Merge branch 'pratik/otel-phase6-statsd' into pratik/otel-phase7-native-metrics

# Conflicts: # .cspell.config.yaml
2026-08-21 14:20:56 +00:00 · 2026-08-20 12:12:36 +01:00
parent ac71480a62 35c3c31b38
commit e6688d8a0b
464 changed files with 27964 additions and 14307 deletions
--- a/.codecov.yml
+++ b/.codecov.yml
@@ -1,10 +1,32 @@
 codecov:
  require_ci_to_pass: true
+  # The C++ and Rust uploads land minutes apart; without this gate Codecov
+  # publishes a near-zero total from whichever one arrives first.
+  notify:
+    after_n_builds: 2
+    wait_for_ci: true

 comment:
  behavior: default
  layout: reach,diff,flags,tree,reach
-  show_carryforward_flags: false
+  show_carryforward_flags: true
+  after_n_builds: 2
+
+# C++ and Rust coverage upload from independent workflows under the `cpp` and
+# `rust` flags; carryforward keeps one language's total when only the other reran.
+flag_management:
+  default_rules:
+    carryforward: true
+  individual_flags:
+    - name: cpp
+      carryforward: true
+      paths:
+        - include/
+        - src/
+    - name: rust
+      carryforward: true
+      paths:
+        - crates/

 coverage:
  range: "70..85"
--- a/.cspell.config.yaml
+++ b/.cspell.config.yaml
@@ -7,6 +7,7 @@ ignorePaths:
  - cmake/**
  - LICENSE.md
  - .clang-tidy
+  - nix/check-tools/*.txt # generated, and full of Nix store hashes
 language: en
 allowCompoundWords: true # TODO (#6334)
 ignoreRandomStrings: true
@@ -69,6 +70,7 @@ words:
  - canonicality
  - CGNAT
  - canonicalised
+  - cctools
  - changespq
  - checkme
  - choco
@@ -112,6 +114,7 @@ words:
  - disablerepo
  - distro
  - doxyfile
+  - dsymutil
  - dxrpl
  - elgamal
  - enabled
@@ -140,6 +143,7 @@ words:
  - gpgcheck
  - gpgkey
  - havetxset
+  - Hinnant
  - hotwallet
  - hicpp
  - htpasswd
@@ -175,6 +179,8 @@ words:
  - llection
  - LOCALGOOD
  - logwstream
+  - Lombrozo
+  - lresolv
  - lseq
  - lsmf
  - ltype
@@ -210,6 +216,7 @@ words:
  - nftokens
  - nftpage
  - nikb
+  - Nikolaos
  - nixfmt
  - nixos
  - nixpkgs
@@ -229,6 +236,7 @@ words:
  - onlatest
  - ostr
  - otelc
+  - otool
  - oxalica
  - pargs
  - partitioner
@@ -263,12 +271,16 @@ words:
  - rcflags
  - reparent
  - replayer
+  - repodata
+  - repomd
  - reqps
  - rerandomize
  - rerandomization
  - rerandomized
  - rerandomizes
  - rerere
+  - retargeted
+  - retargets
  - retriable
  - RIPD
  - ripdtop
@@ -304,6 +316,7 @@ words:
  - sles
  - soci
  - socidb
+  - Sonatype
  - sponsee
  - sponsees
  - SRPMS
@@ -323,6 +336,7 @@ words:
  - summands
  - superpeer
  - superpeers
+  - Swatinem
  - takergets
  - takerpays
  - ters
@@ -380,8 +394,10 @@ words:
  - wthread
  - xbridge
  - xchain
+  - xcrun
  - ximinez
  - XMACRO
+  - xored
  - xrpkuwait
  - xrpl
  - xrpld
@@ -390,3 +406,4 @@ words:
  - xxhasher
  - xychart
  - zpages
+  - zstdio
--- a/.envrc
+++ b/.envrc
@@ -1,3 +1,7 @@
 watch_file nix/*.nix

+# The dev shell derivation includes all of conan/ (see nix/devshell.nix), so any
+# change in there has to invalidate direnv's cached environment.
+watch_dir conan
+
 use flake
--- a/.github/actions/generate-version/action.yml
+++ b/.github/actions/generate-version/action.yml
@@ -1,44 +0,0 @@
-name: Generate build version number
-description: "Generate build version number."
-
-outputs:
-  version:
-    description: "The generated build version number."
-    value: ${{ steps.version.outputs.version }}
-
-runs:
-  using: composite
-  steps:
-    # When a tag is pushed, the version is used as-is.
-    - name: Generate version for tag event
-      if: ${{ startsWith(github.ref, 'refs/tags/') }}
-      shell: bash
-      env:
-        VERSION: ${{ github.ref_name }}
-      run: echo "VERSION=${VERSION}" >>"${GITHUB_ENV}"
-
-    # When a tag is not pushed, then the version (e.g. 1.2.3-b0) is extracted
-    # from the BuildInfo.cpp file and the shortened commit hash appended to it.
-    # We use a plus sign instead of a hyphen because Conan recipe versions do
-    # not support two hyphens.
-    - name: Generate version for non-tag event
-      if: ${{ !startsWith(github.ref, 'refs/tags/') }}
-      shell: bash
-      run: |
-        echo 'Extracting version from BuildInfo.cpp.'
-        VERSION="$(cat src/libxrpl/protocol/BuildInfo.cpp | grep "versionString =" | awk -F '"' '{print $2}')"
-        if [[ -z "${VERSION}" ]]; then
-            echo 'Unable to extract version from BuildInfo.cpp.'
-            exit 1
-        fi
-
-        echo 'Appending shortened commit hash to version.'
-        SHA='${{ github.sha }}'
-        VERSION="${VERSION}+${SHA:0:7}"
-
-        echo "VERSION=${VERSION}" >>"${GITHUB_ENV}"
-
-    - name: Output version
-      id: version
-      shell: bash
-      run: echo "version=${VERSION}" >>"${GITHUB_OUTPUT}"
--- a/.github/actions/release-info/action.yml
+++ b/.github/actions/release-info/action.yml
@@ -0,0 +1,90 @@
+name: Release info
+description: "Derive the version, release channel and package release number for this build."
+
+outputs:
+  version:
+    description: "The build version number."
+    value: ${{ steps.version.outputs.version }}
+  channel:
+    description: "The release channel this build belongs to."
+    value: ${{ steps.channel.outputs.channel }}
+  pkg_release:
+    description: "The package release number: 1 for a tag, the run number otherwise."
+    value: ${{ steps.pkg_release.outputs.pkg_release }}
+
+runs:
+  using: composite
+  steps:
+    # A tag names its own version. Anything else takes it from BuildInfo.cpp and
+    # appends the commit hash as build metadata, joined with a plus sign because a
+    # Conan version cannot contain two hyphens.
+    - name: Determine version
+      id: version
+      shell: bash
+      env:
+        IS_TAG: ${{ startsWith(github.ref, 'refs/tags/') }}
+        REF_NAME: ${{ github.ref_name }}
+        SHA: ${{ github.sha }}
+      run: |
+        if [[ "${IS_TAG}" == "true" ]]; then
+            version="${REF_NAME}"
+        else
+            version="$(awk -F'"' '/versionString =/ { print $2 }' src/libxrpl/protocol/BuildInfo.cpp)"
+            if [[ -z "${version}" ]]; then
+                echo "Unable to read versionString from BuildInfo.cpp." >&2
+                exit 1
+            fi
+            version="${version}+${SHA:0:7}"
+        fi
+
+        echo "version=${version}" | tee -a "${GITHUB_OUTPUT}"
+
+    # Only a tag says how mature a build is: a push is a develop build whatever
+    # its version, and a non-public codebase keeps its packages to itself.
+    - name: Determine release channel
+      id: channel
+      shell: bash
+      env:
+        IS_TAG: ${{ startsWith(github.ref, 'refs/tags/') }}
+        REF_NAME: ${{ github.ref_name }}
+        VISIBILITY: ${{ github.event.repository.visibility }}
+      run: |
+        pre_release=""
+        if [[ "${REF_NAME}" == *-* ]]; then
+            pre_release="${REF_NAME#*-}"
+        fi
+
+        if [[ "${VISIBILITY}" != "public" ]]; then
+            channel=private
+        elif [[ "${IS_TAG}" != "true" ]]; then
+            channel=develop
+        elif [[ -z "${pre_release}" ]]; then
+            channel=stable
+        elif [[ "${pre_release}" =~ ^rc[0-9]+(\+.*)?$ ]]; then
+            channel=unstable
+        elif [[ "${pre_release}" =~ ^b(0|[1-9][0-9]*)(\+.*)?$ ]]; then
+            channel=experimental
+        else
+            echo "Unsupported pre-release in tag '${REF_NAME}'. Use bN or rcN." >&2
+            exit 1
+        fi
+
+        echo "channel=${channel}" | tee -a "${GITHUB_OUTPUT}"
+
+    # A tag is packaged once, so its release number is fixed at 1. Develop builds
+    # repeat the same version, so the run number is what makes each push an
+    # upgrade rather than a reinstall.
+    - name: Determine package release
+      id: pkg_release
+      shell: bash
+      env:
+        IS_TAG: ${{ startsWith(github.ref, 'refs/tags/') }}
+        RUN_NUMBER: ${{ github.run_number }}
+      run: |
+        if [[ "${IS_TAG}" == "true" ]]; then
+            pkg_release=1
+        else
+            pkg_release="${RUN_NUMBER}"
+        fi
+
+        echo "pkg_release=${pkg_release}" | tee -a "${GITHUB_OUTPUT}"
--- a/.github/actions/setup-nix-env/action.yml
+++ b/.github/actions/setup-nix-env/action.yml
@@ -0,0 +1,69 @@
+name: Setup Nix environment
+description: "Build the flake's CI environment and put its tools on PATH."
+
+# The environment from nix/ci-env.nix, the same one the Linux CI images bake in
+# (see nix/docker). Exported onto PATH rather than entered with `nix develop`:
+# the composite actions below run plain `bash` and would escape a dev shell.
+
+runs:
+  using: composite
+
+  steps:
+    - name: Build the CI environment
+      id: build
+      shell: bash
+      env:
+        # --out-link doubles as a GC root for the length of the job.
+        OUT_LINK: ${{ runner.temp }}/xrpld-ci-env
+      run: |
+        # --extra-experimental-features: flakes may not be on in the runner's nix.conf.
+        nix --extra-experimental-features "nix-command flakes" \
+            build .#default --out-link "${OUT_LINK}" --print-build-logs
+        echo "path=$(readlink -f "${OUT_LINK}")" >>"${GITHUB_OUTPUT}"
+
+    - name: Export the environment
+      shell: bash
+      env:
+        ENV_PATH: ${{ steps.build.outputs.path }}
+      run: |
+        echo "${ENV_PATH}/bin" >>"${GITHUB_PATH}"
+
+        # Already KEY=VALUE per line. See `darwinEnv` in nix/ci-env.nix.
+        ENV_FILE="${ENV_PATH}/share/xrpld-ci-env/env"
+        if [ -f "${ENV_FILE}" ]; then
+            cat "${ENV_FILE}" >>"${GITHUB_ENV}"
+        fi
+
+        # XrplSanity.cmake otherwise rejects a Nix compiler as one that leaked.
+        echo "XRPL_DEVSHELL=ci-env" >>"${GITHUB_ENV}"
+
+        # Unlike the Linux nix images, macOS needs no SSL_CERT_FILE: it has its
+        # own trust store, and pinning would break TLS to hosts relying on it.
+
+        # Workspace-local, so `cleanup-workspace` clears it, but not the
+        # `.conan2` prepare-runner hands the system toolchain: that Conan is a
+        # different version, and the two would migrate each other's cache.
+        echo "CONAN_HOME=${{ github.workspace }}/.conan2-nix" >>"${GITHUB_ENV}"
+
+    # Config, profiles and remote, exactly as the dev shell sets them up on
+    # entry; the `setup-conan` action is skipped for this toolchain.
+    - name: Setup Conan
+      shell: bash
+      run: ./conan/init.sh
+
+    # `Check tools` runs later but swallows failures; a bad export would just
+    # build with the system toolchain.
+    - name: Verify the toolchain resolves into the Nix store
+      shell: bash
+      run: |
+        for tool in clang clang++ cmake ninja conan; do
+            path="$(command -v "${tool}" || true)"
+            echo "${tool} -> ${path:-<not found>}"
+            case "${path}" in
+                /nix/store/*) ;;
+                *)
+                    echo "::error::${tool} does not resolve into the Nix store"
+                    exit 1
+                    ;;
+            esac
+        done
--- a/.github/dependabot.yml
+++ b/.github/dependabot.yml
@@ -4,7 +4,7 @@ updates:
    directories:
      - /
      - .github/actions/build-deps/
-      - .github/actions/generate-version/
+      - .github/actions/release-info/
      - .github/actions/set-compiler-env/
      - .github/actions/setup-conan/
    schedule:
@@ -19,3 +19,19 @@ updates:
      github-actions:
        patterns:
          - "*"
+
+  - package-ecosystem: cargo
+    directory: /crates
+    schedule:
+      interval: weekly
+      day: monday
+      time: "04:00"
+      timezone: Etc/GMT
+    commit-message:
+      prefix: "chore: [DEPENDABOT] "
+    target-branch: develop
+    open-pull-requests-limit: 10
+    groups:
+      rust-dependencies:
+        patterns:
+          - "*"
--- a/.github/scripts/rename/binary.sh
+++ b/.github/scripts/rename/binary.sh
@@ -49,7 +49,7 @@ ${SED_COMMAND} -i -E 's@ripple/xrpld@XRPLF/rippled@g' BUILD.md
 ${SED_COMMAND} -i -E 's@XRPLF/xrpld@XRPLF/rippled@g' BUILD.md
 ${SED_COMMAND} -i -E 's@xrpld \(`xrpld`\)@xrpld@g' BUILD.md
 ${SED_COMMAND} -i -E 's@XRPLF/xrpld@XRPLF/rippled@g' CONTRIBUTING.md
-${SED_COMMAND} -i -E 's@XRPLF/xrpld@XRPLF/rippled@g' docs/build/install.md
+${SED_COMMAND} -i -E 's@XRPLF/xrpld@XRPLF/rippled@g' docs/install.md

 popd
 echo "Processing complete."
--- a/.github/scripts/rename/docs.sh
+++ b/.github/scripts/rename/docs.sh
@@ -77,8 +77,8 @@ ${SED_COMMAND} -i 's/Ripple integrators/XRPL developers/' README.md
 ${SED_COMMAND} -i 's/sanitizer-configuration-for-rippled/sanitizer-configuration-for-xrpld/' docs/build/sanitizers.md
 ${SED_COMMAND} -i 's/rippled/xrpld/g' .github/scripts/levelization/README.md
 ${SED_COMMAND} -i 's/rippled/xrpld/g' .github/scripts/strategy-matrix/generate.py
-${SED_COMMAND} -i 's@/rippled@/xrpld@g' docs/build/install.md
-${SED_COMMAND} -i 's@github.com/XRPLF/xrpld@github.com/XRPLF/rippled@g' docs/build/install.md
+${SED_COMMAND} -i 's@/rippled@/xrpld@g' docs/install.md
+${SED_COMMAND} -i 's@github.com/XRPLF/xrpld@github.com/XRPLF/rippled@g' docs/install.md
 ${SED_COMMAND} -i 's/rippled/xrpld/g' docs/Doxyfile
 ${SED_COMMAND} -i 's/ripple_basics/basics/' include/xrpl/basics/CountedObject.h
 ${SED_COMMAND} -i 's/<ripple/<xrpl/' include/xrpl/protocol/AccountID.h
--- a/.github/scripts/strategy-matrix/generate.py
+++ b/.github/scripts/strategy-matrix/generate.py
@@ -7,7 +7,13 @@ from pathlib import Path

 THIS_DIR = Path(__file__).parent.resolve()

-_BASE_CMAKE_ARGS = ["-Dtests=ON", "-Dwerr=ON", "-Dxrpld=ON", "-Dwextra=ON"]
+_BASE_CMAKE_ARGS = [
+    "-Dtests=ON",
+    "-Dwerr=ON",
+    "-Dxrpld=ON",
+    "-Dwextra=ON",
+    "-Drust=ON",
+]

 # Maps sanitizer names (as used in cmake) to short config-name suffixes.
 _SANITIZER_SUFFIX: dict[str, str] = {
@@ -88,6 +94,9 @@ class PlatformConfig:
    build_only: bool = False  # if true, skip tests (e.g. macos/Windows Debug)
    benchmark: bool = False  # if true, smoke-run the benchmarks after testing
    extra_cmake_args: str = ""
+    # "" is the runner's system compiler, "nix" the flake's CI environment.
+    # macOS only: Linux always builds in a Nix image, Windows has no Nix.
+    toolchain: str = ""

    def __post_init__(self) -> None:
        if isinstance(self.build_type, str):
@@ -137,13 +146,15 @@ class MatrixEntry:
    sanitizers: str
    image: str = ""  # container image; empty for macOS/Windows (runs natively)
    compiler: str = ""  # compiler name ("gcc" or "clang"); empty for macOS/Windows
+    toolchain: str = ""  # "nix" for the flake's CI environment; see PlatformConfig


@dataclasses.dataclass
 class PackagingEntry:
    """One entry in the generated packaging strategy matrix."""

-    artifact_name: str
+    xrpld_artifact_name: str
+    validator_keys_artifact_name: str
    image: str
    distro: str  # e.g. "debian" or "rhel"; drives package-format-specific steps

@@ -214,18 +225,23 @@ def expand_linux_matrix(linux: LinuxFile, minimal: bool) -> list[MatrixEntry]:
 def expand_linux_packaging(linux: LinuxFile) -> list[PackagingEntry]:
    """Generate the packaging matrix from a LinuxFile's package_configs section.

