Electrum Fixes Lightning Backup Flaw, But Older Backups Still Require Replacement

Electrum, a popular Bitcoin wallet, has released a security update to fix a flaw in its Lightning backup feature. The patch, version 4.8.2, addresses a defect that affected anchor channels and required users to replace older backup files.

The issue, which was discovered in the September 11 security update, limited the recoverability of funds from anchor channels for users with non-deterministic Lightning keys. Anchor channels are a type of Lightning channel that allows for multiple payment flows.

The defect required both non-deterministic Lightning keys and anchor channels, making it difficult for users to reclaim their funds. Electrum's release notes state that users with non-deterministic Lightning keys and older backups may still need to replace their saved backups.

According to Electrum's documentation, users who have non-deterministic Lightning keys and backup files created before version 4.1 may still be affected by the defect. However, users who have upgraded to version 4.8.2 or later can export fresh backups that include the necessary payment-key information.