The Bitcoin Core development team recently announced the official release of Bitcoin Core v29.0, a major update delivering critical enhancements to network reliability, transaction handling, and developer infrastructure.
This release marks a pivotal step forward in optimizing bitcoin’s node software for modern use cases, including Layer 2 solutions like the Lightning Network, while phasing out legacy systems and improving security standards.
Key Network and Security Enhancements
Bitcoin Core v29.0 eliminates reliance on the outdated UPnP (Universal Plug and Play) protocol, replacing it with NAT-PMP and PCP for more secure and efficient network address translation. This shift modernizes node connectivity, supports IPv6 pinholing, and reduces vulnerabilities associated with older protocols. 
The update also introduces enhanced orphan transaction handling, ensuring nodes more reliably download missing parent transactions from peers. While this may increase bandwidth usage slightly, it significantly improves transaction processing robustness.
Security Alert: Versions 26.x and older have reached end-of-life status, with critical vulnerability disclosures scheduled two weeks post-release. Users are urged to upgrade immediately to avoid exposure.
Advanced Mempool Policies for Scalability
A standout feature of v29.0 is the introduction of ephemeral dust outputs—tiny, temporary transaction outputs designed for Lightning Network channels, Ark, and other Layer 2 protocols.
These outputs are created and spent within the same transaction package, enabling fee flexibility while adhering to Bitcoin’s anti-spam rules.
Additionally, the release fixes a longstanding block size handling bug by introducing the -blockreservedweight option. This ensures blocks utilize their full capacity while maintaining compatibility with existing setups.
Developer-Focused Tools and RPC Improvements
The update standardizes full replace-by-fee (RBF) behavior by removing the -mempoolfullrbf option, aligning with industry-wide adoption of transaction replacement policies.
Enhanced RPCs now provide detailed error diagnostics, including a new reject-details field in testmempoolaccept for troubleshooting transaction rejections. The getdescriptoractivity RPC enables precise tracking of wallet descriptor activity, reducing reliance on third-party indexing tools.
Developers will also benefit from doubled RPC thread limits (-rpcthreads increased to 16, -rpcworkqueue to 64) and improved handling of negated configuration options like -noseednode.
Infrastructure and Build System Modernization
Bitcoin Core’s build system has transitioned from Autotools to CMake, streamlining cross-platform development. This change, requiring CMake 3.22 or newer, enhances flexibility for contributors and aligns with modern software practices.
Dependencies on MiniUPnPc and libnatpmp have been fully removed, simplifying code maintenance.
Upgrade Urgency and Resources
Users of Bitcoin Core 26.x or earlier must upgrade immediately to avoid security risks. The release includes critical fixes for block reservation, pruning behavior, and timewarp attack mitigations.
For full details, visit the Bitcoin Core GitHub repository or review the v29.0 release notes.
About Bitcoin Core
Bitcoin Core is the open-source software implementation powering the Bitcoin network. Maintained by a global decentralized community, it ensures the integrity and advancement of the Bitcoin protocol.