-    Packaging uses vanilla distro images (debian:bookworm, ubi9, …) instead of
+    Packaging uses vanilla distro images (debian:bookworm, almalinux:9) instead of
    the nix-based build images, because deb/rpm tooling (debhelper, rpm-build)
    is taken from the distro's archive rather than from nixpkgs. Each config
    entry carries its own 'image'.
+
+    The artifact names must match what the build job uploads: one artifact per
+    binary, each named after the build config.
    """
    entries = []
    for distro, configs in linux.package_configs.items():
        for cfg in configs:
            for compiler, build_type in itertools.product(cfg.compiler, cfg.build_type):
+                config_name = f"{distro}-{compiler}-{build_type.lower()}-amd64"
                entries.append(
                    PackagingEntry(
-                        artifact_name=f"xrpld-{distro}-{compiler}-{build_type.lower()}-amd64",
+                        xrpld_artifact_name=f"xrpld-{config_name}",
+                        validator_keys_artifact_name=f"validator-keys-{config_name}",
                        image=cfg.image,
                        distro=distro,
                    )
@@ -247,9 +263,12 @@ def expand_platform_matrix(pf: PlatformFile, minimal: bool) -> list[MatrixEntry]
        if minimal and not cfg.minimal:
            continue
        for build_type in cfg.build_type:
+            name = f"{platform_name}-{arch}-{build_type.lower()}"
+            if cfg.toolchain:
+                name += f"-{cfg.toolchain}"
            entries.append(
                MatrixEntry(
-                    config_name=f"{platform_name}-{arch}-{build_type.lower()}",
+                    config_name=name,
                    cmake_args=get_cmake_args(build_type, cfg.extra_cmake_args),
                    cmake_target="install" if is_windows else "all",
                    build_only=cfg.build_only,
@@ -257,6 +276,7 @@ def expand_platform_matrix(pf: PlatformFile, minimal: bool) -> list[MatrixEntry]
                    build_type=build_type,
                    architecture=Architecture(platform=pf.platform, runner=pf.runner),
                    sanitizers="",
+                    toolchain=cfg.toolchain,
                )
            )
    return entries
--- a/.github/scripts/strategy-matrix/linux.json
+++ b/.github/scripts/strategy-matrix/linux.json
@@ -1,5 +1,5 @@
 {
-  "image_tag": "sha-fecfc0c",
+  "image_tag": "sha-a0074f8",
  "configs": {
    "ubuntu": [
      {
@@ -70,7 +70,8 @@
        "compiler": ["gcc"],
        "build_type": ["Release"],
        "arch": ["amd64"],
-        "minimal": false
+        "minimal": false,
+        "extra_cmake_args": "-Dvalidator_keys=ON"
      }
    ],

@@ -79,7 +80,8 @@
        "compiler": ["gcc"],
        "build_type": ["Release"],
        "arch": ["amd64"],
-        "minimal": false
+        "minimal": false,
+        "extra_cmake_args": "-Dvalidator_keys=ON"
      }
    ]
  },
@@ -90,7 +92,7 @@
        "build_type": ["Release"],
        "arch": ["amd64"],
        "minimal": false,
-        "image": "ghcr.io/xrplf/xrpld/packaging-debian:sha-577d745"
+        "image": "ghcr.io/xrplf/xrpld/packaging-debian:sha-a6983f8"
      }
    ],

@@ -100,7 +102,7 @@
        "build_type": ["Release"],
        "arch": ["amd64"],
        "minimal": false,
-        "image": "ghcr.io/xrplf/xrpld/packaging-rhel:sha-577d745"
+        "image": "ghcr.io/xrplf/xrpld/packaging-rhel:sha-a6983f8"
      }
    ]
  }
--- a/.github/scripts/strategy-matrix/macos.json
+++ b/.github/scripts/strategy-matrix/macos.json
@@ -12,6 +12,19 @@
      "extra_cmake_args": "-DCMAKE_POLICY_VERSION_MINIMUM=3.5",
      "build_only": true,
      "minimal": false
+    },
+    {
+      "build_type": "Release",
+      "extra_cmake_args": "-DCMAKE_POLICY_VERSION_MINIMUM=3.5",
+      "toolchain": "nix",
+      "minimal": false
+    },
+    {
+      "build_type": "Debug",
+      "extra_cmake_args": "-DCMAKE_POLICY_VERSION_MINIMUM=3.5",
+      "toolchain": "nix",
+      "build_only": true,
+      "minimal": false
    }
  ]
 }
--- a/.github/workflows/build-packaging-images.yml
+++ b/.github/workflows/build-packaging-images.yml
@@ -36,8 +36,9 @@ jobs:
        distro:
          - name: debian
            base_image: debian:bookworm
+          # AlmaLinux rather than UBI9, which does not ship rpm-sign.
          - name: rhel
-            base_image: registry.access.redhat.com/ubi9/ubi:latest
+            base_image: almalinux:9
    uses: XRPLF/actions/.github/workflows/build-multiarch-image.yml@9e7e4e80af9e684c116b38369add8eea64451f32
    with:
      image_name: xrpld/packaging-${{ matrix.distro.name }}
--- a/.github/workflows/cargo-audit.yml
+++ b/.github/workflows/cargo-audit.yml
@@ -0,0 +1,80 @@
+name: Cargo audit
+
+on:
+  schedule:
+    # 06:32 UTC every Monday.
+    - cron: "32 6 * * 1"
+  push:
+    branches:
+      - "develop"
+      - "release/*"
+    paths:
+      - "crates/**/Cargo.toml"
+      - "crates/Cargo.lock"
+      - ".github/workflows/cargo-audit.yml"
+  pull_request:
+    paths:
+      - "crates/**/Cargo.toml"
+      - "crates/Cargo.lock"
+      - ".github/workflows/cargo-audit.yml"
+  workflow_dispatch:
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+defaults:
+  run:
+    shell: bash
+    working-directory: crates
+
+permissions:
+  contents: read
+
+jobs:
+  audit:
+    runs-on: ubuntu-latest
+    container: ghcr.io/xrplf/xrpld/nix-ubuntu:sha-a0074f8
+    permissions:
+      contents: read
+      # Needed to open an issue on scheduled failures.
+      issues: write
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+
+      - name: Run cargo audit
+        id: audit
+        continue-on-error: true
+        run: |
+          set -o pipefail
+          cargo audit | tee /tmp/cargo-audit.txt
+
+      - name: Prepare issue body
+        if: ${{ steps.audit.outcome != 'success' && github.event_name == 'schedule' }}
+        run: |
+          {
+              echo "## \`cargo audit\` found advisories"
+              echo
+              echo '```'
+              cat /tmp/cargo-audit.txt
+              echo '```'
+              echo
+              echo "---"
+              echo "*This issue was automatically created by the cargo-audit workflow.*"
+          } >/tmp/cargo-audit-issue.md
+
+      - name: Create issue
+        if: ${{ steps.audit.outcome != 'success' && github.event_name == 'schedule' }}
+        uses: XRPLF/actions/create-issue@2b8bc36af85b88bca0dd7bfac2e2dc05f94ad712
+        with:
+          title: "cargo audit found vulnerabilities"
+          body_file: /tmp/cargo-audit-issue.md
+          labels: "Bug,Security"
+
+      - name: Fail if advisories were found
+        if: ${{ steps.audit.outcome != 'success' }}
+        run: |
+          echo "cargo audit found advisories!"
+          cat /tmp/cargo-audit.txt
+          exit 1
--- a/.github/workflows/check-tools.yml
+++ b/.github/workflows/check-tools.yml
@@ -79,7 +79,7 @@ jobs:
        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1

      - name: Prepare runner
-        uses: XRPLF/actions/prepare-runner@c00c22ada3bd6bcda48fcb0d62fbbab49fec8a0f
+        uses: XRPLF/actions/prepare-runner@51af40f99ea91a08c3528ddf16d98132dcc7e63c
        with:
          enable_ccache: false

--- a/.github/workflows/on-pr.yml
+++ b/.github/workflows/on-pr.yml
@@ -79,24 +79,28 @@ jobs:

            # Keep the paths below in sync with those in `on-trigger.yml`.
            .github/actions/build-deps/**
-            .github/actions/generate-version/**
+            .github/actions/release-info/**
            .github/actions/setup-conan/**
+            .github/actions/setup-nix-env/**
            .github/scripts/strategy-matrix/**
            .github/workflows/reusable-build-test-config.yml
            .github/workflows/reusable-build-test.yml
            .github/workflows/reusable-check-autogen.yml
            .github/workflows/reusable-clang-tidy.yml
            .github/workflows/reusable-package.yml
+            .github/workflows/reusable-rust.yml
            .github/workflows/reusable-strategy-matrix.yml
            .github/workflows/reusable-test.yml
            .github/workflows/reusable-upload-recipe.yml
            .clang-tidy
            .codecov.yml
+            bin/check-nix-store-refs.sh
            bin/check-tools.sh
            bin/default-loader-path.sh
            cfg/**
            cmake/**
            conan/**
+            crates/**
            external/**
            include/**
            src/**
@@ -104,6 +108,9 @@ jobs:
            CMakeLists.txt
            conanfile.py
            conan.lock
+            flake.lock
+            flake.nix
+            nix/**
            LICENSE.md
            package/**
            README.md
@@ -175,6 +182,13 @@ jobs:
    secrets:
      CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}

+  rust:
+    needs: should-run
+    if: ${{ needs.should-run.outputs.go == 'true' }}
+    uses: ./.github/workflows/reusable-rust.yml
+    secrets:
+      CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
+
  package:
    needs: [should-run, build-test]
    # Packaging consumes the debian/rhel release binaries, which are only built
@@ -219,6 +233,7 @@ jobs:
      - check-rename
      - clang-tidy
      - build-test
+      - rust
      - package
      - upload-recipe
      - notify-clio
--- a/.github/workflows/on-tag.yml
+++ b/.github/workflows/on-tag.yml
@@ -1,5 +1,9 @@
-# This workflow uploads the libxrpl recipe to the Conan remote and builds
-# release packages when a versioned tag is pushed.
+# When a versioned tag is pushed, this workflow:
+#
+#   - uploads the libxrpl recipe to the Conan remote
+#   - builds and tests the release binaries
+#   - builds the DEB and RPM packages
+#   - publishes those packages to the XRPLF package repositories
 name: Tag

 on:
@@ -24,7 +28,7 @@ jobs:
      remote_password: ${{ secrets.NEXUS_REMOTE_PASSWORD }}

  build-test:
-    if: ${{ github.repository == 'XRPLF/rippled' }}
+    if: ${{ github.repository_owner == 'XRPLF' }}
    uses: ./.github/workflows/reusable-build-test.yml
    strategy:
      fail-fast: true
@@ -37,6 +41,12 @@ jobs:
      CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}

  package:
-    if: ${{ github.repository == 'XRPLF/rippled' }}
+    if: ${{ github.repository_owner == 'XRPLF' }}
    needs: build-test
    uses: ./.github/workflows/reusable-package.yml
+    with:
+      publish: true
+    secrets:
+      remote_username: ${{ secrets.NEXUS_REMOTE_USERNAME }}
+      remote_password: ${{ secrets.NEXUS_REMOTE_PASSWORD }}
+      signing_key: ${{ secrets.NEXUS_PACKAGES_PRIVATE_KEY }}
--- a/.github/workflows/on-trigger.yml
+++ b/.github/workflows/on-trigger.yml
@@ -15,24 +15,28 @@ on:

      # Keep the paths below in sync with those in `on-pr.yml`.
      - ".github/actions/build-deps/**"
-      - ".github/actions/generate-version/**"
+      - ".github/actions/release-info/**"
      - ".github/actions/setup-conan/**"
+      - ".github/actions/setup-nix-env/**"
      - ".github/scripts/strategy-matrix/**"
      - ".github/workflows/reusable-build-test-config.yml"
      - ".github/workflows/reusable-build-test.yml"
      - ".github/workflows/reusable-check-autogen.yml"
      - ".github/workflows/reusable-clang-tidy.yml"
      - ".github/workflows/reusable-package.yml"
+      - ".github/workflows/reusable-rust.yml"
      - ".github/workflows/reusable-strategy-matrix.yml"
      - ".github/workflows/reusable-test.yml"
      - ".github/workflows/reusable-upload-recipe.yml"
      - ".clang-tidy"
      - ".codecov.yml"
+      - "bin/check-nix-store-refs.sh"
      - "bin/check-tools.sh"
      - "bin/default-loader-path.sh"
      - "cfg/**"
      - "cmake/**"
      - "conan/**"
+      - "crates/**"
      - "external/**"
      - "include/**"
      - "src/**"
@@ -40,6 +44,9 @@ on:
      - "CMakeLists.txt"
      - "conanfile.py"
      - "conan.lock"
+      - "flake.lock"
+      - "flake.nix"
+      - "nix/**"
      - "LICENSE.md"
      - "package/**"
      - "README.md"
@@ -96,6 +103,11 @@ jobs:
    secrets:
      CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}

+  rust:
+    uses: ./.github/workflows/reusable-rust.yml
+    secrets:
+      CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
+
  upload-recipe:
    needs: build-test
    # Only run when pushing to the develop branch.
@@ -108,3 +120,11 @@ jobs:
  package:
    needs: build-test
    uses: ./.github/workflows/reusable-package.yml
+    with:
+      # Packages are built on every trigger; only develop pushes in XRPLF/rippled
+      # publish them, matching upload-recipe above.
+      publish: ${{ github.repository == 'XRPLF/rippled' && github.event_name == 'push' && github.ref == 'refs/heads/develop' }}
+    secrets:
+      remote_username: ${{ secrets.NEXUS_REMOTE_USERNAME }}
+      remote_password: ${{ secrets.NEXUS_REMOTE_PASSWORD }}
+      signing_key: ${{ secrets.NEXUS_PACKAGES_PRIVATE_KEY }}
--- a/.github/workflows/publish-docs.yml
+++ b/.github/workflows/publish-docs.yml
@@ -41,13 +41,13 @@ env:
 jobs:
  build:
    runs-on: ubuntu-latest
-    container: ghcr.io/xrplf/xrpld/nix-ubuntu:sha-fecfc0c
+    container: ghcr.io/xrplf/xrpld/nix-ubuntu:sha-a0074f8
    steps:
      - name: Checkout repository
        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1

      - name: Prepare runner
-        uses: XRPLF/actions/prepare-runner@c00c22ada3bd6bcda48fcb0d62fbbab49fec8a0f
+        uses: XRPLF/actions/prepare-runner@51af40f99ea91a08c3528ddf16d98132dcc7e63c
        with:
          enable_ccache: false

--- a/.github/workflows/reusable-build-test-config.yml
+++ b/.github/workflows/reusable-build-test-config.yml
@@ -69,6 +69,12 @@ on:
        type: string
        default: ""

+      toolchain:
+        description: 'Where the toolchain comes from ("nix" to build the flake CI environment on the runner, empty for the system one). macOS only: Linux always builds in a Nix image, and Nix has no Windows support.'
+        required: false
+        type: string
+        default: ""
+
    secrets:
      CODECOV_TOKEN:
        description: "The Codecov token to use for uploading coverage reports."
@@ -106,10 +112,14 @@ jobs:
      # header files are copied into separate directories by CMake, which will
      # otherwise result in cache misses.
      CCACHE_SLOPPINESS: include_file_ctime,include_file_mtime
-      # Determine if coverage and voidstar should be enabled.
+      # Determine if coverage, voidstar and validator-keys should be enabled.
      COVERAGE_ENABLED: ${{ contains(inputs.cmake_args, '-Dcoverage=ON') }}
      VOIDSTAR_ENABLED: ${{ contains(inputs.cmake_args, '-Dvoidstar=ON') }}
+      VALIDATOR_KEYS_ENABLED: ${{ contains(inputs.cmake_args, '-Dvalidator_keys=ON') }}
      SANITIZERS_ENABLED: ${{ inputs.sanitizers != '' }}
+      # The binaries reusable-package.yml consumes. A private repository skips
+      # them except on a tag push, which is what produces its release packages.
+      PACKAGING_ARTIFACTS_ENABLED: ${{ github.event.repository.visibility == 'public' || startsWith(github.ref, 'refs/tags/') }}
    steps:
      - name: Cleanup workspace (macOS and Windows)
        if: ${{ runner.os == 'macOS' || runner.os == 'Windows' }}
@@ -119,10 +129,15 @@ jobs:
        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1

      - name: Prepare runner
-        uses: XRPLF/actions/prepare-runner@c00c22ada3bd6bcda48fcb0d62fbbab49fec8a0f
+        uses: XRPLF/actions/prepare-runner@51af40f99ea91a08c3528ddf16d98132dcc7e63c
        with:
          enable_ccache: ${{ inputs.ccache_enabled }}

+      # Before any step that uses a build tool, composite actions included.
+      - name: Setup Nix environment
+        if: ${{ inputs.toolchain == 'nix' }}
+        uses: ./.github/actions/setup-nix-env
+
      - name: Set ccache log file
        if: ${{ inputs.ccache_enabled && runner.debug == '1' }}
        run: echo "CCACHE_LOGFILE=${{ runner.temp }}/ccache.log" >>"${GITHUB_ENV}"
@@ -147,7 +162,22 @@ jobs:
        with:
          compiler: ${{ inputs.compiler }}

+      - name: Use cargo artifacts cache
+        uses: Swatinem/rust-cache@6323deb102c322ba6fcbdcafc7e3dddab59af2b6 # v2.9.2
+        with:
+          cache-directories: ${{ env.BUILD_DIR }}/corrosion
+          key: ${{ inputs.config_name }}
+          save-if: ${{ github.ref == 'refs/heads/develop' || startsWith(github.ref, 'refs/heads/release') }}
+          # two workspaces here because build artifacts are located in 2 places:
+          # - crates/target when cargo is called directly
+          # - build/cargo when cargo is called by cmake
+          workspaces: |
+            crates
+            crates -> ${{ runner.os == 'Windows' && format('../{0}/x64/{1}/cargo', env.BUILD_DIR, inputs.build_type) || format('../{0}/cargo', env.BUILD_DIR) }}
+
+      # `setup-nix-env` already did this for the Nix toolchain.
      - name: Setup Conan
+        if: ${{ inputs.toolchain != 'nix' }}
        env:
          SANITIZERS: ${{ inputs.sanitizers }}
        uses: ./.github/actions/setup-conan
@@ -211,6 +241,24 @@ jobs:
              --target "${CMAKE_TARGET}" \
              2>&1 | tee "${GITHUB_WORKSPACE}/build.log"

