LND Software Update Imposes New Fee Estimate Ceiling
The release candidate limits external fee data to 10,000 satoshis per byte to ensure stability in wallet transactions.
Updated on Oct. 26, 2026 in Quantum Computing
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Lightning Network Daemon (LND) has released version 0.21.5-rc, introducing a hard cap on external fee estimates to stabilize wallet operations. This software update prevents erroneous data from impacting fee-sensitive transactions.
Why it matters
The update mitigates risks associated with bad or unusable external fee values, ensuring that automated wallet processes remain performant. By imposing a ceiling on fee data, developers are reducing the potential for disruptions caused by outlier estimates.
The LND 0.21.5-rc update enforces a ceiling of 10,000 satoshis per virtual byte for external fee estimates. This limit is applied before data reaches wallet operations to prevent errors from high-estimate inputs.
The players
Lightning Network Daemon
An implementation of the Lightning Network protocol that enables off-chain Bitcoin transactions via layer-two payment channels.
The details
The update works by intercepting minimum-relay estimates received from external APIs before they trigger fee-sensitive wallet operations. It also includes a fix for a native SQL connection-pool deadlock to improve stability. The build does not require a database migration, simplifying the deployment process for node operators.
Timeline
October 22, 2026: Release candidate 0.21.5 was published.
The Tech Race
This release follows the established pattern of iterative hardening within the Lightning Network protocol stack. It represents a move toward greater robustness in node management as developers continue to refine how off-chain infrastructure handles external data inputs.
Node operators running this software build should expect increased stability during fee-sensitive operations without the need for complex database migrations. The cap acts as a safeguard against corrupted external inputs, shielding current wallet workflows from unexpected estimate spikes.
The takeaway
Reliable fee estimation remains a critical bottleneck for automated payment routing in off-chain systems. Node maintainers should monitor the GitHub repository for the transition from the release candidate to a final stable version of 0.21.5.
Further reading
Learn more about the infrastructure powering secure digital payments on our Quantum Computing page.
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