LND Caps External Bitcoin Fee Estimates at 10,000 Sat/vB

Lightning Network Daemon (LND) has capped estimates from its external fee API at 10,000 satoshis per virtual byte in a release candidate, limiting unusually high inputs that can reach fee-sensitive wallet operations. Version v0.21.5-beta.rc1 was published Thursday, Oct. 22.

Before the change, the external API’s estimates had a lower bound but no upper limit. The new bounds apply to both block-target estimates and the API’s minimum relay feerate, identified in the software as min_relay_feerate.

The ceiling is a software limit on estimates from the external service, not a description of a typical Bitcoin (BTC) transaction fee. Estimates from local bitcoind and btcd backends are unaffected.

The external fee URL is optional in some setups and required when using Neutrino on Bitcoin mainnet. In other configurations, fee estimation depends on the selected backend and network.

The release candidate also fixes a connection-pool deadlock affecting SQLite nodes. Two simultaneous SubscribeInvoices calls with a nonzero settle_index could use all available pool connections, blocking other database access.

LND marks v0.21.5-beta.rc1 as a pre-release. It includes no database migrations.