+      # Nothing may reference the store, so whole trees are checked - the Conan
+      # cache included, since what it holds is what gets uploaded and reused.
+      - name: Check the build output for Nix store references (Nix toolchain)
+        if: ${{ inputs.toolchain == 'nix' }}
+        run: ./bin/check-nix-store-refs.sh "${BUILD_DIR}"
+
+      - name: Check the Conan cache for Nix store references (Nix toolchain)
+        if: ${{ inputs.toolchain == 'nix' }}
+        run: ./bin/check-nix-store-refs.sh "${CONAN_HOME}"
+
+      # Only what PatchNixBinary.cmake retargets: the toolchain in the Linux
+      # images always references the store. Same condition it uses.
+      - name: Check for Nix store references (Linux)
+        if: ${{ runner.os == 'Linux' && env.SANITIZERS_ENABLED == 'false' }}
+        run: |
+          ./bin/check-nix-store-refs.sh "${BUILD_DIR}/xrpld"
+          ./bin/check-nix-store-refs.sh "${BUILD_DIR}/xrpl_tests"
+
      - name: Show ccache statistics
        if: ${{ inputs.ccache_enabled }}
        run: |
@@ -221,7 +269,7 @@ jobs:
          fi

      - name: Upload the binary (Linux)
-        if: ${{ github.event.repository.visibility == 'public' && runner.os == 'Linux' }}
+        if: ${{ env.PACKAGING_ARTIFACTS_ENABLED == 'true' && runner.os == 'Linux' }}
        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
        with:
          name: xrpld-${{ inputs.config_name }}
@@ -229,6 +277,22 @@ jobs:
          retention-days: 3
          if-no-files-found: error

+      - name: Run the validator-keys tests
+        if: ${{ env.VALIDATOR_KEYS_ENABLED == 'true' }}
+        working-directory: ${{ env.BUILD_DIR }}
+        run: ./validator-keys --unittest
+
+      - name: Upload the validator-keys binary
+        if: ${{ env.PACKAGING_ARTIFACTS_ENABLED == 'true' && env.VALIDATOR_KEYS_ENABLED == 'true' }}
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
+        with:
+          name: validator-keys-${{ inputs.config_name }}
+          path: |
+            ${{ env.BUILD_DIR }}/validator-keys
+            ${{ env.BUILD_DIR }}/validator-keys-LICENSE
+          retention-days: 3
+          if-no-files-found: error
+
      - name: Upload the test binary (Linux)
        if: ${{ github.event.repository.visibility == 'public' && runner.os == 'Linux' }}
        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
@@ -306,6 +370,11 @@ jobs:

          LD_PRELOAD="$PRELOAD" ./xrpld --unittest --unittest-jobs "${BUILD_NPROC}" 2>&1 | tee "${GITHUB_WORKSPACE}/unittest.log"

+      - name: Run Rust tests
+        if: ${{ !inputs.build_only }}
+        working-directory: crates
+        run: cargo nextest run --workspace --all-features --locked --no-tests=warn
+
      # Smoke-run every benchmark module with a single repetition to confirm the
      # benchmarks still build and execute. This is a correctness check, not a
      # performance measurement, so there is nothing to gain from repeating it
@@ -370,13 +439,14 @@ jobs:
              --target coverage

      - name: Upload coverage report
-        if: ${{ github.repository == 'XRPLF/rippled' && !inputs.build_only && env.COVERAGE_ENABLED == 'true' }}
+        if: ${{ github.repository_owner == 'XRPLF' && !inputs.build_only && env.COVERAGE_ENABLED == 'true' }}
        uses: codecov/codecov-action@fb8b3582c8e4def4969c97caa2f19720cb33a72f # v7.0.0
        with:
          disable_search: true
          disable_telem: true
          fail_ci_if_error: true
          files: ${{ env.BUILD_DIR }}/coverage.xml
+          flags: cpp
          plugins: noop
          token: ${{ secrets.CODECOV_TOKEN }}
          verbose: true
--- a/.github/workflows/reusable-build-test.yml
+++ b/.github/workflows/reusable-build-test.yml
@@ -51,5 +51,6 @@ jobs:
      config_name: ${{ matrix.config_name }}
      sanitizers: ${{ matrix.sanitizers }}
      compiler: ${{ matrix.compiler || '' }}
+      toolchain: ${{ matrix.toolchain || '' }}
    secrets:
      CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
--- a/.github/workflows/reusable-clang-tidy.yml
+++ b/.github/workflows/reusable-clang-tidy.yml
@@ -34,7 +34,7 @@ jobs:
    needs: [determine-files]
    if: ${{ needs.determine-files.outputs.cpp_changed_files != '' || needs.determine-files.outputs.need_full_run == 'true' }}
    runs-on: ["self-hosted", "Linux", "X64", "heavy"]
-    container: "ghcr.io/xrplf/xrpld/nix-debian:sha-fecfc0c"
+    container: "ghcr.io/xrplf/xrpld/nix-debian:sha-a0074f8"
    permissions:
      contents: read
      issues: write
@@ -43,7 +43,7 @@ jobs:
        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1

      - name: Prepare runner
-        uses: XRPLF/actions/prepare-runner@c00c22ada3bd6bcda48fcb0d62fbbab49fec8a0f
+        uses: XRPLF/actions/prepare-runner@51af40f99ea91a08c3528ddf16d98132dcc7e63c
        with:
          enable_ccache: false

@@ -59,6 +59,13 @@ jobs:
        with:
          compiler: ${{ env.COMPILER }}

+      - name: Use cargo artifacts cache
+        uses: Swatinem/rust-cache@6323deb102c322ba6fcbdcafc7e3dddab59af2b6 # v2.9.2
+        with:
+          cache-directories: ${{ env.BUILD_DIR }}/corrosion
+          save-if: ${{ github.ref == 'refs/heads/develop' || startsWith(github.ref, 'refs/heads/release') }}
+          workspaces: crates -> ../${{ env.BUILD_DIR }}/cargo
+
      - name: Setup Conan
        uses: ./.github/actions/setup-conan

@@ -80,13 +87,13 @@ jobs:
              -Dwerr=ON \
              -Dxrpld=ON \
              -Dverify_headers=ON \
+              -Drust=ON \
              ..

-      # clang-tidy needs headers generated from proto files
-      - name: Build libxrpl.libpb
+      - name: Build clang-tidy prerequisites
        working-directory: ${{ env.BUILD_DIR }}
        run: |
-          ninja -j ${{ steps.nproc.outputs.nproc }} xrpl.libpb
+          ninja -j ${{ steps.nproc.outputs.nproc }} tidy_prerequisites

      - name: Run clang tidy
        id: run_clang_tidy
--- a/.github/workflows/reusable-package.yml
+++ b/.github/workflows/reusable-package.yml
@@ -1,17 +1,37 @@
-# Build Linux packages (DEB and RPM) from pre-built binary artifacts.
-# Discovers which configurations to package from linux.json (configs in
-# "package_configs") and fans out one job per distro. Only linux/amd64 is
-# supported; the runner is hardcoded in the job below.
+# Build Linux packages from the pre-built xrpld and validator-keys artifacts:
+#
+#   - one job per distro, taken from "package_configs" in linux.json
+#   - each job runs in that distro's container, which is what decides DEB or RPM
+#   - with 'publish: true' a job also uploads what it built
+#     (see package/publish_pkg.sh)
+#
+# Only linux/amd64 is supported; the runner is hardcoded in the job below.
 name: Package

 on:
  workflow_call:
    inputs:
-      pkg_release:
-        description: "Package release number. Increment when repackaging the same executable."
+      publish:
+        description: "Whether to publish the packages after building them."
+        required: false
+        type: boolean
+        default: false
+      nexus_url:
+        description: "The base URL of the Nexus instance hosting the deb and rpm repositories."
        required: false
        type: string
-        default: "1"
+        default: https://packages.xrplf.org
+
+    secrets:
+      remote_username:
+        description: "The username of a Nexus account with write access to the repositories."
+        required: false
+      remote_password:
+        description: "The password or token for that Nexus account."
+        required: false
+      signing_key:
+        description: "Armoured PGP private key used to sign the RPMs. Required when publishing."
+        required: false

 defaults:
  run:
@@ -41,11 +61,11 @@ jobs:

  package:
    needs: [generate-matrix]
-    if: ${{ github.event.repository.visibility == 'public' }}
+    if: ${{ github.event.repository.visibility == 'public' || startsWith(github.ref, 'refs/tags/') }}
    strategy:
      fail-fast: false
      matrix: ${{ fromJson(needs.generate-matrix.outputs.matrix) }}
-    name: "${{ matrix.artifact_name }}"
+    name: "${{ matrix.xrpld_artifact_name }}"
    permissions:
      contents: read
    runs-on: ["self-hosted", "Linux", "X64", "heavy"]
@@ -56,26 +76,54 @@ jobs:
      - name: Checkout repository
        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1

-      - name: Download pre-built binary
+      - name: Download pre-built xrpld binary
        uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1
        with:
-          name: ${{ matrix.artifact_name }}
+          name: ${{ matrix.xrpld_artifact_name }}
          path: ${{ env.BUILD_DIR }}

-      - name: Make binary executable
-        run: chmod +x "${BUILD_DIR}/xrpld"
+      - name: Download pre-built validator-keys binary
+        uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1
+        with:
+          name: ${{ matrix.validator_keys_artifact_name }}
+          path: ${{ env.BUILD_DIR }}
+
+      - name: Make binaries executable
+        run: chmod +x "${BUILD_DIR}/xrpld" "${BUILD_DIR}/validator-keys"
+
+      - name: Determine release info
+        id: release_info
+        uses: ./.github/actions/release-info

      - name: Build package
        env:
-          PKG_RELEASE: ${{ inputs.pkg_release }}
+          PKG_RELEASE: ${{ steps.release_info.outputs.pkg_release }}
+          PKG_CHANNEL: ${{ steps.release_info.outputs.channel }}
        run: ./package/build_pkg.sh

+      # Before the upload, so the artifact and the published package are the
+      # same bytes. DEBs are not signed, so the key is never set on that job.
+      - name: Sign RPM
+        if: ${{ inputs.publish && matrix.distro == 'rhel' }}
+        env:
+          PKG_SIGNING_KEY: ${{ secrets.signing_key }}
+        run: ./package/sign_rpm.sh "${BUILD_DIR}"
+
      - name: Upload package artifact
        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
        with:
-          name: ${{ matrix.artifact_name }}-pkg
+          name: ${{ matrix.xrpld_artifact_name }}-pkg
          path: |
            ${{ env.BUILD_DIR }}/debbuild/*.deb
            ${{ env.BUILD_DIR }}/debbuild/*.ddeb
            ${{ env.BUILD_DIR }}/rpmbuild/RPMS/**/*.rpm
          if-no-files-found: error
+
+      - name: Publish package
+        if: ${{ inputs.publish }}
+        env:
+          CHANNEL: ${{ steps.release_info.outputs.channel }}
+          NEXUS_URL: ${{ inputs.nexus_url }}
+          NEXUS_USERNAME: ${{ secrets.remote_username }}
+          NEXUS_PASSWORD: ${{ secrets.remote_password }}
+        run: ./package/publish_pkg.sh "${CHANNEL}" "${BUILD_DIR}"
--- a/.github/workflows/reusable-rust.yml
+++ b/.github/workflows/reusable-rust.yml
@@ -0,0 +1,86 @@
+# Clippy, coverage and documentation for the Rust crates in crates/. Each runs
+# as an independent job on a GitHub-hosted runner, but inside the same container
+# image used to build the crates in the C++/Corrosion path, so the toolchain
+# (and therefore the lints, coverage instrumentation and the cargo cache) matches
+# what production builds use.
+#
+# Rust unit tests are deliberately NOT run here. They run as part of the C++
+# build (reusable-build-test-config.yml), which already compiles the crates on a
+# self-hosted runner, so there is no need to provision a toolchain again.
+name: Rust
+
+on:
+  workflow_call:
+    secrets:
+      CODECOV_TOKEN:
+        description: "The Codecov token to use for uploading coverage reports."
+        required: true
+
+defaults:
+  run:
+    shell: bash
+    working-directory: crates
+
+permissions:
+  contents: read
+
+jobs:
+  clippy:
+    runs-on: ubuntu-latest
+    container: ghcr.io/xrplf/xrpld/nix-ubuntu:sha-a0074f8
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+
+      - name: Use cargo artifacts cache
+        uses: Swatinem/rust-cache@6323deb102c322ba6fcbdcafc7e3dddab59af2b6 # v2.9.2
+        with:
+          workspaces: crates
+
+      - name: Run clippy
+        run: cargo clippy --workspace --all-targets --all-features --locked -- -D warnings
+
+  coverage:
+    runs-on: ubuntu-latest
+    container: ghcr.io/xrplf/xrpld/nix-ubuntu:sha-a0074f8
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+
+      - name: Use cargo artifacts cache
+        uses: Swatinem/rust-cache@6323deb102c322ba6fcbdcafc7e3dddab59af2b6 # v2.9.2
+        with:
+          workspaces: crates
+
+      - name: Generate coverage report
+        run: cargo llvm-cov nextest --workspace --all-features --locked --no-tests=warn --lcov --output-path lcov.info
+
+      - name: Upload coverage report
+        if: ${{ github.repository == 'XRPLF/rippled' }}
+        uses: codecov/codecov-action@fb8b3582c8e4def4969c97caa2f19720cb33a72f # v7.0.0
+        with:
+          disable_search: true
+          disable_telem: true
+          fail_ci_if_error: true
+          files: crates/lcov.info
+          flags: rust
+          plugins: noop
+          token: ${{ secrets.CODECOV_TOKEN }}
+          verbose: true
+
+  doc:
+    runs-on: ubuntu-latest
+    container: ghcr.io/xrplf/xrpld/nix-ubuntu:sha-a0074f8
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+
+      - name: Use cargo artifacts cache
+        uses: Swatinem/rust-cache@6323deb102c322ba6fcbdcafc7e3dddab59af2b6 # v2.9.2
+        with:
+          workspaces: crates
+
+      - name: Build documentation
+        env:
+          RUSTDOCFLAGS: "-D warnings"
+        run: cargo doc --workspace --no-deps --all-features --locked
--- a/.github/workflows/reusable-upload-recipe.yml
+++ b/.github/workflows/reusable-upload-recipe.yml
@@ -40,7 +40,7 @@ defaults:
 jobs:
  upload:
    runs-on: ubuntu-latest
-    container: ghcr.io/xrplf/xrpld/nix-ubuntu:sha-fecfc0c
+    container: ghcr.io/xrplf/xrpld/nix-ubuntu:sha-a0074f8
    env:
      REMOTE_NAME: ${{ inputs.remote_name }}
      CONAN_LOGIN_USERNAME_XRPLF: ${{ secrets.remote_username }}
@@ -49,9 +49,9 @@ jobs:
      - name: Checkout repository
        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1

-      - name: Generate build version number
-        id: version
-        uses: ./.github/actions/generate-version
+      - name: Determine release info
+        id: release_info
+        uses: ./.github/actions/release-info

      - name: Set up Conan
        uses: ./.github/actions/setup-conan
@@ -64,8 +64,8 @@ jobs:

      - name: Upload Conan recipe (version)
        run: |
-          conan export . --version=${{ steps.version.outputs.version }}
-          conan upload --confirm --check --remote="${REMOTE_NAME}" xrpl/${{ steps.version.outputs.version }}
+          conan export . --version=${{ steps.release_info.outputs.version }}
+          conan upload --confirm --check --remote="${REMOTE_NAME}" xrpl/${{ steps.release_info.outputs.version }}

      # When this workflow is triggered by a push event, it will always be when merging into the
      # 'develop' branch, see on-trigger.yml.
@@ -92,4 +92,4 @@ jobs:
          conan upload --confirm --check --remote="${REMOTE_NAME}" xrpl/release

    outputs:
-      ref: xrpl/${{ steps.version.outputs.version }}
+      ref: xrpl/${{ steps.release_info.outputs.version }}
--- a/.github/workflows/upload-conan-deps.yml
+++ b/.github/workflows/upload-conan-deps.yml
@@ -72,6 +72,11 @@ jobs:
        with:
          enable_ccache: false

+      # Before any step that uses a build tool, composite actions included.
+      - name: Setup Nix environment
+        if: ${{ matrix.toolchain == 'nix' }}
+        uses: ./.github/actions/setup-nix-env
+
      - name: Print build environment
        uses: XRPLF/actions/print-build-env@59dec886e4afb05a1724443af08baccbc045b574

@@ -87,7 +92,9 @@ jobs:
        with:
          compiler: ${{ matrix.compiler }}

+      # `setup-nix-env` already did this for the Nix toolchain.
      - name: Setup Conan
+        if: ${{ matrix.toolchain != 'nix' }}
        env:
          SANITIZERS: ${{ matrix.sanitizers }}
        uses: ./.github/actions/setup-conan
@@ -106,6 +113,10 @@ jobs:
          log_verbosity: ${{ runner.os == 'Windows' && 'quiet' || 'verbose' }}
          sanitizers: ${{ matrix.sanitizers }}

+      - name: Check the Conan cache for Nix store references (Nix toolchain)
+        if: ${{ matrix.toolchain == 'nix' }}
+        run: ./bin/check-nix-store-refs.sh "${CONAN_HOME}"
+
      - name: Log into Conan remote
        if: ${{ github.repository == 'XRPLF/rippled' && (github.event_name == 'push' || github.event_name == 'workflow_dispatch') }}
        run: conan remote login "${CONAN_REMOTE_NAME}" "${{ secrets.NEXUS_REMOTE_USERNAME }}" --password "${{ secrets.NEXUS_REMOTE_PASSWORD }}"
--- a/.gitignore
+++ b/.gitignore
@@ -90,5 +90,8 @@ target/
 # clangd cache
 /.cache

+# Rust build directory
+crates/target
+
 # Env. file carrying environmental setup data for local or cloud runs.
 .env.*
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -62,6 +62,15 @@ repos:
        types_or: [c++, c, proto]
        exclude: ^include/xrpl/protocol_autogen/(transactions|ledger_entries)/

+  - repo: local
+    hooks:
+      - id: cargo-fmt
+        name: cargo fmt
+        entry: cargo fmt --manifest-path crates/Cargo.toml --all
+        language: system
+        types: [rust]
+        pass_filenames: false # rustfmt formats the whole workspace
+
  - repo: https://github.com/BlankSpruce/gersemi-pre-commit
    rev: e98930bdc210d3387007f9252d8c1694ea7e410f # frozen: 0.27.7
    hooks:
--- a/API-CHANGELOG.md
+++ b/API-CHANGELOG.md
@@ -42,6 +42,7 @@ This section contains changes targeting a future version.

