eclair/docs/release-notes/eclair-vnext.md

Eclair vnext

Major changes

Use priority instead of block target for feerates

Eclair now uses a slow/medium/fast notation for feerates (in the style of mempool.space), instead of block targets. Only the funding and closing priorities can be configured, the feerate for commitment transactions is managed by eclair, so is the fee bumping for htlcs in force close scenarii. Note that even in a force close scenario, when an output is only spendable by eclair, then the normal closing priority is used.

Default setting is medium for both funding and closing. Node operators may configure their values like so:

eclair.on-chain-fees.confirmation-priority {
    funding = fast
    closing = slow
}

This configuration section replaces the previous eclair.on-chain-fees.target-blocks section.

Managing Bitcoin Core wallet keys

You can now use Eclair to manage the private keys for on-chain funds monitored by a Bitcoin Core watch-only wallet.

See docs/BitcoinCoreKeys.md for more details.

Advertise low balance with htlc_maximum_msat

Eclair used to disable a channel when there was no liquidity on our side so that other nodes stop trying to use it. However, other implementations use disabled channels as a sign that the other peer is offline. To be consistent with other implementations, we now only disable channels when our peer is offline and signal that a channel has very low balance by setting htlc_maximum_msat to a low value. The balance thresholds at which to update htlc_maximum_msat are configurable like this:

eclair.channel.channel-update {
    balance-thresholds = [{
        available-sat = 1000  // If our balance goes below this,
        max-htlc-sat =  0     // set the maximum HTLC amount to this (or htlc-minimum-msat if it's higher).
    },{
        available-sat = 10000
        max-htlc-sat =  1000
    }]

    min-time-between-updates = 1 hour // minimum time between channel updates because the balance changed
}

This feature leaks a bit of information about the balance when the channel is almost empty, if you do not wish to use it, set eclair.channel.channel-update.balance-thresholds = [].

API changes

• bumpforceclose can be used to make a force-close confirm faster, by spending the anchor output (#2743)
• open now takes an optional parameter --fundingFeeBudgetSatoshis to define the maximum acceptable value for the mining fee of the funding transaction. This mining fee can sometimes be unexpectedly high depending on available UTXOs in the wallet. Default value is 0.1% of the funding amount (#2808)
• rbfopen now takes a mandatory parameter --fundingFeeBudgetSatoshis, with the same semantics as for open (#2808)

Miscellaneous improvements and bug fixes

Verifying signatures

You will need gpg and our release signing key 7A73FE77DE2C4027. Note that you can get it:

• from our website: https://acinq.co/pgp/drouinf.asc
• from github user @sstone, a committer on eclair: https://api.github.com/users/sstone/gpg_keys

To import our signing key:

$ gpg --import drouinf.asc

To verify the release file checksums and signatures:

$ gpg -d SHA256SUMS.asc > SHA256SUMS.stripped
$ sha256sum -c SHA256SUMS.stripped

Building

Eclair builds are deterministic. To reproduce our builds, please use the following environment (*):

• Ubuntu 22.04
• AdoptOpenJDK 11.0.6
• Maven 3.9.2

Use the following command to generate the eclair-node package:

mvn clean install -DskipTests

That should generate eclair-node/target/eclair-node-<version>-XXXXXXX-bin.zip with sha256 checksums that match the one we provide and sign in SHA256SUMS.asc

(*) You may be able to build the exact same artefacts with other operating systems or versions of JDK 11, we have not tried everything.

Upgrading

This release is fully compatible with previous eclair versions. You don't need to close your channels, just stop eclair, upgrade and restart.

Changelog

<fill this section when publishing the release with git log v0.9.0... --format=oneline --reverse>