lightning-terminal multi: bump Loop to v0.20.0-beta, lnd min version to 0.15.0

Fixes https://github.com/lightninglabs/lightning-terminal/issues/394.

Bumps the version of Loop to v0.20.0-beta and with that the minimum required version of a remote lnd node to v0.15.0-beta.

This will be released as v0.7.1-alpha.

Jul 25 '22 17:07 guggero

Also, can we update the protos to match the new Loop version here?

Jul 27 '22 16:07 jamaljsr

Shouldn't bitcoind version be enforced on the LND side? @guggero

Do you still have the nautilus logs? The "invalid sweep" error comes from the server side, might give us more insight of what went wrong.

Jul 27 '22 16:07 bhandras

Shouldn't bitcoind version be enforced on the LND side? @guggero

Do you still have the nautilus logs? The "invalid sweep" error comes from the server side, might give us more insight of what went wrong.

Hmm it seems to me the bitcoind version is not available through RPC.

Jul 27 '22 16:07 bhandras

Shouldn't bitcoind version be enforced on the LND side? @guggero

Hmm, no, we didn't actually add that with Taproot. Might be something to think about in lnd 0.15.1? There might be a field to detect the version from indirectly.

Jul 27 '22 16:07 guggero

Do you still have the nautilus logs? The "invalid sweep" error comes from the server side, might give us more insight of what went wrong.

Here are the full litd and nautilus logs. litd.log nautilus.log

Jul 27 '22 16:07 jamaljsr

Do you still have the nautilus logs? The "invalid sweep" error comes from the server side, might give us more insight of what went wrong.

Here are the full litd and nautilus logs. litd.log nautilus.log

Okay what happened here is that the 100 blocks were quickly mined but the client only tried to sweep twice after that. I think if we were to mine 9 more blocks, the client would have tried to sweep on the script path, however would have failed in perpetuity from there since again bitcoind would not consume that transaction.

Jul 27 '22 17:07 bhandras

Current plan of record: The path forward here is update lnd to have this flag that catches the bitcoind version and ensures that musig2 loop outs are only attempted with the compatible backend. once that's done in lnd 0.15.1 then we'd cut a new loop client and then cut a new litd.

Jul 27 '22 23:07 levmi

@guggero, remember to re-request review from reviewers when ready

Sep 15 '22 04:09 lightninglabs-deploy

Will be replaced by https://github.com/lightninglabs/lightning-terminal/pull/418.

Sep 15 '22 10:09 guggero