 ### Bugfixes

+- `get_aggregate_price`: Duplicate entries in the `oracles` request array are now ignored. [#6586](https://github.com/XRPLF/rippled/pull/6586)
 - Peer Crawler: The `port` field in `overlay.active[]` now consistently returns an integer instead of a string for outbound peers. [#6318](https://github.com/XRPLF/rippled/pull/6318)
 - `ping`: The `ip` field is no longer returned as an empty string for proxied connections without a forwarded-for header. It is now omitted, consistent with the behavior for identified connections. [#6730](https://github.com/XRPLF/rippled/pull/6730)
 - gRPC `GetLedgerDiff`: Fixed error message that incorrectly said "base ledger not validated" when the desired ledger was not validated. [#6730](https://github.com/XRPLF/rippled/pull/6730)
@@ -53,6 +54,8 @@ This section contains changes targeting a future version.
 - `submit`: The `fail_hard` field now returns an error if the value is not a boolean. [#6529](https://github.com/XRPLF/rippled/pull/6529)
 - `subscribe`: The `taker` field in the `books` array now returns `actMalformed` instead of `badIssuer` if the value is not a valid account. [#6529](https://github.com/XRPLF/rippled/pull/6529)
 - Fixed a bug in `Forwarded` HTTP header parsing where the extracted IP address could be incorrect when no comma or semicolon delimiter follows the address. This could cause the server to misidentify a client's IP address when operating behind a reverse proxy. [#6529](https://github.com/XRPLF/rippled/pull/6529)
+- `gateway_balances`: The `account` and `ident` fields now return an `invalidParams` error if the value is not a string, instead of an `internal` error. [#7655](https://github.com/XRPLF/rippled/pull/7655)
+- `account_lines`: The `peer` field now returns an error if the value is not a string. [#7728](https://github.com/XRPLF/rippled/pull/7728)

 ## XRP Ledger server version 3.1.0

--- a/BUILD.md
+++ b/BUILD.md
@@ -4,34 +4,14 @@

 ## Minimum Requirements

-See [System Requirements](https://xrpl.org/system-requirements.html).
+For the hardware needed to run a node, see
+[System Requirements](https://xrpl.org/system-requirements.html).

-Building xrpld generally requires Git, Python, Conan, CMake, and a C++
-compiler.
-
- [Python](https://www.python.org/downloads/)
- [Conan](https://conan.io/downloads.html)
- [CMake](https://cmake.org/download/)
-
-You can verify that the required tools are installed and runnable with:
-
-```bash
-./bin/check-tools.sh
-```
-
-`xrpld` is written in the C++23 dialect. The [tested compiler versions][cpp23-support] are:
-
-| Compiler    | Version         |
-| ----------- | --------------- |
-| GCC         | 15.2            |
-| Clang       | 22              |
-| Apple Clang | 21              |
-| MSVC        | 19.44[^windows] |
+For the software needed to build xrpld, see the
+[environment setup guide](./docs/build/environment.md).

 ## Operating Systems

-Please see the [environment setup guide](./docs/build/environment.md) for detailed instructions for all platforms.
-
 ### Linux

 The Ubuntu Linux distribution has received the highest level of quality
@@ -47,9 +27,8 @@ CI testing is done in macOS 26 (Tahoe), but the build defaults `CMAKE_OSX_DEPLOY

 ### Windows

-Windows is used by some engineers for development only.
-
-[^windows]: Windows is not recommended for production use.
+Windows is used by some engineers for development only, and is not recommended
+for production use.

 ## Steps

@@ -74,37 +53,25 @@ releases](https://github.com/XRPLF/rippled/releases).

 ### Set Up Conan

-After you have a [C++ development environment](./docs/build/environment.md) ready with Git, Python,
-Conan, CMake, and a C++ compiler, you may need to set up your Conan profile.
-
-These instructions assume a basic familiarity with Conan and CMake. If you are
-unfamiliar with Conan, then please read [this crash course](./docs/build/conan.md) or the official
-[Getting Started][conan-getting-started] walkthrough.
-
-#### Profiles
-
-We recommend that you install our Conan profiles:
+Once your [development environment](./docs/build/environment.md) is ready, set
+Conan up for this repository:

 ```bash
-conan config install conan/profiles/ -tf $(conan config home)/profiles/
+./conan/init.sh
 ```

-You can check your Conan profile by running:
+That installs our [`global.conf`](./conan/global.conf), our Conan
+[profiles](./conan/profiles), and the `xrplf` remote that hosts some of our
+dependencies. It honours `CONAN_HOME` and never deletes an existing Conan home,
+so it is safe to re-run — it only overwrites the files it manages.

-```bash
-conan profile show
-```
+> [!TIP]
+> In the [Nix development shell](./docs/build/nix.md#conan-configuration) this is
+> already done for you: the script runs on entry.

-If the default profile is not suitable for your environment, you can create a custom profile and pass it to Conan.
-More information on customizing Conan can be found in the [Advanced Conan configuration](./docs/build/advanced_conan.md).
-
-#### Add xrplf remote
-
-Run the following command to add the `xrplf` remote, which hosts some of our dependencies:
-
-```bash
-conan remote add --index 0 --force xrplf https://conan.xrplf.org/repository/conan/
-```
+You can inspect the resulting profile with `conan profile show`. If it is not
+suitable for your environment, create a custom profile and pass it to Conan — see
+[Advanced Conan configuration](./docs/build/advanced_conan.md).

 ### Set Up Ccache

@@ -269,10 +236,14 @@ which is only enabled when the `coverage` option is set, e.g. with
 Prerequisites for the coverage report:

 - [gcovr tool][gcovr] (can be installed e.g. with [pip][python-pip])
- `gcov` for GCC (installed with the compiler by default) or
- `llvm-cov` for Clang (installed with the compiler by default)
+- `gcov` for GCC or `llvm-cov` for Clang, usually installed with the compiler
 - `Debug` build type

+> [!NOTE]
+> Clang coverage is not available in the [Nix development shell](./docs/build/nix.md#building-xrpld-in-the-nix-shell):
+> its `clang` shells do not ship `llvm-cov`. Use a `gcc` shell instead (`.#gcc`,
+> or `.#gcc-plain` on Linux), which provides a `gcov` matching its compiler.
+
 A coverage report is created when the following steps are completed, in order:

 1. `xrpld` binary built with instrumentation data, enabled by the `coverage`
@@ -333,6 +304,7 @@ See [Sanitizers docs](./docs/build/sanitizers.md) for more details.
 | ---------------- | ------------- | ----------------------------------------------------------------------------- |
 | `assert`         | OFF           | Force enabling assertions.                                                    |
 | `coverage`       | OFF           | Prepare the coverage report.                                                  |
+| `rust`           | OFF           | Build the Rust crates and the C++ code that depends on them.                  |
 | `tests`          | OFF           | Build tests.                                                                  |
 | `unity`          | OFF           | Configure a unity build.                                                      |
 | `verify_headers` | ON            | Make the `verify-headers` target available to compile each header on its own. |
@@ -345,6 +317,30 @@ memory) since they concatenate sources into fewer translation units. Non-unity
 builds may be faster for incremental builds, and can be helpful for detecting
 `#include` omissions.

+### Rust crates
+
+The Rust crates in `crates/` are only part of the build when `rust` is ON. With
+`-Drust=OFF` (the default) the `crates` directory is not added to the build, no
+cxxbridge bindings are generated, and the C++ tests that exercise the Rust
+interop are not compiled — so no Rust toolchain is needed. CI builds always pass
+`-Drust=ON`.
+
+With `-Drust=ON` you need one extra dependency: a Rust toolchain (`cargo`,
+`rustc`) matching the channel pinned in
+[`rust-toolchain.toml`](./rust-toolchain.toml), which compiles the crates and
+generates the cxxbridge bindings. It is provided by the
+[Nix development shell](./docs/build/nix.md), so `-Drust=ON` works there without
+any extra setup; otherwise install it as described in
+[Rust](./docs/build/environment.md#rust).
+
+The crates also have their own Rust unit tests. Those are run with `cargo` and
+need only the Rust toolchain, independently of CMake and of the `rust` option
+(CI runs them with `cargo nextest`):
+
+```bash
+cargo test --manifest-path crates/Cargo.toml --workspace
+```
+
 ### Verifying headers

 The regular build only compiles `.cpp` files, so a header is only ever checked
@@ -389,10 +385,14 @@ After any updates or changes to dependencies, you may need to do the following:
 4. [Regenerate lockfile](./docs/build/advanced_conan.md#conan-lockfile).
 5. Re-run [conan install](#build-and-test).

+If you are using the Nix development shell, whether prebuilt Conan binaries apply
+depends on your platform — see
+[Prebuilt packages](./docs/build/nix.md#prebuilt-packages).
+
 #### ERROR: Package not resolved

 If you're seeing an error like `ERROR: Package 'snappy/1.1.10' not resolved: Unable to find 'snappy/1.1.10#968fef506ff261592ec30c574d4a7809%1756234314.246' in remotes.`,
-please [add `xrplf` remote](#add-xrplf-remote) or re-run `conan export` for [patched recipes](./docs/build/advanced_conan.md#patched-recipes).
+please [set Conan up](#set-up-conan) so the `xrplf` remote is configured, or re-run `conan export` for [patched recipes](./docs/build/advanced_conan.md#patched-recipes).

 ### `protobuf/port_def.inc` file not found

@@ -412,7 +412,6 @@ For example, if you want to build Debug:
 1. For conan install, pass `--settings build_type=Debug`
 2. For cmake, pass `-DCMAKE_BUILD_TYPE=Debug`

-[cpp23-support]: https://en.cppreference.com/w/cpp/compiler_support/23
 [conan-getting-started]: https://docs.conan.io/en/latest/getting_started.html
 [unity-build]: https://en.wikipedia.org/wiki/Unity_build
 [gcovr]: https://gcovr.com/en/stable/getting-started.html
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -170,11 +170,19 @@ if(coverage)
    include(XrplCov)
 endif()

+add_custom_target(tidy_prerequisites)
+
+if(rust)
+    add_subdirectory(crates)
+endif()
 include(XrplCore)
+
 include(XrplProtocolAutogen)
 include(XrplInstall)
-include(XrplPackaging)
 include(XrplValidatorKeys)
+# Must come after XrplValidatorKeys: the 'package' target depends on the
+# validator-keys target existing.
+include(XrplPackaging)

 if(tests)
    include(CTest)
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -225,8 +225,9 @@ environment, so you don't need to install most of the individual tools
 yourself. The version of each hook sourced from an external repository
 (`clang-format`, `gersemi`, etc.) is pinned in that file, so running the hooks
 locally uses exactly the same versions as CI. A few `local` hooks — most notably
-`clang-tidy` — run tools from your own environment; see
-[Installing clang-tidy](#installing-clang-tidy) for how to get those.
+`clang-tidy` and `cargo fmt` — run tools from your own environment; see
+[Installing clang-tidy](#installing-clang-tidy) and
+[Rust](./docs/build/environment.md#rust) for how to get those.

 To get started, install `pre-commit` and enable the git hook scripts:

@@ -255,6 +256,7 @@ The hooks configured in this repository include, among others:
 - `clang-tidy` — C++ static analysis (see [Clang-tidy](#clang-tidy)); opt in with `TIDY=1`
 - `fix-include-style`, `fix-pragma-once`, `check-doxygen-style` — C++ hygiene
 - `gersemi` — CMake formatting
+- `cargo fmt` — Rust formatting for the crates in `crates/`
 - `prettier`, `black`, `shfmt` — formatting for JavaScript/JSON/Markdown, Python, and shell
 - `cspell` — spell checking

@@ -319,7 +321,11 @@ See the [environment setup guide](./docs/build/environment.md#clang-tidy) for ho

 ### Running clang-tidy locally

-Before running clang-tidy, you must build the project to generate required files (particularly protobuf headers). Refer to [`BUILD.md`](./BUILD.md) for build instructions.
+Before running clang-tidy, you must generate the files it depends on (protobuf headers, and, when the project is configured with `-Drust=ON`, the cxxbridge headers from the Rust crates). Configure the project as described in [`BUILD.md`](./BUILD.md), then build the `tidy_prerequisites` target, which generates all of them:
+
+```bash
+cmake --build build --target tidy_prerequisites
+```

 #### Via pre-commit (recommended)

--- a/README.md
+++ b/README.md
@@ -54,6 +54,7 @@ Here are some good places to start learning the source code:
 | `./docs`   | Source documentation files and doxygen config. |
 | `./cfg`    | Example configuration files.                   |
 | `./src`    | Source code.                                   |
+| `./crates` | Rust source code.                              |

 Some of the directories under `src` are external repositories included using
 git-subtree. See those directories' README files for more details.
--- a/bin/check-nix-store-refs.sh
+++ b/bin/check-nix-store-refs.sh
@@ -0,0 +1,111 @@
+#!/usr/bin/env bash
+# Fail if a binary under <path> records a /nix/store path it resolves at run
+# time. See docs/build/nix.md#prebuilt-packages for why that matters.
+#
+# <path> is a file or a directory. macOS: nothing may reference the store, so
+# point it at whole trees. Linux: the toolchain always writes the store into
+# PT_INTERP and RUNPATH, so only at what cmake/PatchNixBinary.cmake retargets.
+#
+# Only Mach-O / ELF is inspected. Static archives hold store paths in debug info
+# alone; the scripts in a Conan cache are all git hook samples and autotools
+# scratch, 36 false positives to 0 real.
+#
+# Usage: bin/check-nix-store-refs.sh <path>
+
+set -euo pipefail
+
+if [ "$#" -ne 1 ]; then
+    echo "usage: $0 <path>" >&2
+    exit 2
+fi
+
+if [ ! -e "$1" ]; then
+    echo "$0: no such path: $1" >&2
+    exit 2
+fi
+
+case "$(uname -s)" in
+    Darwin)
+        format=Mach-O
+        recorded_paths=macho_recorded_paths
+        tool=otool
+        ;;
+    Linux)
+        format=ELF
+        recorded_paths=elf_recorded_paths
+        tool=readelf
+        ;;
+    *)
+        echo "Unsupported OS - skipping the Nix store reference check."
+        exit 0
+        ;;
+esac
+
+# `pipefail` would catch this too, but only as a bare nonzero exit.
+if ! command -v "${tool}" >/dev/null; then
+    echo "$0: ${tool} not found; cannot inspect binaries" >&2
+    exit 2
+fi
+
+# Both list what the file records. `ldd` would answer what this machine resolves
+# now, which is wrong both ways: store paths for a correctly patched binary,
+# silence for a store RUNPATH that resolves nowhere.
+
+# `name` covers LC_ID_DYLIB and LC_LOAD*_DYLIB, `path` covers LC_RPATH.
+macho_recorded_paths() {
+    otool -l "$1" | sed -nE 's#^ *(name|path) ([^ ]*).*#\2#p'
+}
+
+# RPATH and RUNPATH are colon-separated.
+elf_recorded_paths() {
+    readelf -ldW "$1" |
+        sed -nE \
+            -e 's#.*program interpreter: ([^]]*)\].*#\1#p' \
+            -e 's#.*\((RPATH|RUNPATH|NEEDED)\).*\[([^]]*)\].*#\2#p' |
+        tr ':' '\n'
+}
+
+checked=0
+skipped=0
+leaked=0
+
+while IFS= read -r file; do
+    case "$(file -b "${file}" 2>/dev/null)" in
+        *"${format}"*) ;;
+        *)
+            skipped=$((skipped + 1))
+            continue
+            ;;
+    esac
+    checked=$((checked + 1))
+
+    # Filter after extracting, or a search path starting elsewhere ($ORIGIN)
+    # hides the rest. `sed` not `grep`: grep calls "no matches" a failure, and
+    # the `|| true` that would need masks a broken pipeline too.
+    refs="$("${recorded_paths}" "${file}" | sed -n '\#^/nix/store/#p' | sort -u)"
+    if [ -n "${refs}" ]; then
+        leaked=$((leaked + 1))
+        echo "::error file=${file}::references the Nix store at run time"
+        echo "${file}"
+        echo "${refs}" | sed 's/^/    /'
+    fi
+done < <(find "$1" -type f \( -perm -u+x -o -name '*.dylib' -o -name '*.so*' \))
+
+echo "$1: checked ${checked}, skipped ${skipped}, ${leaked} with Nix store references."
+
+if [ "${leaked}" -ne 0 ]; then
+    cat >&2 <<'EOF'
+
+Fixes, in order of preference:
+  - A Conan package built before this check existed: drop it
+    (`conan remove '<name>/*'`) and rebuild.
+  - A binary that should have been retargeted to the system loader: check that
+    cmake/PatchNixBinary.cmake ran for it.
+  - Link the macOS system library instead of the Nix one - see
+    libresolvSystemStub in nix/darwin.nix.
+  - No system library exists (libstdc++): link it statically.
+  - None of the above: pin the toolchain into the package ID, following
+    `user.package:libc_version` in conan/profiles/ci.
+EOF
+    exit 1
+fi
--- a/bin/check-tools.sh
+++ b/bin/check-tools.sh
@@ -15,10 +15,14 @@
 #   - Windows: the core build tools only (CMake, Conan, Git, Python).
 #              MSVC is expected to be provided separately and is not checked here.
 #
-# Some tools (clang-format, doxygen, gcovr, gh, git-cliff, gpg, pre-commit,
-# run-clang-tidy) are present in our Linux CI images and in local development
-# setups, but not in the macOS CI environment. They are checked everywhere
-# except when running in CI on macOS.
+# Some tools (clang-format, clang-tidy, doxygen, gcovr, gh, git-cliff, gpg,
+# pre-commit, run-clang-tidy) are present in our Linux CI images and in local
+# development setups, but not in the macOS CI environment. They are checked
+# everywhere except when running in CI on macOS.
+#
+# Tools that Nix also exposes under a version-suffixed name (`clang-tidy-22`,
+# `g++-15`, ...) are probed under both names: a suffixed name can break while
+# the plain one still works (see mkVersionedToolLinks in nix/packages.nix).
 #
 # Environment variables:
 #   CI                      if set, skip the tools above when on macOS.
@@ -26,14 +30,27 @@

 set -uo pipefail

+# Version suffixes of the Nix tool links, tracking nix/packages.nix.
+gcc_version=15
+llvm_version=22
+
 missing=()
 checked=0

