What's new

Some of more notable changes introduced in Bitcoin Core v28 include:

• Testnet4/BIP94 Support. Support for Testnet4 as specified in BIP94 has been added. Testnet3 will be phased out in an upcoming version.
  • The BIP94 timewarp attack mitigation is now active on the regtest network.
• Opportunistic one-parent-one-child (1p1c) package relay. Transactions with low fee rates can be paired with their child transactions and submitted as a package, allowing nodes to download 1-parent-1-child packages via the transaction relay protocol.
• Default relay of opt-in topologically restricted until confirmation (TRUC) transactions. The new policy includes limits on spending unconfirmed outputs, eviction of a previous descendant if a more incentive-compatible one is submitted, and a maximum transaction size of 10,000vB.
  • "These restrictions simplify the assessment of incentive compatibility of accepting or replacing TRUC transactions, thus ensuring any replacements are more profitable for the node and making fee-bumping more reliable."
• Default relay of pay-to-anchor (P2A) transactions. Pay To Anchor is a new standard witness output type for spending, a newly recognized output template.
• Limited package RBF relay. Limited package RBF is now enabled, where the proposed conflicting package would result in a connected component, aka cluster, of size 2 in the mempool. All clusters being conflicted against must be of size 2 or lower.
• Full RBF by default. The default value of the -mempoolfullrbf configuration option has been changed from 0 to 1, i.e. mempoolfullrbf=1.
• AssumeUTXO available on mainnet. AssumeUTXO mainnet parameters have been added for height 840,000. The loadtxoutset RPC can now be used on mainnet with the matching UTXO set from that height.
• New Windows Data Directory. The default Windows data directory has been moved to C:\Users\Username\AppData\Local\Bitcoin. If old directory is present, the client will continue to use it for backwards compatibility.
• JSON-RPC 2.0 Support. The JSON-RPC server now recognizes JSON-RPC 2.0 requests and responds with strict adherence to the specification.
  • "JSON-RPC clients may need to be updated to be compatible with the JSON-RPC server. Please open an issue on GitHub if any compatibility issues are found."
• libbitcoinconsensus Removal. The libbitcoin-consensus library was deprecated in 27.0 and is now completely removed.
• Easier to migrate legacy wallets to descriptor wallet format.
  • The "Migrate Wallet" menu allows users to migrate any legacy wallet in their wallet directory, regardless of the wallets loaded.
  • A new createwalletdescriptor RPC allows users to add new automatically generated descriptors to their wallet. This can be used to upgrade wallets created prior to the introduction of a new standard descriptor, such as taproot.
• Blockstorage improvements. Block files are now XOR'd by default with a key stored in the blocksdir.
• Maximum mempool size along with the mempool usage are now displayed in the "Information" window.
• UNIX domain sockets can now be used for proxy connections.
• GCC 11.1 or later, or Clang 16.0 or later, are now required to compile Bitcoin Core.
• The minimum required glibc to run Bitcoin Core is now 2.31. This means that RHEL 8 and Ubuntu 18.04 (Bionic) are no-longer supported.