LND releases maintenance candidate addressing database and fee estimate issues

The Lightning Network Daemon (LND) has published a new release candidate, version 0.21.5-beta.rc1, aimed at improving node stability and security. The update focuses on resolving infrastructure faults and implementing guardrails against extreme external data.

A significant fix addresses a database deadlock involving invoice subscriptions and the SQL connection pool. Under certain conditions, simultaneous requests could consume all available connections, causing the entire node to stop responding. The update also modifies how variable-length data is allocated during message decoding to prevent excessive memory commitment based on incoming records.

Additionally, the release introduces a ceiling for Bitcoin fee estimates received via external APIs. By capping estimates at 10,000 satoshis per virtual byte and bounding minimum-relay estimates, the software aims to prevent extreme or erroneous external values from negatively impacting wallet operations. This version is a pre-release intended for testing and does not require database migrations.