+# tool_path <name>
+# Fully resolved path of a tool, so the snapshots record which derivation
+# provides it. Prints nothing when it isn't on PATH.
+tool_path() {
+    local path
+    path="$(command -v "$1" 2>/dev/null)" || return 0
+    readlink -f "${path}" 2>/dev/null || printf '%s' "${path}"
+}
+
 # check <name> [probe-command...]
 # Runs the probe (default: "<name> --version"), capturing both stdout and
-# stderr, and prints one aligned line: the status, the name, and the first
-# non-blank line of the probe output (its version). Records <name> as missing
-# if the command is not found or exits non-zero.
+# stderr, and prints three lines: the status and name, the first non-blank line
+# of the probe output (its version, or the error when it failed), and the tool's
+# resolved path. Records <name> as missing if it is not found or exits non-zero.
 check() {
    local name="$1"
    shift
@@ -43,14 +60,17 @@ check() {
    fi

    checked=$((checked + 1))
-    local output version
+    local output version path
+    path="$(tool_path "${name}")"
    if output="$("${probe[@]}" 2>&1)"; then
-        version="$(printf '%s\n' "${output}" | grep -m1 '[^[:space:]]' || true)"
-        printf '  [ ok ] %-20s %s\n' "${name}" "${version}"
+        printf '  ✅ %s\n' "${name}"
    else
-        printf '  [MISS] %s\n' "${name}"
+        printf '  ❌ %s\n' "${name}"
        missing+=("${name}")
    fi
+    version="$(printf '%s\n' "${output}" | grep -m1 '[^[:space:]]' || true)"
+    printf '     %s\n' "${version:-(no output)}"
+    printf '     %s\n' "${path:-(not found)}"
 }

 case "$(uname -s)" in
@@ -82,7 +102,9 @@ if [ "${os}" = "linux" ] || [ "${os}" = "macos" ]; then
    echo "Development tooling:"
    check ccache
    check clang
+    check "clang-${llvm_version}"
    check clang++
+    check "clang++-${llvm_version}"
    check ClangBuildAnalyzer
    check curl
    check file
@@ -101,7 +123,14 @@ if [ "${os}" = "linux" ] || [ "${os}" = "macos" ]; then
    # setups, but not in the macOS CI environment. So check them everywhere
    # except when running in CI on macOS.
    if [ "${os}" = "linux" ] || [ -z "${CI:-}" ]; then
+        check clang-apply-replacements
+        check "clang-apply-replacements-${llvm_version}"
        check clang-format
+        check "clang-format-${llvm_version}"
+        # clang-tidy leads --version with the LLVM banner, not the version.
+        tidy_probe="--version | grep -m1 -oE 'LLVM version [0-9.]+'"
+        check clang-tidy sh -c "clang-tidy ${tidy_probe}"
+        check "clang-tidy-${llvm_version}" sh -c "clang-tidy-${llvm_version} ${tidy_probe}"
        check dot
        check doxygen
        check gcovr
@@ -112,6 +141,7 @@ if [ "${os}" = "linux" ] || [ "${os}" = "macos" ]; then
        # pre-commit, or its alternative implementation prek
        check pre-commit sh -c 'pre-commit --version || prek --version'
        check run-clang-tidy run-clang-tidy --help
+        check "run-clang-tidy-${llvm_version}" "run-clang-tidy-${llvm_version}" --help
    fi
 fi

@@ -126,7 +156,7 @@ if [ "${os}" = "linux" ] || [ "${os}" = "macos" ]; then
    check cargo-audit cargo audit --version
    check cargo-llvm-cov cargo llvm-cov --version
    check cargo-nextest cargo nextest --version
-    check clippy clippy-driver --version
+    check clippy-driver
    check rust-analyzer
    check rustc
    check rustfmt
@@ -138,7 +168,11 @@ if [ "${os}" = "linux" ]; then
    echo
    echo "GCC toolchain:"
    check gcc
+    check "gcc-${gcc_version}"
    check g++
+    check "g++-${gcc_version}"
+    check cpp
+    check "cpp-${gcc_version}"
    check gcov

    echo
@@ -163,9 +197,9 @@ else
    checked=$((checked + 1))
    tmp_clone="$(mktemp -d)"
    if git clone --depth 1 https://github.com/XRPLF/actions.git "${tmp_clone}/actions" >/dev/null 2>&1; then
-        printf '  [ ok ] git clone over HTTPS\n'
+        printf '  ✅ git clone over HTTPS\n'
    else
-        printf '  [MISS] git clone over HTTPS\n'
+        printf '  ❌ git clone over HTTPS\n'
        missing+=("git-https-clone")
    fi
    rm -rf "${tmp_clone}"
@@ -173,9 +207,9 @@ fi

 echo
 if [ "${#missing[@]}" -eq 0 ]; then
-    echo "All ${checked} checked tools are present and runnable."
+    echo "✅ All ${checked} checked tools are present and runnable."
 else
-    echo "Missing or non-functional tools (${#missing[@]} of ${checked}):" >&2
+    echo "❌ Missing or non-functional tools (${#missing[@]} of ${checked}):" >&2
    for tool in "${missing[@]}"; do
        echo "  - ${tool}" >&2
    done
--- a/cfg/xrpld-example.cfg
+++ b/cfg/xrpld-example.cfg
@@ -488,6 +488,17 @@
 #   Must be a number between 100 and 1000, defaults to 250
 #
 #
+# [max_subscriptions_per_connection]
+#
+#   Maximum number of account, real-time account, and account-history
+#   subscriptions a single client connection may hold at once. Bounds the
+#   per-connection state torn down when the connection disconnects. Book
+#   subscriptions are tracked separately and are not counted here.
+#
+#   Defaults to 100000 if not set; large enough for legitimate power users
+#   such as block explorers.
+#
+#
 # [overlay]
 #
 #   Controls settings related to the peer to peer overlay.
@@ -538,6 +549,45 @@
 #       only be used for local testing and debugging. Do not disable
 #       on mainnet.
 #
+#   max_untrusted_count = <number>
+#
+#       The number of manifests the server keeps for validators it does not
+#       list, and the number it sends and processes in a single peer protocol
+#       message. Once the server holds this many, a manifest for a new
+#       unlisted validator is rejected, so peer gossip cannot grow the cache
+#       without end.
+#
+#       This option can take any value between 50 and 1000, inclusive. If
+#       the option is not present the server uses its built-in value.
+#
+#       The current default (which is subject to change) is 300.
+#
+#   max_trusted_count = <number>
+#
+#       The number of manifests for listed validators to allow for when
+#       sizing peer protocol messages. Manifests for listed validators are
+#       never dropped, whether sending or receiving, because doing so would
+#       delay a validator key change reaching this server. Set this above the
+#       number of validators the server lists.
+#
+#       Together the two counts above set the largest manifest message the
+#       server accepts: bigger messages are discarded without reading them,
+#       and without penalising the sender. Raising either means the server
+#       accepts and sends bigger messages than a peer using the defaults, and
+#       those peers will discard what this server sends. Lowering either below
+#       what peers send makes this server discard their manifest messages,
+#       which it does without recording anything.
+#
+#       This option can take any value between 50 and 1000, inclusive. If
+#       the option is not present the server uses its built-in value.
+#
+#       The current default (which is subject to change) is 300.
+#
+#       NOTE: These two options (max_untrusted_count and max_trusted_count)
+#       are transitional. They exist to bound manifest-message size and cache
+#       growth during the network upgrade. They may be removed in a future
+#       release once the fleet has upgraded, and should not be relied upon as
+#       stable configuration.
 #
 # [transaction_queue] EXPERIMENTAL
 #
--- a/cmake/PatchNixBinary.cmake
+++ b/cmake/PatchNixBinary.cmake
@@ -2,9 +2,10 @@
   Patch executables to run in non-Nix environments.

   The Nix toolchain links binaries against an ELF interpreter (loader)
-   that lives in the Nix store, so the resulting binaries don't run elsewhere.
-   `patch_nix_binary` adds a POST_BUILD step that resets the interpreter
-   to the system default loader and drops the rpath.
+   that lives in the Nix store, so the resulting binaries don't run elsewhere
+   (including once installed from the .deb package). `patch_nix_binary` resets
+   the interpreter to the system default loader and drops the rpath, once the
+   binary has been linked.

   This runs by default for Nix-toolchain builds (determined by whether the compiler resolves under /nix/store/).
   Those builds are where binaries get a Nix-store loader.
@@ -52,13 +53,38 @@ function(patch_nix_binary target)
    if(NOT PATCH_NIX_BINARIES)
        return()
    endif()
-    add_custom_command(
-        TARGET ${target}
-        POST_BUILD
-        COMMAND
-            "${PATCHELF_COMMAND}" --set-interpreter "${DEFAULT_LOADER_PATH}"
-            --remove-rpath "$<TARGET_FILE:${target}>"
-        COMMENT "Patching ${target}: set default loader, remove rpath"
-        VERBATIM
+
+    set(patch_command
+        "${PATCHELF_COMMAND}"
+        --set-interpreter
+        "${DEFAULT_LOADER_PATH}"
+        --remove-rpath
+        "$<TARGET_FILE:${target}>"
    )
+    set(comment "Patching ${target}: set default loader, remove rpath")
+
+    # POST_BUILD is the cheap way to do this: it runs only when the binary is
+    # relinked. It is also only available in the directory that defined the
+    # target, so for a target from elsewhere (e.g. a FetchContent subproject)
+    # fall back to a custom target that runs after the binary is linked. That
+    # one runs on every build, which is harmless because patchelf is idempotent.
+    get_target_property(target_source_dir ${target} SOURCE_DIR)
+    if("${target_source_dir}" STREQUAL "${CMAKE_CURRENT_SOURCE_DIR}")
+        add_custom_command(
+            TARGET ${target}
+            POST_BUILD
+            COMMAND ${patch_command}
+            COMMENT "${comment}"
+            VERBATIM
+        )
+    else()
+        add_custom_target(
+            ${target}-patch-nix
+            ALL
+            COMMAND ${patch_command}
+            COMMENT "${comment}"
+            VERBATIM
+        )
+        add_dependencies(${target}-patch-nix ${target})
+    endif()
 endfunction()
--- a/cmake/XrplCompiler.cmake
+++ b/cmake/XrplCompiler.cmake
@@ -266,10 +266,50 @@ elseif(use_lld)
    )
    if("${LD_VERSION}" MATCHES "LLD")
        target_link_libraries(common INTERFACE -fuse-ld=lld)
+        # remembered for the linker flag probe below
+        set(fuse_ld_flag "-fuse-ld=lld")
    endif()
    unset(LD_VERSION)
 endif()

+# Linker warnings are errors where we control the toolchain and the dependencies: CI and the Nix dev shell.
+# On non-Nix macOS we suppress the deployment target warning: an old Conan profile may not pin os.version.
+# Only the new Apple linker understands the flag, so probe the actual linker (lld may be selected above).
+if(is_macos OR is_linux)
+    if(is_ci OR is_nix_compiler)
+        if(is_macos)
+            set(fatal_warnings_flag "-Wl,-fatal_warnings")
+        else()
+            set(fatal_warnings_flag "-Wl,--fatal-warnings")
+        endif()
+        message(
+            STATUS
+            "Treating all linker warnings as errors (${fatal_warnings_flag})"
+        )
+        target_link_options(common INTERFACE "${fatal_warnings_flag}")
+        unset(fatal_warnings_flag)
+    elseif(is_macos)
+        set(silence_flag "-Wl,-deployment_target_mismatches,suppress")
+        set(probe_flags ${fuse_ld_flag} "${silence_flag}")
+        include(CheckLinkerFlag)
+        check_linker_flag(
+            CXX
+            "${probe_flags}"
+            have_deployment_target_mismatches
+        )
+        if(have_deployment_target_mismatches)
+            message(
+                STATUS
+                "Silencing macOS deployment target mismatch warnings (${silence_flag})"
+            )
+            target_link_options(common INTERFACE "${silence_flag}")
+        endif()
+        unset(probe_flags)
+        unset(silence_flag)
+    endif()
+endif()
+unset(fuse_ld_flag)
+
 if(assert)
    foreach(var_ CMAKE_C_FLAGS_RELEASE CMAKE_CXX_FLAGS_RELEASE)
        string(REGEX REPLACE "[-/]DNDEBUG" "" ${var_} "${${var_}}")
--- a/cmake/XrplCore.cmake
+++ b/cmake/XrplCore.cmake
@@ -51,6 +51,8 @@ target_compile_options(

 target_link_libraries(xrpl.libpb PUBLIC protobuf::libprotobuf gRPC::grpc++)

+add_dependencies(tidy_prerequisites xrpl.libpb)
+
 # TODO: Clean up the number of library targets later.
 add_library(xrpl.imports.main INTERFACE)

--- a/cmake/XrplCov.cmake
+++ b/cmake/XrplCov.cmake
@@ -44,6 +44,7 @@ setup_target_for_coverage_gcovr(
    EXCLUDE
        "src/test"
        "src/tests"
+        "src/benchmarks"
        "include/xrpl/beast/test"
        "include/xrpl/beast/unit_test"
        "${CMAKE_BINARY_DIR}/pb-xrpl.libpb"
--- a/cmake/XrplPackaging.cmake
+++ b/cmake/XrplPackaging.cmake
@@ -25,6 +25,19 @@ if(NOT (RPMBUILD_EXECUTABLE OR DPKG_BUILDPACKAGE_EXECUTABLE))
    return()
 endif()

+if(NOT TARGET xrpld)
+    message(STATUS "xrpld=ON is required; 'package' target not available")
+    return()
+endif()
+
+if(NOT TARGET validator-keys)
+    message(
+        STATUS
+        "validator_keys=ON is required; 'package' target not available"
+    )
+    return()
+endif()
+
 set(package_env
    SRC_DIR=${CMAKE_SOURCE_DIR}
    BUILD_DIR=${CMAKE_BINARY_DIR}
@@ -37,7 +50,7 @@ add_custom_target(
        ${CMAKE_COMMAND} -E env ${package_env}
        ${CMAKE_SOURCE_DIR}/package/build_pkg.sh
    WORKING_DIRECTORY ${CMAKE_BINARY_DIR}
-    DEPENDS xrpld
+    DEPENDS xrpld validator-keys
    COMMENT "Building Linux package (deb/rpm inferred from host tooling)"
    VERBATIM
 )
--- a/cmake/XrplSettings.cmake
+++ b/cmake/XrplSettings.cmake
@@ -32,6 +32,11 @@ endif()

 option(benchmark "Build benchmarks" ON)

+# When OFF, the crates directory is not added to the build at all: no Rust
+# toolchain is required, no cxxbridge bindings are generated, and the C++ tests
+# that consume those bindings are left out of the build tree.
+option(rust "Build the Rust crates and the C++ code that depends on them" OFF)
+
 # Enabled by default so every header is compiled on its own as the main file of
 # its own compile_commands.json entry - this is what lets clang-tidy (and clangd
 # and IDEs) analyse a header's own includes directly. The per-header objects are
--- a/cmake/XrplValidatorKeys.cmake
+++ b/cmake/XrplValidatorKeys.cmake
@@ -5,22 +5,39 @@ option(
 )

 if(validator_keys)
-    git_branch(current_branch)
-    # default to tracking VK master branch unless we are on release
-    if(NOT (current_branch STREQUAL "release"))
-        set(current_branch "master")
-    endif()
-    message(STATUS "Tracking ValidatorKeys branch: ${current_branch}")
+    # Own the install destination below rather than relying on another module
+    # having pulled this in first.
+    include(GNUInstallDirs)
+
+    # Pinned to an exact commit, not a branch: the tool ships inside our
+    # packages, so the same xrpld version must always package the same
+    # validator-keys. Bump this deliberately.
+    set(validator_keys_commit "4c0fb75eec9601c711645998c904507e87e910ae")
+    message(STATUS "Using ValidatorKeys commit: ${validator_keys_commit}")

