In the last ~5 days Megalith LSP ( https://megalithic.me/ ) has seen an upsurge in issues reported by Core Lightning users, where Core Lightning nodes are unable to maintain a connection to our LSP.
Our theory that this is related to the “message padding” issue introduced in CLN 26.04, and fixed in 26.06.
Does anyone know what version of CLN that Umbrel is currently shipping?
If anyone is on 26.04 or 26.06 and can help us troubleshoot, please contact us: Megalithic.me - Contact Us
Yes. As of June 7, 2026, Umbrel’s Core Lightning app page says Umbrel is shipping:
Core Lightning v26.06.1
CLN Application remains v26.04
Umbrel’s changelog shows it was on Core Lightning v26.04.1 about two weeks ago, then updated to 26.06 one day ago, and 26.06.1 today.
The padding theory is plausible: Core Lightning’s v26.04 release notes say peer messages were changed to be padded to a uniform length.
You could reply with:
Umbrel’s current Core Lightning app appears to be shipping Core Lightning v26.06.1 as of today. The Umbrel app-store changelog says “CLN Application remains on v26.04,” but the actual Core Lightning daemon was updated to v26.06, then v26.06.1. It was previously shipping v26.04.1 around two weeks ago, so affected users may still be on 26.04/26.04.1 if they have not updated their Umbrel app yet.
For users checking their own node, they can run something like:
lightning-cli getinfo
and look for the version field. On Umbrel, they may need to run it inside the Core Lightning container, depending on their setup.