Electrum’s newest safety replace fixes a Lightning backup defect, however some Bitcoin pockets customers nonetheless want to interchange saved backups.
Older backups from wallets with non-deterministic Lightning keys lack info wanted to reclaim funds from anchor channels, a Lightning channel sort, after a distant shut.
Model 4.8.2, dated Sept. 11, stays the newest launch listed on Electrum’s official web site as of Oct. 1.
The person-backup repair provides payment-key info wanted to say the consumer’s steadiness from an anchor channel closed by the peer. With out that info, an affected backup lacks the important thing wanted to comb the output, that means declare the cash on the Bitcoin blockchain.
Which wallets want consideration?
Electrum’s launch notes outline two situations that should coincide: the pockets has non-deterministic Lightning keys, and the backup considerations an anchor channel.
Non-deterministic keys can’t be recreated from the pockets’s seed. The warning covers particular person channel exports and exported full-wallet backups regarding Lightning restoration.
Lightning wallets based mostly on BIP39 seeds or imported prolonged non-public keys (xprvs) all the time have non-deterministic Lightning keys. Electrum-seed wallets differ: their Lightning keys are deterministic when the pockets file was created in model 4.1 or later. Recordsdata created in 4.0.x don’t qualify merely as a result of the software program is now newer.
On desktop, pockets info marks the Lightning channels as non-recoverable from the seed, whereas the channel-opening dialog warns {that a} channel can’t be recovered from the seed on Android. Anchor-channel use stays the extra situation for this backup defect.
The person-backup repair additionally hides the choice to request a distant force-close when the backup can’t sweep the ensuing output. The restriction retains that backup from requesting a detailed whose output it can’t declare.
PR 10851 repairs wallet-file exports by retaining a randomly generated Lightning non-public key that the export beforehand deleted. Maintainer SomberNight explains that re-enabling Lightning in such a backup would generate totally different keys, leaving its older channel-backup information inadequate to spend anchor-channel funds.
An improve adjustments the software program that produces and reads backups. Electrum’s documented treatment subsequently requires contemporary exports, and affected wallets show a startup warning.
The substitute step will depend on retaining the unique pockets information wanted for a contemporary export. Putting in newer software program doesn’t assure restoration of key materials already misplaced with that information.