    FetchContent_Declare(
        validator_keys
        GIT_REPOSITORY https://github.com/ripple/validator-keys-tool.git
-        GIT_TAG "${current_branch}"
+        GIT_TAG "${validator_keys_commit}"
    )
    FetchContent_MakeAvailable(validator_keys)
+    # The tool's own CMakeLists excludes the target from 'all' when it is built
+    # as a subproject. Undo that, so validator_keys=ON really does build it.
    set_target_properties(
        validator-keys
-        PROPERTIES RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}"
+        PROPERTIES
+            RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}"
+            EXCLUDE_FROM_ALL OFF
+            EXCLUDE_FROM_DEFAULT_BUILD OFF
+    )
+    # We ship this binary, so like xrpld it must not keep the Nix store's ELF
+    # loader, or it cannot run on the target distro at all.
+    patch_nix_binary(validator-keys)
+
+    configure_file(
+        "${validator_keys_SOURCE_DIR}/LICENSE"
+        "${CMAKE_BINARY_DIR}/validator-keys-LICENSE"
+        COPYONLY
    )
    install(TARGETS validator-keys RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
 endif()
--- a/conan.lock
+++ b/conan.lock
@@ -14,7 +14,7 @@
        "openssl/3.6.3#f806de8933e3bf6f01016c6a888cee2e%1783945160.863288",
        "nudb/2.0.9#11149c73f8f2baff9a0198fe25971fc7%1782392402.297166",
        "nlohmann_json/3.11.3#45828be26eb619a2e04ca517bb7b828d%1701220705.259",
-        "mpt-crypto/0.4.0-rc4#ffdba12f2332357f0d8b0ae944cfff52%1784138702.932355",
+        "mpt-crypto/1.0.2#b313cef0c1a493eb970ad185b2e9bab7%1784285108.866483",
        "lz4/1.10.0#982d9b673900f665a1da109e09c17cab%1782392402.164188",
        "libiconv/1.17#9923bc6dc6f106646d6967e0039a5ada%1782392792.775744",
        "libcurl/8.21.0#8c26e59c04891ba3373ea3552e18f67f%1783067699.863",
@@ -26,6 +26,7 @@
        "fast_float/8.2.10#f6f28d6bb22112078e7dbda611caf681%1785888854.601666",
        "ed25519/2015.03#ae761bdc52730a843f0809bdf6c1b1f6%1782307148.15562",
        "date/3.0.4#862e11e80030356b53c2c38599ceb32b%1782392402.538492",
+        "corrosion/0.6.1#bfa292df0a957bc70a450ff316cd9435%1786119416.131296",
        "c-ares/1.34.6#545240bb1c40e2cacd4362d6b8967650%1782392402.681654",
        "bzip2/1.0.8#c470882369c2d95c5c77e970c0c7e321%1782392402.296732",
        "boost/1.91.0#ea540ca2133d831b560036aa24dece3c%1782392419.475605",
--- a/conan/init.sh
+++ b/conan/init.sh
@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+# Install our Conan configuration, profiles and the xrplf remote into CONAN_HOME.
+# Safe to re-run; never deletes the Conan home.
+
+set -euo pipefail
+
+SCRIPT_DIR="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"
+CONAN_DIR="$(conan config home)"
+
+echo "Installing Conan configuration into ${CONAN_DIR}"
+conan config install "${SCRIPT_DIR}/global.conf"
+conan config install "${SCRIPT_DIR}/profiles" -tf "${CONAN_DIR}/profiles"
+# This script manages these files, so make them read-only - Conan does not
+# preserve the source mode. Only the files: the directories must stay writable
+# for `conan config install` to replace them.
+chmod a-w "${CONAN_DIR}/global.conf"
+find "${CONAN_DIR}/profiles" -type f -exec chmod a-w {} +
+
+echo "Adding the xrplf Conan remote"
+# --index 0: our patched recipes must win over Conan Center.
+conan remote add --index 0 --force xrplf https://conan.xrplf.org/repository/conan/
--- a/conan/profiles/default
+++ b/conan/profiles/default
@@ -1,10 +1,7 @@
 {% set os = detect_api.detect_os() %}
 {% set arch = detect_api.detect_arch() %}
 {% set compiler, version, compiler_exe = detect_api.detect_default_compiler() %}
-{% set compiler_version = version %}
-{% if os == "Linux" %}
 {% set compiler_version = detect_api.default_compiler_version(compiler, version) %}
-{% endif %}
 {% if os == "Macos" %}
 {# Minimum macOS the dependencies target. #}
 {# Without this, Conan builds each dependency against the (possibly newer) host SDK, so the #}
--- a/conanfile.py
+++ b/conanfile.py
@@ -29,6 +29,7 @@ class Xrpl(ConanFile):
    }

    requires = [
+        "corrosion/0.6.1",
        "ed25519/2015.03",
        "fast_float/8.2.10",
        "grpc/1.81.1",
@@ -141,7 +142,7 @@ class Xrpl(ConanFile):
        if self.options.jemalloc:
            self.requires("jemalloc/5.3.1")
        self.requires("lz4/1.10.0", force=True)
-        self.requires("mpt-crypto/0.4.0-rc4", transitive_headers=True)
+        self.requires("mpt-crypto/1.0.2", transitive_headers=True)
        self.requires("protobuf/6.33.5", force=True)
        if self.options.rocksdb:
            self.requires("rocksdb/10.5.1")
--- a/crates/.cargo/config.toml
+++ b/crates/.cargo/config.toml
@@ -0,0 +1,17 @@
+# The Rust static libraries are linked into C++ targets, so the runtime linkage
+# here has to match what the C++ build uses (see cmake/XrplCompiler.cmake).
+#
+# macOS needs nothing: AppleClang cannot link libgcc/libc++ statically, so the
+# C++ build skips those flags on Apple as well.
+
+# Both amd64 and arm64 Linux builds link libgcc statically. This only affects
+# links that rustc itself drives (`cargo test` binaries and the like) — the
+# `staticlib` crates consumed by CMake are archived, not linked, so rustc
+# silently ignores link args for them. Keeping libgcc_s.so.1 off the xrpld link
+# line is handled in crates/CMakeLists.txt instead.
+[target.'cfg(target_os = "linux")']
+rustflags = ["-C", "link-args=-static-libgcc"]
+
+# Windows builds use the static MSVC runtime.
+[target.'cfg(windows)']
+rustflags = ["-C", "target-feature=+crt-static"]
--- a/crates/CMakeLists.txt
+++ b/crates/CMakeLists.txt
@@ -0,0 +1,104 @@
+find_package(Corrosion REQUIRED)
+
+corrosion_import_crate(MANIFEST_PATH ${CMAKE_CURRENT_SOURCE_DIR}/Cargo.toml)
+
+# The generated C++ lands in the build tree, so put a .clang-tidy next to it to
+# keep clang-tidy from analyzing code we don't own.
+configure_file(
+    generated.clang-tidy
+    "${CMAKE_CURRENT_BINARY_DIR}/.clang-tidy"
+    COPYONLY
+)
+
+add_custom_target(xrpl_crates)
+add_dependencies(tidy_prerequisites xrpl_crates)
+
+# On macOS, ld warns `ignoring duplicate libraries` when linking a crate.
+# Corrosion is the source of both duplicates it names:
+#
+# * The crate archive and its cxxbridge archive, because
+#   `corrosion_add_cxxbridge` makes the two depend on each other, and CMake
+#   repeats a static library cycle on the link line so single-pass linkers can
+#   resolve it. (LINK_INTERFACE_MULTIPLICITY can only raise that count.)
+# * `-lSystem`, which Corrosion copies from rustc's `native-static-libs` even
+#   though the compiler driver always links libSystem.
+#
+# ld needs neither: it resolves the cycle from one copy of each archive and
+# links libSystem once. So silence the warning rather than rewrite Corrosion's
+# link interface, which the cycle is also part of. The option itself is old —
+# Xcode 15 is only where the warning became the default — and the check below
+# leaves it out on a linker that does not know it.
+if(is_macos)
+    include(CheckLinkerFlag)
+    check_linker_flag(
+        CXX
+        -Wl,-no_warn_duplicate_libraries
+        have_no_warn_duplicate_libraries
+    )
+endif()
+
+function(_unlink_libgcc_s crate)
+    if(NOT (is_linux AND static))
+        return()
+    endif()
+
+    # Corrosion exposes a crate's staticlib as an imported `<crate>-static`
+    # target and puts the native libs in its INTERFACE_LINK_LIBRARIES. If either
+    # of those changes, warn instead of silently letting libgcc_s.so.1 return.
+    set(imported "${crate}-static")
+    if(NOT TARGET ${imported})
+        message(
+            FATAL_ERROR
+            "Corrosion did not create the imported target '${imported}', so "
+            "libgcc_s cannot be removed from the link interface of '${crate}'. "
+            "xrpld will link libgcc_s.so.1 dynamically. Check where Corrosion "
+            "${CORROSION_VERSION} now records `native-static-libs`."
+        )
+        return()
+    endif()
+
+    get_target_property(libs ${imported} INTERFACE_LINK_LIBRARIES)
+    if(NOT "gcc_s" IN_LIST libs)
+        message(
+            WARNING
+            "'gcc_s' was not in the link interface of '${imported}' as "
+            "expected. If the Rust toolchain stopped reporting it this "
+            "workaround is obsolete and can be deleted; otherwise xrpld may "
+            "link libgcc_s.so.1 dynamically. Verify with: "
+            "objdump -p xrpld | grep NEEDED"
+        )
+        return()
+    endif()
+
+    list(REMOVE_ITEM libs gcc_s)
+    set_property(TARGET ${imported} PROPERTY INTERFACE_LINK_LIBRARIES ${libs})
+endfunction()
+
+function(add_xrpl_crate name)
+    cmake_parse_arguments(ARG "" "CRATE" "FILES" ${ARGN})
+    _unlink_libgcc_s(${ARG_CRATE})
+    # `cc` picks its runtime flag from `crt-static` alone, so it compiles a
+    # crate's C++ with `-MT`; Debug needs `-MTd` (to match cmake/XrplCompiler.cmake).
+    if(is_msvc)
+        corrosion_set_env_vars(
+            ${ARG_CRATE}
+            "$<$<CONFIG:Debug>:CXXFLAGS=-MTd>"
+        )
+    endif()
+    corrosion_add_cxxbridge(${name}_cxxbridge CRATE ${ARG_CRATE} FILES
+                            ${ARG_FILES}
+    )
+    # Generated cxxbridge headers don't exist at configure time; CMake 3.28+
+    # validates INTERFACE_SOURCES on consuming targets. Clear it to skip the
+    # existence check — build-time ordering is enforced by the custom commands.
+    set_target_properties(${name}_cxxbridge PROPERTIES INTERFACE_SOURCES "")
+    if(have_no_warn_duplicate_libraries)
+        target_link_options(
+            ${name}_cxxbridge
+            INTERFACE -Wl,-no_warn_duplicate_libraries
+        )
+    endif()
+    add_dependencies(xrpl_crates ${name}_cxxbridge)
+endfunction()
+
+add_xrpl_crate(rs_hello_world CRATE rs_hello_world FILES lib.rs)
--- a/crates/Cargo.lock
+++ b/crates/Cargo.lock
@@ -0,0 +1,301 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "anstyle"
+version = "1.0.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "940b3a0ca603d1eade50a4846a2afffd5ef57a9feac2c0e2ec2e14f9ead76000"
+
+[[package]]
+name = "cc"
+version = "1.2.61"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d16d90359e986641506914ba71350897565610e87ce0ad9e6f28569db3dd5c6d"
+dependencies = [
+ "find-msvc-tools",
+ "shlex",
+]
+
+[[package]]
+name = "clap"
+version = "4.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1ddb117e43bbf7dacf0a4190fef4d345b9bad68dfc649cb349e7d17d28428e51"
+dependencies = [
+ "clap_builder",
+]
+
+[[package]]
+name = "clap_builder"
+version = "4.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "714a53001bf66416adb0e2ef5ac857140e7dc3a0c48fb28b2f10762fc4b5069f"
+dependencies = [
+ "anstyle",
+ "clap_lex",
+ "strsim",
+]
+
+[[package]]
+name = "clap_lex"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c8d4a3bb8b1e0c1050499d1815f5ab16d04f0959b233085fb31653fbfc9d98f9"
+
+[[package]]
+name = "codespan-reporting"
+version = "0.13.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "af491d569909a7e4dee0ad7db7f5341fef5c614d5b8ec8cf765732aba3cff681"
+dependencies = [
+ "serde",
+ "termcolor",
+ "unicode-width",
+]
+
+[[package]]
+name = "cxx"
+version = "1.0.198"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6fe442a792c7c736eea18b32a7f8a3b63cf8aafabda6760042dc2fdeda456291"
+dependencies = [
+ "cc",
+ "cxx-build",
+ "cxxbridge-cmd",
+ "cxxbridge-flags",
+ "cxxbridge-macro",
+ "foldhash",
+ "link-cplusplus",
+]
+
+[[package]]
+name = "cxx-build"
+version = "1.0.198"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e3184a94384c663718698311a78a51ac00c484c10b4eeac06fb0a068c5f64fa2"
+dependencies = [
+ "cc",
+ "codespan-reporting",
+ "indexmap",
+ "proc-macro2",
+ "quote",
+ "scratch",
+ "syn 3.0.3",
+]
+
+[[package]]
+name = "cxxbridge-cmd"
+version = "1.0.198"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0148d8fd1199329ddf1d157a5e134e51ceff37c6a7ddd38615c399d81cb05d8d"
+dependencies = [
+ "clap",
+ "codespan-reporting",
+ "indexmap",
+ "proc-macro2",
+ "quote",
+ "syn 3.0.3",
+]
+
+[[package]]
+name = "cxxbridge-flags"
+version = "1.0.198"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "52850339faed2eaadd24e286dc1d8268cc6f8a7bd9524d713adc9099566b4c89"
+
+[[package]]
+name = "cxxbridge-macro"
+version = "1.0.198"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2c77c856545d886c9bd5215409ebb63b925e262135248b50c79e5a5f194ee47c"
+dependencies = [
+ "indexmap",
+ "proc-macro2",
+ "quote",
+ "syn 3.0.3",
+]
+
+[[package]]
+name = "equivalent"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "877a4ace8713b0bcf2a4e7eec82529c029f1d0619886d18145fea96c3ffe5c0f"
+
+[[package]]
+name = "find-msvc-tools"
+version = "0.1.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5baebc0774151f905a1a2cc41989300b1e6fbb29aff0ceffa1064fdd3088d582"
+
+[[package]]
+name = "foldhash"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "77ce24cb58228fbb8aa041425bb1050850ac19177686ea6e0f41a70416f56fdb"
+
+[[package]]
+name = "hashbrown"
+version = "0.17.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4f467dd6dccf739c208452f8014c75c18bb8301b050ad1cfb27153803edb0f51"
+
+[[package]]
+name = "indexmap"
+version = "2.14.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d466e9454f08e4a911e14806c24e16fba1b4c121d1ea474396f396069cf949d9"
+dependencies = [
+ "equivalent",
+ "hashbrown",
+]
+
+[[package]]
+name = "link-cplusplus"
+version = "1.0.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7f78c730aaa7d0b9336a299029ea49f9ee53b0ed06e9202e8cb7db9bae7b8c82"
+dependencies = [
+ "cc",
+]
+
+[[package]]
+name = "proc-macro2"
+version = "1.0.106"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8fd00f0bb2e90d81d1044c2b32617f68fcb9fa3bb7640c23e9c748e53fb30934"
+dependencies = [
+ "unicode-ident",
+]
+
+[[package]]
+name = "quote"
+version = "1.0.45"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "41f2619966050689382d2b44f664f4bc593e129785a36d6ee376ddf37259b924"
+dependencies = [
+ "proc-macro2",
+]
+
+[[package]]
+name = "rs-hello_world"
+version = "0.1.0"
+dependencies = [
+ "cxx",
+]
+
+[[package]]
+name = "scratch"
+version = "1.0.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d68f2ec51b097e4c1a75b681a8bec621909b5e91f15bb7b840c4f2f7b01148b2"
+
+[[package]]
+name = "serde"
+version = "1.0.228"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9a8e94ea7f378bd32cbbd37198a4a91436180c5bb472411e48b5ec2e2124ae9e"
+dependencies = [
+ "serde_core",
+ "serde_derive",
+]
+
+[[package]]
+name = "serde_core"
+version = "1.0.228"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "41d385c7d4ca58e59fc732af25c3983b67ac852c1a25000afe1175de458b67ad"
+dependencies = [
+ "serde_derive",
+]
+
+[[package]]
+name = "serde_derive"
+version = "1.0.228"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d540f220d3187173da220f885ab66608367b6574e925011a9353e4badda91d79"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.117",
+]
+
+[[package]]
+name = "shlex"
+version = "1.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0fda2ff0d084019ba4d7c6f371c95d8fd75ce3524c3cb8fb653a3023f6323e64"
+
+[[package]]
+name = "strsim"
+version = "0.11.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7da8b5736845d9f2fcb837ea5d9e2628564b3b043a70948a3f0b778838c5fb4f"
+
+[[package]]
+name = "syn"
+version = "2.0.117"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e665b8803e7b1d2a727f4023456bbbbe74da67099c585258af0ad9c5013b9b99"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
+[[package]]
+name = "syn"
+version = "3.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "53e9bae58849f64dfa4f5d5ae372c8341f7305f82a3868709269343628b659a3"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
+[[package]]
+name = "termcolor"
+version = "1.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "06794f8f6c5c898b3275aebefa6b8a1cb24cd2c6c79397ab15774837a0bc5755"
+dependencies = [
+ "winapi-util",
+]
+
+[[package]]
+name = "unicode-ident"
+version = "1.0.24"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e6e4313cd5fcd3dad5cafa179702e2b244f760991f45397d14d4ebf38247da75"
+
+[[package]]
+name = "unicode-width"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b4ac048d71ede7ee76d585517add45da530660ef4390e49b098733c6e897f254"
+
+[[package]]
+name = "winapi-util"
+version = "0.1.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c2a7b1c03c876122aa43f3020e6c3c3ee5c05081c9a00739faf7503aeba10d22"
+dependencies = [
+ "windows-sys",
+]
+
+[[package]]
+name = "windows-link"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f0805222e57f7521d6a62e36fa9163bc891acd422f971defe97d64e70d0a4fe5"
+
+[[package]]
+name = "windows-sys"
+version = "0.61.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ae137229bcbd6cdf0f7b80a31df61766145077ddf49416a728b02cb3921ff3fc"
+dependencies = [
+ "windows-link",
+]
--- a/crates/Cargo.toml
+++ b/crates/Cargo.toml
@@ -0,0 +1,15 @@
+[workspace]
+members = ["hello_world"]
+resolver = "3"
+
+[workspace.dependencies]
+cxx = { version = "1.0.198", features = ["c++20"] }
+
+[workspace.package]
+edition = "2024"
+
+[profile.release]
+opt-level = 3
+overflow-checks = true
+lto = true
+debug = true
--- a/crates/generated.clang-tidy
+++ b/crates/generated.clang-tidy
@@ -0,0 +1,10 @@
+---
+# Neutralizes clang-tidy for the corrosion/cxxbridge-generated C++. Copied into
+# the crates build directory by crates/CMakeLists.txt, next to the generated
+# sources, so clang-tidy picks it up instead of the top-level configuration.
+#
+# One check is kept enabled to avoid clang-tidy's "no checks enabled" error.
+Checks: "-*,google-readability-todo"
+WarningsAsErrors: ""
+HeaderFilterRegex: ""
+InheritParentConfig: false
--- a/crates/hello_world/Cargo.toml
+++ b/crates/hello_world/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "rs-hello_world"
+version = "0.1.0"
+edition.workspace = true
+
+[lib]
+crate-type = ["staticlib"]
+
+[dependencies]
+cxx.workspace = true
--- a/crates/hello_world/src/lib.rs
+++ b/crates/hello_world/src/lib.rs
@@ -0,0 +1,10 @@
+#[cxx::bridge(namespace = "rs::hello_world")]
+mod ffi {
+    extern "Rust" {
+        fn hello_world() -> String;
+    }
+}
+
+pub fn hello_world() -> String {
+    "hello_world".to_string()
+}
--- a/docs/NodeStoreRefactoringCaseStudy.pdf
+++ b/docs/NodeStoreRefactoringCaseStudy.pdf
--- a/docs/build/environment.md
+++ b/docs/build/environment.md
@@ -6,22 +6,55 @@ This document explains how to set one up.

