Core Lightning v26.04 “Negative Routing Fees” is now available, it's Blockstream’s latest update to our implementation of the Lightning Network. This release makes Core Lightning nodes more flexible, more private, and easier to operate at scale.
A standing splice-ovation: Channel Liquidity, Unlocked
We'll let you off the hook if you haven't been closely following the rise of Splicing, which is being welcomed out of experimental in this release, truly deserving of a standing… splice-ovation. Those in the details truly understand the power of Splicing and its ability to alter the network as we know it.
Splicing explained by Dusty, is a simple concept: the ability to resize Lightning channels. The capability provides many additional benefits that fundamentally improve the utility of Lightning.
Splicing removes the need for expensive closing and opening of channels. This dramatically lowers operating costs, complexity, and idle capital challenges faced when operating a Lightning node. Splicing does this by enabling the direct transfer of funds between "Lightning accounts", at the lowest cost possible. Even better, splicing makes the network more robust by helping these mini Lightning banks stay independent — ending their reliance on "centralized liquidity providers."
This dynamic Lightning experience with Splicing on core-lightning means liquidity management becomes continuous rather than disruptive. By allowing node operators to rebalance liquidity without closing channels, reducing downtime and on-chain overhead through:
splicein: for convenient splicing funds into a channelspliceout: removing funds from a channel. Plus: an added bonus: you can now initiate a splice across two channels usingspliceoutwith a channel identifier as the destination.- cross-splicing: moving liquidity directly between channels
DustyDaemon, a passionate, highly valued, open-source contributor to Core Lightning has brought Splicing from a concept (in 2022) to changing the network as we know it today. That's a seriously long term commitment to Lightning in general, with Core-Lightning front of mind.
So get up out of your seats again, Dusty deserves a standing… splice-ovation of his own. He tells us:
This is the first release where massive many channel splices are fully tested and supported. For example, splice funds out of 5 channels and into 2 other channels all in one command: dev-splice. These scripts allow you to specify any number of splice actions in a clean simplified syntax.... Splicing is truly unleashed for elite channel routing. Up your node’s efficiency game by utilizing the power of splicing!Respect the bookkeepers
We’ve improved the output of Core Lightning’s bookkeeper plugin to better meet global accounting standards. This gives you control to map your node’s activity into journal entries, General Ledger accounts, and audit-ready records.
Building on the bookkeeper updates of 25.09 and 25.12, we have added the ability to:
- Record the at-time Bitcoin to fiat currency conversion rate for each bookkeeper event,
- Create summaries of bookkeeper income, flexibly! You can specify the format, using tags, to whatever accounting standards you prefer, and
- Easily examine the current values from the
currencyconvertplugin's sources
More Reliable Payments, Less Guesswork
Routing improvements continue to be a major focus area. Routing improvements mean payment success and payment success is at the top of everyone’s mind… after all, we are a *cough-cough* payment network.
This release enhances payment success rates through:
- parallel path finding improvements in the
askreneengine. - smarter retry logic and bug fixes across payment flows.
- better control over routing via payment fronting nodes.
Users can now attach a payer-note to xpay payments, making it easier to send a message with your payment.
Better Visibility Into Channels and Offers
v26.04 includes several usability improvements that make it easier to inspect and manage node state:
listpeerchannelsnow supports filtering bychannel_id- Offer RPCs expose decoded descriptions directly
- Enhanced support for BOLT11 and BOLT12 flows via fronting nodes
These changes reduce friction for operators and developers alike, especially when debugging or integrating with higher-level applications.
A Leaner, Faster Node
Under the hood, Core Lightning continues its trend toward efficiency and scalability.
This release delivers:
- ~20% smaller binaries
- faster startup times via gossip store compaction offloading
- improved logging with a more efficient ring buffer
- reduced database and runtime overhead
For large node runners, these improvements translate into faster sync times and smoother operation.
Developer Experience: More Power, Less Friction
These improvements make it easier to build, extend, and operate Core Lightning in production environments, including:
- Dynamic REST endpoints via
clnrest-register-path - simplified Bitcoin backend interactions with a synchronous
bcliplugin - plugin options that support multiple values (
"multi": true) - stricter database safety guarantees with STRICT tables
Core Lightning remains the most extensible Lightning implementation, and these are just a few examples of how v26.04 continues to invest in developer tooling.
Privacy and Protocol Alignment
This release strengthens Core Lightning’s alignment with the BOLTs: Lightning protocol and privacy expectations to ensure interoperability and improve our resistance to network-level observation through:
- removal of legacy onion formats, matching current ecosystem behavior
- we now pad all peer messages to make them the same length to reduce traffic analysis (excluding LND < v21 and current Eclair).
Acknowledgements
Core Lightning doesn’t just happen. Since v25.12, we have merged 421 commits in 110 days by 23 authors, reflecting the serious momentum of our Core Lightning ecosystem. A huge thanks to all contributors for their continued dedication to this project to make this release possible
A special mention to our newest contributors: @ScuttoZ @Raimo33 @TatianaMoroz @dovgopoly @erdoganishe and @Nazarevsky.
Blockstream’s core-core-lightning team for their continued dedication to this project: Rusty Russell, Shahana Farooqui, Sangbida Chaudhuri, Christian Decker, Lagrang, Peter Neuroth and Lisa Neigut, Daywalker and Níckolas Goline.
And to our extended team of contributors: Oleg Fomenko, Ihor Diachenko, Illia Dovhopolyi, Mykhailo Khotian, Nazarii Shcherbak, Eduard Mikhrin, Zakhar Naumets, Vladyslav Doronchenkov, Emanuele Napoli, Federico Scutti, and Mattia Simeone.
Another special mention here to celebrate @dusty_daemon, for his enormous efforts with Splicing implementation and maintainer of the Splicing spec. Dusty has been working on full time Lightning development since 2021. In 2022, Dusty dedicated himself to developing Splicing code, and created code that accomplishes the task, he finished the first splice on chain on May 2, 2022!
Big props also go to @chand-ra who dutifully lived up to the IYKYK vibe of naming duties and Sangbida Chaudhuri for your calm, considered and seamless release-captaining journey.
To all of our loyal open source community members contributing to this project, thank you!
Go fourth and cln!
As always, we encourage node operators to upgrade, test, and provide feedback as we continue refining and improving the Lightning experience.
You can find the full changelog and upgrade instructions on GitHub.