The new update introduces improvements in network management and mempool policies.
On April 15th, Bitcoin Core 29.0 was released, an update that introduces several technical innovations and improves the stability and performance of the Bitcoin network, with changes that optimize the developer experience.
Improvements in the P2P network
One of the main changes in Bitcoin Core 29.0 is the abandonment of UPnP support in favor of NAT-PMP/PCP, a more modern implementation for managing network connections. This modification improves the security and reliability of connections, also introducing support for IPv6 “pinholing”. Users who were using the -upnp option will now receive a warning and the system will automatically treat this parameter as -natpmp.
The update also offers more reliable handling of “orphan” transactions (unconfirmed transactions that spend unknown inputs), with the node now attempting to download missing transactions from nodes that announced the orphan, thus improving transaction propagation across the network.
Innovation with “Ephemeral Dust”
A relevant innovation is the introduction of the concept of “ephemeral dust”, that is, tiny transaction outputs below the dust limit, which are produced in a fee-free v3 transaction and consumed in a subsequent v3 transaction. These temporary outputs, created and spent within the same transaction package, represent an improvement for various applications, such as Lightning Network, Ark, ln-symmetry, Spacechains, and Timeout Trees.
Full RBF as standard
With version 29.0, the Replace-by-Fee (RBF) protocol becomes the official standard. The -mempoolfullrbf option, introduced in previous versions, has been completely removed, making RBF the default behavior for all nodes. Before this version, when sending a transaction, one had to specify before sending whether they intended to use the RBF option. With Bitcoin Core 29.0, any transaction in the mempool can be replaced. This implies that “zero-conf” transactions (zero confirmations) no longer exist, as any transaction could be replaced with one that pays higher fees or has a different recipient.
End of support for previous versions
With the release of Bitcoin Core 29.0, versions 26.x and earlier have reached “Maintenance End” and will no longer receive updates. Two weeks after the release of version 29.0, medium and high severity vulnerabilities affecting version 26.x will be disclosed, as well as low severity vulnerabilities affecting 28.x, in line with the security policy.