 ## Tested compiler versions

-`xrpld` is built in the **C++23** dialect by default.
-Make sure your toolchain is recent enough — the compiler versions currently tested in CI are:
+`xrpld` is built in the **C++23** dialect by default, so your toolchain has to
+support it — see [compiler support for C++23][cpp23-support].
+The versions currently tested in CI are:

-| Compiler    | Version |
-| ----------- | ------- |
-| GCC         | 15.2    |
-| Clang       | 22      |
-| Apple Clang | 17      |
-| MSVC        | 19.44   |
+| Compiler    | Version            |
+| ----------- | ------------------ |
+| GCC         | 15.2               |
+| Clang       | 22                 |
+| Apple Clang | 21                 |
+| MSVC        | Visual Studio 2026 |

 LLVM tools (`clang-tidy` and `clang-format`) are also pinned to version 22.

+### Older compilers
+
 Older compilers may fail to build the latest `develop` code: the codebase now
 relies on C++23 features and has been adjusted for `clang-tidy`.
 If the latest code doesn't build for you, update your build toolchain first.

+If updating isn't an option for you, we do accept pull requests that fix builds
+on older compilers, as long as the change is small and doesn't make the code
+harder to read. What we can't promise is that older compilers will keep working:
+only the versions in the table above are tested in CI, and we won't hold back
+the use of C++23 features or add invasive workarounds to keep an untested
+compiler building. Treat support for anything outside the table as best-effort.
+
+## Required tools
+
+Besides a compiler, building `xrpld` requires:
+
+| Tool                                        | Minimum version |
+| ------------------------------------------- | --------------- |
+| [Git](https://git-scm.com/downloads)        | any recent      |
+| [Python](https://www.python.org/downloads/) | 3.11            |
+| [Conan](https://conan.io/downloads.html)    | 2.17            |
+| [CMake](https://cmake.org/download/)        | 3.16            |
+
+On Linux and macOS, the [Nix development shell](./nix.md) provides all of them
+(see below). On Windows they have to be installed manually.
+
+Building with `-Drust=ON` additionally requires a Rust toolchain, see
+[Rust](#rust). A default build does not, so it is not in the table above.
+
+Once they are in place, verify that everything is installed and runnable with:
+
+```bash
+./bin/check-tools.sh
+```
+
 ## Linux and macOS

 The **recommended way** to get a development environment on Linux and macOS is
@@ -39,20 +72,15 @@ Clang. If you instead opt to use your system-wide Apple Clang (via
 below).

 See [Using the Nix development shell](./nix.md) for installation and usage
-details, including how to select a different compiler.
-
-> [!NOTE]
-> Using Nix is not mandatory. Any custom environment (Homebrew packages or
-> anything else) will continue to work, but then it is up to you to keep it in
-> sync with the environment used in CI. Nix unifies the development environment
-> for everyone and synchronizes updates, which is why we recommend it.
+details, including how to select a different compiler and why we recommend Nix
+over a hand-maintained environment.

