We're pleased to announce the 0.9.0 release of c-lightning, named by Sebastian Falbesoner.

This is a major release and includes new features, new integrations as well as
major internal refactorings facilitating extensions and future developments.

Highlights for Users

• We can now send multi-part payments as well as keysend spontaneous payments. This complements the support to receive these payments introduced in an earlier release.
  • Large payments will now be split automatically into multiple parts that are more likely to succeed right away, and better protect your privacy.
  • Should a payment not succeed at first we will adaptively split the amount and retry.
• We added support for watchtower plugins that help protect the node's funds while the node is not currently connected to the network.

Highlights for the Network

• Support for optional fields in some messages has been removed, reducing complexity and replacing them with the more modern TLV extensions
• Splitting payments into smaller parts with MPP increases the traffic on the network and improves privacy by making payments look more homogenous. The added traffic provides cover for other payments.

Highlights for Developers

• Extensible payment flow framework in libplugin allowing developers to write custom extensions without having to reinvent the wheel.
• Added RPC methods to create, sign and send PSBT transactions allowing c-lightning to be better integrated with wallets and higher-level protocols, such as coin-join and dual-funding.
• Added RPC methods to reserve and unreserve outputs controlled by the node to complement the PSBT support, for multi-step protocols.
• Added extensive accounting support in the form of the coin_movement hook that reports any change in the funds controlled by the node.
• Refactored the internals to use PSBT everywhere, leveraging libwally
• A number of new hooks and notifications were added to the plugin interface to allow deeper integration with c-lightning

More details can be found at https://github.com/ElementsProject/lightning/blob/v0.9.0/CHANGELOG.md

Thanks to everyone for their contributions and bug reports; please keep them coming.

Since 0.8.2, we've had 523 commits from 21 different authors.
A special thanks goes to the 8 first time contributors:

• Aiden McClelland @dr-bonez
• Candle @CandleHater
• Joe Miyamoto @joe.miyamoto
• Michal Rostecki @mrostecki
• Reza @rbndg
• Sebastian Falbesoner @theStack
• Vincenzo Palazzo @vincenzopalazzo
• @mb300sd

Cheers,

Christian, Rusty, ZmnSCPxj, and Lisa