Newsletters: add 419 (2026-08-21)

_posts/en/newsletters/2026-08-21-newsletter.md

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+---
+title: 'Bitcoin Optech Newsletter #419'
+permalink: /en/newsletters/2026/08/21/
+name: 2026-08-21-newsletter
+slug: 2026-08-21-newsletter
+type: newsletter
+layout: newsletter
+lang: en
+---
+FIXME:bitschmidty
+
+## News
+
+FIXME:bitschmidty
+
+## Changes to services and client software
+
+*In this monthly feature, we highlight interesting updates to Bitcoin
+wallets and services.*
+
+- **Payjoin Dev Kit (rust-payjoin) 1.0.0 released:**
+  The Payjoin Dev Kit project [released][payjoin 1.0.0] the first stable version
+  of rust-payjoin, supporting both synchronous BIP78 [payjoins][topic payjoin]
+  and asynchronous BIP77 payjoins with resumable, persisted sessions.
+
+- **Silent Payments sender plugin for Electrum:**
+  Ali Sherief [released][sp electrum delving] a plugin that adds [silent
+  payments][topic silent payments] (BIP352) sending (no receiving) to the
+  Electrum desktop wallet for single-signature software wallets.
+
+- **Superscalar implementation announced:**
+  8144225309 [announced][superscalar delving] an implementation of Superscalar,
+  ZmnSCPxj's [channel factory][topic channel factories] design that puts many
+  self-custodial Lightning clients behind a single onchain UTXO without a soft
+  fork (see our [Superscalar deep dive podcast][superscalar deepdive]).
+
+- **Cofund multisig wallet announced:**
+  Cofund [announced][cofund x] a self-custody [multisig][topic multisignature]
+  wallet built on a policy-based [taproot][topic taproot] (P2TR) architecture
+  with multi-vendor key registration and hierarchical multisig.
+
+- **Lexe adds human-readable addresses and LNURL-withdraw:**
+  Lexe, a self-custodial Lightning wallet that runs each user's node in a
+  trusted execution environment (TEE) so it stays online without the operator
+  taking custody, [announced][lexe x] support for [BIP353][] human-readable
+  bitcoin addresses (which also function as Lightning Addresses) and
+  [LNURL-withdraw][topic lnurl].
+
+- **Ledger Bitcoin app 2.5.0 adds human-readable policy descriptions:**
+  Salvatore Ingala [announced][salvatoshi x] version 2.5.0 of the Ledger Bitcoin
+  app, which displays a human-readable description for many [taproot][topic
+  taproot] [miniscript][topic miniscript] and [multisig][topic multisignature]
+  wallet policies during registration, instead of only the opaque
+  [descriptor][topic descriptors] template. This makes it easier for a user to
+  verify a policy and catch a malicious substitution (such as a 3-of-5 replaced
+  with a 1-of-5) before registering it.
+
+- **Bark 0.5.0 released:**
+  Second [released][second x] version 0.5.0 of Bark, its [Ark][topic ark]
+  implementation, adding restoration of a wallet's full off-chain balance
+  (VTXOs) from its mnemonic and support for Lightning receives to external Ark
+  addresses, which enables non-custodial Lightning-address servers.
+
+- **Bitcoin-PIR for private UTXO queries:**
+  Weikeng Chen [announced][bitcoinpir] Bitcoin-PIR, a private information
+  retrieval (PIR) system that lets a light client check the UTXO set for its own
+  addresses or scriptPubKeys without revealing to the server which ones it is
+  interested in. It offers a choice of four PIR backends: DPF-PIR, HarmonyPIR,
+  OnionPIRv2, and an ORAM scheme backed by a trusted execution environment
+  (TEE).
+
+- **OP_TEMPLATEHASH Ark demonstration:**
+  Steven Roose [launched][templatehash] a signet demonstration of Bark, Second's
+  [Ark][topic ark] implementation, running against `OP_TEMPLATEHASH`, a
+  taproot-native [CTV][topic op_checktemplateverify]-style [covenant][topic
+  covenants] opcode. The demo is built from the `templatehash` branch of the
+  Bark [repository][bark gitlab].
+
+- **libshrincs formally verified hash-based signatures:**
+  Jonas Nick [announced][libshrincs delving] libshrincs, a C implementation of
+  [post-quantum][topic quantum resistance] hash-based signatures with a
+  machine-checked security proof, written by remix7531.
+
+## 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="2026-08-25 16:30" %}
+{% include references.md %}
+{% include linkers/issues.md v=2 issues="" %}
+
+[payjoin 1.0.0]: https://github.com/payjoin/rust-payjoin/releases/tag/payjoin-1.0.0
+[sp electrum delving]: https://delvingbitcoin.org/t/silent-payments-sender-bip352-plugin-for-electrum/2743
+[superscalar delving]: https://delvingbitcoin.org/t/superscalar-an-implementation-report/2705
+[superscalar deepdive]: /en/podcast/2024/10/31/
+[cofund x]: https://x.com/getcofund/status/2085389177193972164
+[lexe x]: https://x.com/lexeapp/status/2079245197817548964
+[salvatoshi x]: https://x.com/salvatoshi/status/2086727660353261863
+[second x]: https://x.com/secondhq/status/2084716752789991614
+[bitcoinpir]: https://bitcoinpir.org
+[templatehash]: https://templatehash.com
+[bark gitlab]: https://gitlab.com/ark-bitcoin/bark
+[libshrincs delving]: https://delvingbitcoin.org/t/libshrincs-a-c-implementation-with-a-machine-checked-security-proof/2795