. P2SH-32 is not used by default in the wallet (regular P2SH-20 remains
   the default wherever P2SH is treated).

4. The markup of Double Spend Proof events in the wallet does not survive
   a restart of the wallet, as the information is not persisted to the
   wallet.

5. The ABLA algorithm for BCH is currently temporarily set to cap the max block
   size at 2GB. This is due to limitations in the p2p protocol (as well as the
   block data file format in BCHN).

Known Issues

Some issues could not be closed in time for release, but we are tracking all
of them on our GitLab repository.

• The minimum macOS version is 10.14 (Mojave).
  Earlier macOS versions are no longer supported.

• Windows users are recommended not to run multiple instances of bitcoin-qt
  or bitcoind on the same machine if the wallet feature is enabled.
  There is risk of data corruption if instances are configured to use the same
  wallet folder.

• Some users have encountered unit tests failures when running in WSL
  environments (e.g. WSL/Ubuntu). At this time, WSL is not considered a
  supported environment for the software. This may change in future.
  It has been reported that using WSL2 improves the issue.

• doc/dependencies.md needs revision (Issue).

• For users running from sources built with BerkeleyDB releases newer than
  the 5.3 which is used in this release, please take into consideration
  the database format compatibility issues described in Issue.
  When building from source it is recommended to use BerkeleyDB 5.3 as this
  avoids wallet database incompatibility issues with the official release.

• The test_bitcoin-qt test executable fails on Linux Mint 20
  (see Issue). This does not otherwise appear to impact the functioning
  of the BCHN software on that platform.

• With a certain combination of build flags that included disabling
  the QR code library, a build failure was observed where an erroneous
  linking against the QR code library (not present) was attempted (Issue).

• Possible out-of-memory error when starting bitcoind with high excessiveblocksize
  value (Issue)

• A problem was observed on scalenet where nodes would sometimes hang for
  around 10 minutes, accepting RPC connections but not responding to them
  (see Issue).

• Startup and shutdown time of nodes on scalenet can be long (see Issue).

• Race condition in one of the p2p_invalid_messages.py tests (see Issue).

• Occasional failure in bchn-txbroadcastinterval.py (see Issue).

• wallet_keypool.py test failure when run as part of suite on certain many-core
  platforms (see Issue).

• Spurious 'insufficient funds' failure during p2p_stresstest.py benchmark
  (see Issue).

• If compiling from source, secp256k1 now no longer works with latest openssl3.x series.
  There are workarounds (see Issue).

• Spurious AssertionError: Mempool sync timed out in several tests
  (see Issue).

• For some platforms, there may be a need to install additional libraries
  in order to build from source (see Issue and discussion in MR 1523).

• More TorV3 static seeds may be needed to get -onlynet=onion working
  (see Issue).

• Memory usage can be very high if repeatedly doing RPC getblock with
  verbose=2 on a hash of known big blocks (see Issue).

• A GUI crash failure was observed when attempting to encrypt a large imported
  wallet (see Issue).

• Nodes on 32-bit platforms could fail if blocks reach a size over 1GiB
  (per ABLA this would take multiple years, and by then 32-bit platforms
  will no longer be supported in any case).
  Technically, this is because blocks may take 2x-3x as much memory when
  unserialized into memory as they do when serialized, and 32-bit machines
  often cannot address more than 2GiB in a userspace process, and can never
  address more than 4GiB.

• The 'wallet_multiwallet' functional test fails on latest Arch Linux due to
  a change in semantics in a dependency (see Issue). This is not
  expected to impact functionality otherwise, only a particular edge case
  of the test.

• The 'p2p_extversion' functional test is sensitive to timing issues when
  run at high load (see Issue).

---

Changes since Bitcoin Cash Node 27.0.0

New documents

None

Removed documents

None

Notable commits grouped by functionality

Security or consensus relevant fixes

• 2443f18 Add checkpoints for blocks after upgrade10 ABLA activation
• 7f86271 Switch ABLA (upgrade10) to use height-based activation, rather than MTP
• 399f414 qa: Update chainparams assumevalid and minimumchainwork for 27.1.0
• 02c658c Update chainTxData for main, test3, test4, and chipnet

Interfaces / RPC

None

Features in internal development: support for UTXO commitments

None

Data directory changes

• c64905b Fix for wrong behavior for conf file datadir= inside vs outside a secton

Performance optimizations

None

GUI

None

Code quality

• 4f4fa00 Trivial: Fix compiler warning about unused variable in dsproof_tests.cpp
• 706bc01 Remove deprecated boost::basename method.
• ef2dcc2 Fix compatibility for Boost 1.85 and above
• 368c999 trivial: Fix up the header util/heapoptional.h includes
• 0f6a086 Fix spurious ABLA-related warning for pruned nodes

Documentation updates

• 3c13771 Update copyright year to 2024
• 633908d clarify links and link contribution guide from docs
• 6fbefbf Include onlynet option in example bitcoin.conf
• 9ffaa38 Bump version to 27.1.0 + update release-notes to use this version

Build / general

None

Build / Linux

None

Build / Windows

None

Build / MacOSX

None

Tests / test framework

• dba4975 Nit: Fix a missing %s in chip_testing_setup.cpp
• 233c8cf Expected test failure messages regeneration
• 2ff9aea Expand signing serialization VMB tests

Benchmarks

None

Seeds / seeder software

• 93e08e6 Fix seeder checkpoint check
• 9cdabd2 Fixed a rare crash bug when process runs out of file descriptors
• 7ddc65c Fix socket leaks leading to process running out of file descriptors

Maintainer tools

• 6b79e9f linearize: Add the new testnets and rename diskmagic

Infrastructure

None

Cleanup

• 37ac1c6 Deleted comments related to segwit.

Continuous Integration (GitLab CI)

• 610dfff Import CI docker image file
• b7b2e76 ci: Bump docker image buster -> bookworm

Backports

• 975743a Add the the "util::Overloaded" helper for more idiomatic std::variant usage
• 29e9616 net processing: Only send a getheaders for one block in an INV
• 2b56331 Avoid the use of abs64 in timedata
• e5c1897 Simplify orphan processing in preparation for interruptibility
• 1d91bcc MOVEONLY: Move processing of orphan queue to ProcessOrphanTx
• 2189691 Interrupt orphan processing after every transaction
• 25fe0ea Removed BIP70 support
• d5e0e02 Add txrequest module
• dc99597 Add txrequest unit tests
• a44ac5a Add txrequest fuzz tests
• 5b85c5d Change transaction request logic to use txrequest
• 7675a90 Expedite removal of tx requests that are no longer needed
• d9e0b6f Delete limitedmap as it is unused now
• d4075a4 Report and verify expirations
• 63069ce Add "overload' functional test + disable the penalty for PF_RELAY peers
• d01f330 p2p: declare Announcement::m_state as uint8_t, add getter/setter