Newsletters: add 389 (2026-01-23)

_posts/en/newsletters/2026-01-23-newsletter.md

@@ -0,0 +1,100 @@
+---
+title: 'Bitcoin Optech Newsletter #389'
+permalink: /en/newsletters/2026/01/23/
+name: 2026-01-23-newsletter
+slug: 2026-01-23-newsletter
+type: newsletter
+layout: newsletter
+lang: en
+---
+This week's newsletter links to a paper on the study of payment channel networks.
+Also included are our regular sections describing recent updates to services and
+client software, announcing new releases and release candidates, and summarizing
+notable changes to popular Bitcoin infrastructure software.
+
+## News
+
+- **A mathematical theory of payment channel networks**: René Pickhardt [posted][channels post]
+  about the publication of his new [paper][channels paper] called "A Mathematical Theory of
+  Payment Channel Network". In the paper, Pickhardt groups several observations, gathered
+  during years of research, under a single geometric framework. In particular, the paper aims to
+  analyze common phenomena, such as channel depletion and capital innefficiencies of two-party
+  channels, assessing how they are inter-connected and why they are true.
+
+  The main paper contributions are the following:
+
+  - A model for feasible wealth distributions of users on the lightning network
+    given a channel graph;
+
+  - A formular for estimating the upper bound of payment bandwidth for payments;
+
+  - A method to estimate the likelihood that a payment is feasible (see
+    [Newsletter #309][news309 feasibility]);
+
+  - An analysis on different
+    [mitigation strategies][mitigation post] for channel depletion.
+
+  - The conclusion that two-party channels put strong constraints to the ability of liquidity to
+    flow between peers of the network.
+
+  According to Pickhardt, the insights coming from his research were the motivation behind his
+  recent post about using Ark as a channel factory (see [Newsletter #387][new387 ark]).
+  Pickhardt also provided his [collection][pickhardt gh] of code, notebooks, and papers that
+  were used as groundwork for his research.
+
+  Finally, Pickhardt opened the discussion on his work to questions and feedback from the LN
+  developer community on how the protocol design could be influenced by his research and on
+  the best use for multi-party channels.
+
+## Changes to services and client software
+
+*In this monthly feature, we highlight interesting updates to Bitcoin
+wallets and services.*
+
+- **Experimental Electrum server for testing silent payments:**
+  [Frigate Electrum Server][frigate gh] implements the [remote scanner][bip352
+  remote scanner] service from [BIP352][] to provide [silent payment][topic
+  silent payments] scanning for client applications. The proof of concept also
+  uses modern GPU computation to decrease scanning time which is useful for
+  providing multi-user instances that handle many simultaneous scanning requests.
+
+- **BDK WASM library:**
+  The [bdk-wasm][bdk-wasm gh] library, originally developed and [used][metamask
+  blog] by the MetaMask organization, provides access to BDK features in
+  environments that support WebAssembly (WASM).
+
+## Releases and release candidates
+
+_New releases and release candidates for popular Bitcoin infrastructure
+projects.  Please consider upgrading to new releases or helping to test
+release candidates._
+
+FIXME:Gustavojfe
+
+## Notable code and documentation changes
+
+_Notable recent changes in [Bitcoin Core][bitcoin core repo], [Core
+Lightning][core lightning repo], [Eclair][eclair repo], [LDK][ldk repo],
+[LND][lnd repo], [libsecp256k1][libsecp256k1 repo], [Hardware Wallet
+Interface (HWI)][hwi repo], [Rust Bitcoin][rust bitcoin repo], [BTCPay
+Server][btcpay server repo], [BDK][bdk repo], [Bitcoin Improvement
+Proposals (BIPs)][bips repo], [Lightning BOLTs][bolts repo],
+[Lightning BLIPs][blips repo], [Bitcoin Inquisition][bitcoin inquisition
+repo], and [BINANAs][binana repo]._
+
+FIXME:Gustavojfe
+
+{% include snippets/recap-ad.md when="2026-01-27 17:30" %}
+{% include references.md %}
+{% include linkers/issues.md v=2 issues="" %}
+
+[channels post]: https://delvingbitcoin.org/t/a-mathematical-theory-of-payment-channel-networks/2204
+[channels paper]: https://arxiv.org/pdf/2601.04835
+[news309 feasibility]: /en/newsletters/2024/06/28/#estimating-the-likelihood-that-an-ln-payment-is-feasible
+[mitigation post]: https://delvingbitcoin.org/t/mitigating-channel-depletion-in-the-lightning-network-a-survey-of-potential-solutions/1640/1
+[new387 ark]: /en/newsletters/2026/01/09/#using-ark-as-a-channel-factory
+[pickhardt gh]: https://github.com/renepickhardt/Lightning-Network-Limitations
+[frigate gh]: https://github.com/sparrowwallet/frigate
+[bip352 remote scanner]: https://github.com/silent-payments/BIP0352-index-server-specification/blob/main/README.md#remote-scanner-ephemeral
+[bdk-wasm gh]: https://github.com/bitcoindevkit/bdk-wasm
+[metamask blog]: https://metamask.io/news/bitcoin-on-metamask-btc-wallet

_topics/en/silent-payments.md

@@ -83,6 +83,9 @@ optech_mentions:
   - title: "Draft BIP for silent payment descriptors"
     url: /en/newsletters/2026/01/09/#draft-bip-for-silent-payment-descriptors
 
+  - title: "Experimental Electrum server for testing silent payments"
+    url: /en/newsletters/2026/01/23/#experimental-electrum-server-for-testing-silent-payments
+
 ## Optional.  Same format as "primary_sources" above
 see_also:
   - title: Output linking