 ### macOS: managing the Apple Clang version

 If you use your system-wide Apple Clang on macOS (via `nix develop .#apple-clang`),
 the compiler version is whatever your installed Xcode (or Command Line Tools)
 provides. The following command should return a version greater than or equal to
-the [minimum required](#tested-compiler-versions):
+the [tested one](#tested-compiler-versions):

 ```bash
 clang --version
@@ -89,23 +117,42 @@ building xrpld. You may want to install and pin a specific version of Xcode:
 Nix is not available on Windows, so the required tools have to be installed
 manually:

- [Visual Studio 2022](https://visualstudio.microsoft.com/) with the
+- [Visual Studio 2026](https://visualstudio.microsoft.com/) with the
  **"Desktop development with C++"** workload — this provides MSVC and the
-  "x64 Native Tools Command Prompt".
+  "x64 Native Tools Command Prompt". CI configures CMake with the
+  `Visual Studio 18 2026` generator.
 - [Git for Windows](https://git-scm.com/download/win)
- [Python 3.11](https://www.python.org/downloads/), or higher
- [Conan 2.17](https://conan.io/downloads.html), or higher
- [CMake 3.22](https://cmake.org/download/), or higher
+- Python, Conan, and CMake, at the versions listed in
+  [Required tools](#required-tools).
+- a [Rust toolchain](https://rustup.rs) — only needed to build with
+  `-Drust=ON`, see [Rust](#rust)

-> [!NOTE]
-> Windows is used for development only and is not recommended for production.
+## Rust
+
+The repository contains a Rust workspace in [`crates/`](../../crates), whose
+crates are exposed to C++ through [cxx](https://cxx.rs) bindings. It is **not**
+part of a default build: the CMake `rust` option is OFF by default, and with it
+off no Rust toolchain is needed. It is only required when configuring with
+`-Drust=ON` (which is what CI does), see [Options](../../BUILD.md#options).
+
+The toolchain (`cargo`, `rustc`) is pinned to the channel in
+[`rust-toolchain.toml`](../../rust-toolchain.toml) at the repository root. If
+you install Rust with [rustup](https://rustup.rs), that file is picked up
+automatically, and `cargo`/`rustc` in the repository will use the pinned
+version.
+
+Everything else the Rust build needs on the CMake side comes from Conan along
+with the rest of the dependencies, so there is nothing further to install.

 ## Clang-tidy

 `clang-tidy` is required to run static analysis checks locally (see
 [CONTRIBUTING.md](../../CONTRIBUTING.md)). It is not required to build the
-project. This project currently uses `clang-tidy` version 22.
+project. The version this project uses is listed in
+[Tested compiler versions](#tested-compiler-versions).

-On Linux and macOS, the [Nix development shell](./nix.md) provides `clang-tidy`
-22 out of the box — run it via `run-clang-tidy`. No separate installation is
-needed.
+On Linux and macOS, the [Nix development shell](./nix.md) provides that exact
+version out of the box — run it via `run-clang-tidy`. No separate installation
+is needed.
+
+[cpp23-support]: https://en.cppreference.com/w/cpp/compiler_support/23
--- a/docs/build/nix.md
+++ b/docs/build/nix.md
@@ -7,7 +7,7 @@ This guide explains how to use Nix to set up a reproducible development environm
 ## Benefits of Using Nix

 - **Reproducible environment**: Everyone gets the same versions of tools and compilers
- **Matches CI**: The Linux CI runs in Docker images built from this exact Nix environment
+- **Matches CI**: The Linux CI runs in Docker images built from this exact Nix environment, and CI builds some macOS configurations in it as well
 - **No system pollution**: Dependencies are isolated and don't affect your system packages
 - **Consistent compilers**: The GCC and Clang shells use the same versions as CI
 - **Quick setup**: Get started with a single command
@@ -68,7 +68,7 @@ A compiler can be chosen by providing its name with the `.#` prefix, e.g. `nix d

 On Linux, `.#gcc` and `.#clang` provide the exact toolchain CI uses:
 the compiler (pinned in [`nix/packages.nix`](../../nix/packages.nix))
-rebuilt against the pinned custom glibc (see [`nix/compilers.nix`](../../nix/compilers.nix)).
+rebuilt against the pinned custom glibc (see [`nix/linux.nix`](../../nix/linux.nix)).
 Building that toolchain the first time is slow unless it is fetched from a Nix binary cache.
 If you don't need the custom glibc, the Linux-only `.#gcc-plain` and `.#clang-plain`
 give you the stock nixpkgs compilers of the same versions.
@@ -120,7 +120,7 @@ nix develop -c "$SHELL"
 >
 > If it doesn't, either adjust your shell configuration so it doesn't override `$PATH`, or use [direnv](#automatic-activation-with-direnv) (below), which loads the environment _after_ your shell config and so takes precedence regardless of the shell you use.

-## Building xrpld with Nix
+## Building xrpld in the Nix shell

 Once inside the Nix development shell, follow the standard [build instructions](../../BUILD.md#steps). The Nix shell provides all necessary tools (CMake, Ninja, Conan, etc.).

@@ -128,6 +128,100 @@ Coverage builds (`-Dcoverage=ON`) work in the `gcc` shell (and `gcc-plain` on Li
 each ships a `gcov` matching its compiler, since Nix's cc-wrapper does not expose one.
 The `clang` shells do not include `llvm-cov`, so use a `gcc` shell for coverage.

+Builds of the Rust crates (`-Drust=ON`) also work out of the box: every shell
+provides the Rust toolchain pinned in
+[`rust-toolchain.toml`](../../rust-toolchain.toml) (see
+[Rust](./environment.md#rust)), plus the `cargo-audit`, `cargo-llvm-cov` and
+`cargo-nextest` plugins.
+
+## Conan configuration
+
+The shell runs [`conan/init.sh`](../../conan/init.sh) on entry, so
+[Set Up Conan](../../BUILD.md#set-up-conan) is already done for you. It installs
+into the shell's own Conan home: `CONAN_HOME=~/.conan2-nix`.
+
+### Prebuilt packages
+
+On **Linux**, the binaries on the `xrplf` remote are built in this same Nix
+environment — CI runs in Docker images that bundle the dev shell's toolchain (see
+[`nix/docker`](../../nix/docker)) — so `.#gcc` and `.#clang` can reuse them. The
+`-plain` shells do not match that toolchain's glibc, so binaries from the remote
+are not a reliable match there.
+
+On **macOS**, CI also builds in this Nix environment, in Debug and Release (the
+`macos-arm64-*-nix` configurations — Debug because the profile defaults to it).
+The Nix build resolves to `compiler=clang`, so it gets its own package IDs,
+separate from the Apple Clang ones. The
+[dependency upload](../../.github/workflows/upload-conan-deps.yml) publishes them
+on pushes to `develop` and on manual runs — its nightly run rebuilds everything
+from source but uploads nothing — so once a set has been published `nix develop`
+can reuse it instead of compiling every dependency locally. These configurations
+run outside the reduced pull-request matrix, so label a PR `Full CI build` when it
+touches `flake.lock` or `nix/`.
+
+To compile everything from source, add `--build '*'` to the `conan install`
+command.
+
+### Why the nixpkgs revision is not part of the package ID
+
+A Conan package ID records the compiler and its major version, but nothing about
+the nixpkgs revision the toolchain came from — and `flake.lock` moves far more
+often than the toolchain meaningfully changes, so folding it in would rebuild
+every dependency on every bump for nothing.
+
+That is safe as long as no cached artifact resolves a `/nix/store` path at run
+time, because store paths change on every update and the old ones disappear with
+`nix-collect-garbage`. With the `clang` toolchain macOS CI and the dev shell use,
+they do not: it links against `/usr/lib/libc++` and `/usr/lib/libSystem`, and
+store paths reach the `.a` files only through debug info, which nothing resolves
+at link or run time.
+
+> [!WARNING]
+> This does not hold for `nix develop .#gcc` on macOS. There is no system
+> libstdc++, so GCC links its own from the store and every binary keeps a
+> `/nix/store` reference. That shell is fine for tooling, but it is not a build
+> configuration CI covers, and no dependency binaries are published for it.
+
+This is checked rather than assumed.
+[`bin/check-nix-store-refs.sh`](../../bin/check-nix-store-refs.sh) takes one file
+or directory and fails if a binary under it resolves a store path at run time.
+CI runs it over the build output and the Conan cache, and again in the upload job
+before anything is published. You can run it yourself:
+
+```bash
+bin/check-nix-store-refs.sh build
+bin/check-nix-store-refs.sh ~/.conan2-nix
+```
+
+It works on Linux too, but asserts something narrower there: the toolchain always
+writes the store into `PT_INTERP` and `RUNPATH`, and CI builds inside an image
+whose store is fixed for its lifetime, so that is fine. Only the binaries
+[`PatchNixBinary.cmake`](../../cmake/PatchNixBinary.cmake) retargets to the
+system loader have to be clean, and those are what CI checks:
+
+```bash
+bin/check-nix-store-refs.sh build/xrpld
+```
+
+### The libresolv stub
+
+This is not hypothetical: `xrpld` used to be caught by it. The c-ares package
+tells the linker to pass `-lresolv`, and nixpkgs keeps `libresolv` out of the
+macOS SDK and ships it as an ordinary store dylib — so every Nix-built `xrpld`
+recorded a `/nix/store/…-libresolv-93/lib/libresolv.9.dylib` load command and
+stopped running once that path was collected. Nothing in the link uses a single
+symbol from it.
+
+Both environments now put a stub on the linker search path
+(`libresolvSystemStub` in [`nix/darwin.nix`](../../nix/darwin.nix)): the
+same library with its install name set to `/usr/lib/libresolv.9.dylib`, which is
+exactly the load command the Apple Clang build records.
+
+Package IDs did not change, so Conan keeps serving anything built before the
+stub landed. If a binary fails to start with `Library not loaded: /nix/store/…`,
+see [that entry](./nix_troubleshooting.md#library-not-loaded-nixstore-from-a-binary-that-used-to-work)
+in the troubleshooting guide.
+
 ## Automatic Activation with direnv

 [direnv](https://direnv.net/) or [nix-direnv](https://github.com/nix-community/nix-direnv) can automatically activate the Nix development shell when you enter the repository directory.
@@ -142,14 +236,6 @@ The repository already ships an `.envrc` at its root that activates the Nix flak
 > [!NOTE]
 > direnv only caches the `.direnv` directory (already listed in `.gitignore`); no other repository files are affected.

-## Conan and Prebuilt Packages
-
-Please note that there is no guarantee that binaries from conan cache will work when using nix. If you encounter any errors, please use `--build '*'` to force conan to compile everything from source:
-
-```bash
-conan install .. --output-folder . --build '*' --settings build_type=Release
-```
-
 ## Updating `flake.lock` file

 To update `flake.lock` to the latest revision use `nix flake update` command.
--- a/docs/build/nix_troubleshooting.md
+++ b/docs/build/nix_troubleshooting.md
@@ -131,3 +131,91 @@ once it picks up that rebuild, then re-run the `grep libgit2` check above to
 confirm it reports `1.9.4` or newer.

 Until then, prefer the workarounds above.
+
+## `wint_t` / `uint32_t` errors from the Nix libc++ headers
+
+A build that mixes the Nix toolchain with the system SDK fails in libc++ itself,
+with errors that look nothing like your code:
+
+```
+/nix/store/...-libcxx-.../include/c++/v1/cwchar:136:9: error: target of using declaration conflicts with declaration already in scope
+  136 | using ::wint_t _LIBCPP_USING_IF_EXISTS;
+/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/sys/_types/_wint_t.h:32:25: note: target of using declaration
+...
+error: use of undeclared identifier 'UINT32_C'
+```
+
+The give-away is the second path: Nix's libc++ headers are being combined with
+the **Xcode Command Line Tools** SDK instead of the Nix one.
+
+### Why it happens
+
+`SDKROOT` and `DEVELOPER_DIR` are what point the toolchain at the Nix SDK, and
+they are not baked into the compiler — a dev shell gets them from the
+`apple-sdk` setup hook. CMake, finding neither, asks `xcrun`, which answers with
+the system SDK. Nix's `libc++` and Apple's headers then declare the same types
+twice.
+
+### Fix
+
+Run the build from inside the dev shell (`nix develop`), or from an environment
+that exports both variables. To confirm which SDK a configured build is using:
+
+```bash
+grep -o '\-isysroot [^ ]*' build/compile_commands.json | sort -u
+```
+
+It should print a `/nix/store/...-apple-sdk-*` path. If it prints
+`/Library/Developer/CommandLineTools/...`, re-configure from within the shell —
+CMake caches the sysroot, so an existing `build/` directory keeps the wrong one.
+
+## `Library not loaded: /nix/store/…` from a binary that used to work
+
+A binary stops starting after a `nix flake update`, or after
+`nix-collect-garbage` removes the paths the previous toolchain used:
+
+```
+dyld[57271]: Library not loaded: /nix/store/…-libresolv-93/lib/libresolv.9.dylib
+```
+
+[`bin/check-nix-store-refs.sh`](../../bin/check-nix-store-refs.sh) finds the same
+thing without having to run anything, and names the file:
+
+```
+$ bin/check-nix-store-refs.sh ~/.conan2-nix
+::error file=/Users/you/.conan2-nix/p/b/c-area24ded30c388c/p/bin/adig::references the Nix store at run time
+/Users/you/.conan2-nix/p/b/c-area24ded30c388c/p/bin/adig
+    /nix/store/p4lp3xq4imd1qzqh08x8vcq2zfhi7rca-libresolv-93/lib/libresolv.9.dylib
+/Users/you/.conan2-nix: checked 135, skipped 2495, 1 with Nix store references.
+```
+
+Conan's cache folders are named after a truncated package name plus a hash, so
+ask Conan which package the offending one belongs to — pass the folder holding
+the hash, not the file itself:
+
+```
+$ conan cache ref ~/.conan2-nix/p/b/c-area24ded30c388c
+c-ares/1.34.6#545240bb1c40e2cacd4362d6b8967650:dab5992496abe6d219defb7986ecbf367615a5e5#…
+```
+
+### Why it happens
+
+The binary records a store path that no longer exists. Nothing we build should:
+see [Prebuilt packages](./nix.md#prebuilt-packages) for why, and
+`libresolvSystemStub` in [`nix/darwin.nix`](../../nix/darwin.nix) for the one
+dependency that needed help to comply.
+
+A Conan package ID does not encode the nixpkgs revision, so a package built
+before that stub existed stays in your local cache and keeps being reused. The
+dev shell is also what tends to produce one: it is a slightly _less_ isolated
+build environment than CI's, because `mkShell` puts every tool's headers and
+libraries on the compiler's search path — which is how c-ares found the Nix
+`libresolv` in the first place.
+
+### Fix
+
+Drop that package and let Conan refetch or rebuild it:
+
+```bash
+conan remove 'c-ares/*'
+```
--- a/docs/install-legacy.md
+++ b/docs/install-legacy.md
@@ -1,3 +1,10 @@
+# Installing xrpld 3.3.0 and earlier
+
+> [!IMPORTANT]
+> These instructions apply to xrpld 3.3.0 and earlier, published to
+> repos.ripple.com.
+> For later releases see [install.md](./install.md).
+
 This document contains instructions for installing xrpld.
 The APT package manager is common on Debian-based Linux distributions like
 Ubuntu,
@@ -52,7 +59,7 @@ The default [prefix][1] is typically `/usr/local` on Linux and macOS and

 5.  Add the appropriate XRPL repository for your operating system version:

-        echo "deb [signed-by=/usr/local/share/keyrings/ripple-key.gpg] https://repos.ripple.com/repos/xrpld-deb focal stable" | \
+        echo "deb [signed-by=/usr/local/share/keyrings/ripple-key.gpg] https://repos.ripple.com/repos/rippled-deb focal stable" | \
            sudo tee -a /etc/apt/sources.list.d/ripple.list

    The above example is appropriate for **Ubuntu 20.04 Focal Fossa**. For other operating systems, replace the word `focal` with one of the following:
@@ -106,8 +113,8 @@ The default [prefix][1] is typically `/usr/local` on Linux and macOS and
        enabled=1
        gpgcheck=0
        repo_gpgcheck=1
-        baseurl=https://repos.ripple.com/repos/xrpld-rpm/stable/
-        gpgkey=https://repos.ripple.com/repos/xrpld-rpm/stable/repodata/repomd.xml.key
+        baseurl=https://repos.ripple.com/repos/rippled-rpm/stable/
+        gpgkey=https://repos.ripple.com/repos/rippled-rpm/stable/repodata/repomd.xml.key
        REPOFILE

    _Unstable_
@@ -118,8 +125,8 @@ The default [prefix][1] is typically `/usr/local` on Linux and macOS and
        enabled=1
        gpgcheck=0
        repo_gpgcheck=1
-        baseurl=https://repos.ripple.com/repos/xrpld-rpm/unstable/
-        gpgkey=https://repos.ripple.com/repos/xrpld-rpm/unstable/repodata/repomd.xml.key
+        baseurl=https://repos.ripple.com/repos/rippled-rpm/unstable/
+        gpgkey=https://repos.ripple.com/repos/rippled-rpm/unstable/repodata/repomd.xml.key
        REPOFILE

    _Nightly_
@@ -130,8 +137,8 @@ The default [prefix][1] is typically `/usr/local` on Linux and macOS and
        enabled=1
        gpgcheck=0
        repo_gpgcheck=1
-        baseurl=https://repos.ripple.com/repos/xrpld-rpm/nightly/
-        gpgkey=https://repos.ripple.com/repos/xrpld-rpm/nightly/repodata/repomd.xml.key
+        baseurl=https://repos.ripple.com/repos/rippled-rpm/nightly/
+        gpgkey=https://repos.ripple.com/repos/rippled-rpm/nightly/repodata/repomd.xml.key
        REPOFILE

 2.  Fetch the latest repo updates:
--- a/docs/install.md
+++ b/docs/install.md
@@ -0,0 +1,144 @@
+# Installing xrpld
+
+> [!NOTE]
+> These instructions apply to packages published from 2026-08-19 onwards.
+> For xrpld 3.3.0 and earlier see [install-legacy.md](./install-legacy.md).
+
+`xrpld` is published as DEB and RPM packages for 64-bit x86 Linux.
+Use APT on Debian-based distributions such as Debian and Ubuntu,
+and YUM on Red Hat-based distributions such as RHEL, AlmaLinux, and Rocky Linux.
+To build from source instead, see [BUILD.md](../BUILD.md).
+
+## Release channels
+
+Packages are published to four channels:
+
+- `stable` - the latest production release
+- `unstable` - release candidates
+- `experimental` - beta builds
+- `develop` - every push to the [`develop` branch](https://github.com/XRPLF/rippled/tree/develop)
+
+See [Publishing packages](../package/README.md#publishing-packages) for how channels are produced.
+
+The instructions below use `stable`.
+To follow another channel, replace `stable` with its name
+wherever it appears in the repository configuration.
+
+> [!WARNING]
+> Channels other than `stable` may be broken at any time.
+> Do not use them for production servers.
+
+## Install the xrpld package
+
+### With the APT package manager
+
+1.  Install utilities:
+
+    ```bash
+    sudo apt update -y
+    sudo apt install -y apt-transport-https ca-certificates curl gnupg
+    ```
+
+2.  Add the XRPL Foundation package-signing key to your list of trusted keys:
+
+    ```bash
+    sudo install -d -m 0755 /etc/apt/keyrings
+    sudo curl -fsS https://packages.xrplf.org/xrplf.asc -o /etc/apt/keyrings/xrplf.asc
+    ```
+
+3.  Check the fingerprint of the newly-added key:
+
+    ```bash
+    gpg --show-keys /etc/apt/keyrings/xrplf.asc
+    ```
+
+    The output should be:
+
+    ```text
+    pub   rsa4096 2026-08-18 [SC]
+          B655416741221F780FBCFBC9AA84D41A11D29FA9
+    uid                      XRPLF Packages <distribution@xrplf.org>
+    ```
+
+    In particular, make sure that the fingerprint matches.
+
+4.  Add the repository, using the channel you picked in [Release channels](#release-channels):
+
+    ```bash
+    echo "deb [signed-by=/etc/apt/keyrings/xrplf.asc] https://packages.xrplf.org/repository/deb-stable focal main" | \
+        sudo tee /etc/apt/sources.list.d/xrplf.list
+    ```
+
+5.  Fetch the repository:
+
+    ```bash
+    sudo apt -y update
+    ```
+
+6.  Install the `xrpld` software package:
+
+    ```bash
+    sudo apt -y install xrpld
+    ```
+
+### With the YUM package manager
+
+1.  Add the XRPL Foundation package-signing key:
+
+    ```bash
+    sudo rpm --import https://packages.xrplf.org/xrplf.asc
+    ```
+
+2.  Add the repository, using the channel you picked in [Release channels](#release-channels):
+
+    ```bash
+    cat << REPOFILE | sudo tee /etc/yum.repos.d/xrplf.repo
+    [xrplf-stable]
+    name=XRP Ledger Packages
+    enabled=1
+    baseurl=https://packages.xrplf.org/repository/rpm-stable/
+    gpgcheck=1
+    repo_gpgcheck=0
+    gpgkey=https://packages.xrplf.org/xrplf.asc
+    REPOFILE
+    ```
+
+    `gpgcheck=1` verifies each package against the key above.
+    `repo_gpgcheck` is off because the repository metadata is generated by the server and is not signed.
+
+3.  Install the `xrpld` package:
+
+    ```bash
+    sudo yum install -y xrpld
+    ```
+
+## The xrpld service
+
+Both package managers install a systemd unit and enable it, so `xrpld` starts on boot.
+Check whether it is already running:
+
+```bash
+systemctl status xrpld.service
+```
+
+The APT packages start it immediately as well; the YUM packages do not, so start it yourself:
+
+```bash
+sudo systemctl start xrpld.service
+```
+
+### Optional: binding to privileged ports
+
+To serve incoming API requests on port 80 or 443, grant the service the capability to bind them.
+You must also update the config file's port settings.
+
+```bash
+sudo install -d -m 0755 /etc/systemd/system/xrpld.service.d
+sudo tee /etc/systemd/system/xrpld.service.d/privileged-ports.conf >/dev/null <<'EOF'
+[Service]
+CapabilityBoundingSet=CAP_NET_BIND_SERVICE
+AmbientCapabilities=CAP_NET_BIND_SERVICE
+EOF
+sudo systemctl daemon-reload
+sudo systemctl restart xrpld.service
+```
--- a/docs/sample_chart.doc
+++ b/docs/sample_chart.doc
@@ -1,24 +0,0 @@
-/*!
-    \page somestatechart Example state diagram
-
-    \startuml SomeState "my state diagram"
-    scale 600 width
-
-    [*] -> State1
-    State1 --> State2 : Succeeded
-    State1 --> [*] : Aborted
-    State2 --> State3 : Succeeded
-    State2 --> [*] : Aborted
-    state State3 {
-      state "Accumulate Enough Data\nLong State Name" as long1
-      long1 : Just a test
-      [*] --> long1
-      long1 --> long1 : New Data
-      long1 --> ProcessData : Enough Data
-    }
-    State3 --> State3 : Failed
-    State3 --> [*] : Succeeded / Save Result
-    State3 --> [*] : Aborted
-
-    \enduml
-*/
--- a/include/xrpl/basics/Archive.h
+++ b/include/xrpl/basics/Archive.h
@@ -1,6 +1,6 @@
 #pragma once

-#include <boost/filesystem.hpp>
+#include <filesystem>

 namespace xrpl {

@@ -13,6 +13,6 @@ namespace xrpl {
 * @throws runtime_error
 */
 void
-extractTarLz4(boost::filesystem::path const& src, boost::filesystem::path const& dst);
+extractTarLz4(std::filesystem::path const& src, std::filesystem::path const& dst);

 }  // namespace xrpl
--- a/include/xrpl/basics/Buffer.h
+++ b/include/xrpl/basics/Buffer.h
@@ -3,6 +3,7 @@
 #include <xrpl/basics/Slice.h>
 #include <xrpl/beast/utility/instrumentation.h>

+#include <algorithm>
 #include <cstdint>
 #include <cstring>
 #include <memory>
@@ -156,6 +157,19 @@ public:
    }
    /** @} */

+    /**
+     * Set every byte in the buffer to the given value.
+     *
+     * The size is unchanged, and this is a no-op on an empty buffer.
+     *
+     * @param value the byte to write to every position.
+     */
+    void
+    fill(std::uint8_t value) noexcept
+    {
+        std::fill_n(p_.get(), size_, value);
+    }
+
    /**
     * Reset the buffer.
     * All memory is deallocated. The resulting size is 0.
@@ -226,10 +240,4 @@ operator==(Buffer const& lhs, Buffer const& rhs) noexcept
    return std::memcmp(lhs.data(), rhs.data(), lhs.size()) == 0;
 }

-inline bool
-operator!=(Buffer const& lhs, Buffer const& rhs) noexcept
-{
-    return !(lhs == rhs);
-}
-
 }  // namespace xrpl
--- a/include/xrpl/basics/FileUtilities.h
+++ b/include/xrpl/basics/FileUtilities.h
@@ -1,24 +1,79 @@
 #pragma once

-#include <boost/filesystem.hpp>
-#include <boost/system/error_code.hpp>
-
 #include <cstddef>
+#include <filesystem>
 #include <optional>
 #include <string>
+#include <system_error>

 namespace xrpl {

 std::string
 getFileContents(
-    boost::system::error_code& ec,
-    boost::filesystem::path const& sourcePath,
+    std::error_code& ec,
+    std::filesystem::path const& sourcePath,
    std::optional<std::size_t> maxSize = std::nullopt);

 void
 writeFileContents(
-    boost::system::error_code& ec,
-    boost::filesystem::path const& destPath,
+    std::error_code& ec,
+    std::filesystem::path const& destPath,
    std::string const& contents);

+/**
+ * Generate a unique, non-existing path under @p base whose filename starts with
+ * @p prefix and ends with a random hex suffix.
+ *
+ * Attempts up to @p maxAttempts paths. Throws `std::runtime_error` if a unique
+ * path cannot be found or if the filesystem returns an error while checking for
+ * existence.
+ */
+std::filesystem::path
+uniqueRandomPath(
+    std::filesystem::path const& base,
+    std::string const& prefix = "",
+    std::size_t maxAttempts = 100);
+
+/**
+ * RAII temporary directory.
+ *
+ * The directory and all its contents are deleted when
+ * the instance of `TempDir` is destroyed.
+ */
+class TempDir
+{
+    std::filesystem::path path_;
+
+public:
+#if !GENERATING_DOCS
+    TempDir(TempDir const&) = delete;
+    TempDir&
+    operator=(TempDir const&) = delete;
+#endif
+
+    /**
+     * Construct a temporary directory.
+     */
+    TempDir();
+
+    /**
+     * Destroy a temporary directory.
+     */
+    ~TempDir();
+
+    /**
+     * Get the native path for the temporary directory.
+     */
+    [[nodiscard]] std::string
+    path() const;
+
+    /**
+     * Get the native path for a file.
+     *
+     * The file does not need to exist.
+     */
+    [[nodiscard]] std::string
+    file(std::string const& name) const;
+};
+
 }  // namespace xrpl
--- a/include/xrpl/basics/IntrusivePointer.h
+++ b/include/xrpl/basics/IntrusivePointer.h
@@ -96,9 +96,6 @@ public:
    SharedIntrusive&
    operator=(SharedIntrusive const& rhs);

-    bool
-    operator!=(std::nullptr_t) const;
-
    bool
    operator==(std::nullptr_t) const;

--- a/include/xrpl/basics/IntrusivePointer.ipp
+++ b/include/xrpl/basics/IntrusivePointer.ipp
@@ -111,13 +111,6 @@ SharedIntrusive<T>::operator=(SharedIntrusive<TT>&& rhs)
    return *this;
 }

-template <class T>
-bool
-SharedIntrusive<T>::operator!=(std::nullptr_t) const
-{
-    return this->get() != nullptr;
-}
-
 template <class T>
 bool
 SharedIntrusive<T>::operator==(std::nullptr_t) const
--- a/include/xrpl/basics/Log.h
+++ b/include/xrpl/basics/Log.h
@@ -3,8 +3,8 @@
 #include <xrpl/beast/utility/Journal.h>

 #include <boost/beast/core/string.hpp>
-#include <boost/filesystem.hpp>

+#include <filesystem>
 #include <fstream>
 #include <map>
 #include <memory>
@@ -84,7 +84,7 @@ private:
         * @return `true` if the file was opened.
         */
        bool
-        open(boost::filesystem::path const& path);
+        open(std::filesystem::path const& path);

        /**
         * Close and re-open the system file associated with the log
@@ -133,7 +133,7 @@ private:

    private:
        std::unique_ptr<std::ofstream> stream_;
-        boost::filesystem::path path_;
+        std::filesystem::path path_;
    };

    std::mutex mutable mutex_;
@@ -152,7 +152,7 @@ public:
    virtual ~Logs() = default;

    bool
-    open(boost::filesystem::path const& pathToLogFile);
+    open(std::filesystem::path const& pathToLogFile);

    beast::Journal::Sink&
    get(std::string const& name);
--- a/include/xrpl/basics/Number.h
+++ b/include/xrpl/basics/Number.h
@@ -304,7 +304,7 @@ concept Integral64 = std::is_same_v<T, std::int64_t> || std::is_same_v<T, std::u
 *      on-ledger are non-negative. This is due to implementation details of
 *      several operations which use unsigned arithmetic internally. This is
 *      sufficient to represent all valid XRP values (where the absolute value
- *      can not exceed INITIAL_XRP: 10^17), and MPT values (where the absolute
+ *      can not exceed kInitialXRP: 10^17), and MPT values (where the absolute
 *      value can not exceed maxMPTokenAmount: 2^63-1).
 *
 * ---- Mantissa Range Switching ----
@@ -449,12 +449,6 @@ public:
            x.exponent_ == y.exponent_;
    }

-    friend constexpr bool
-    operator!=(Number const& x, Number const& y) noexcept
-    {
-        return !(x == y);
-    }
-
    friend constexpr bool
    operator<(Number const& l, Number const& r) noexcept
    {
--- a/include/xrpl/basics/SHAMapHash.h
+++ b/include/xrpl/basics/SHAMapHash.h
@@ -85,12 +85,6 @@ public:
    }
 };

-inline bool
-operator!=(SHAMapHash const& x, SHAMapHash const& y)
-{
-    return !(x == y);
-}
-
 template <>
 inline std::size_t
 extract(SHAMapHash const& key)
--- a/include/xrpl/basics/Slice.h
+++ b/include/xrpl/basics/Slice.h
@@ -208,12 +208,6 @@ operator==(Slice const& lhs, Slice const& rhs) noexcept
    return std::memcmp(lhs.data(), rhs.data(), lhs.size()) == 0;
 }

-inline bool
-operator!=(Slice const& lhs, Slice const& rhs) noexcept
-{
-    return !(lhs == rhs);
-}
-
 inline bool
 operator<(Slice const& lhs, Slice const& rhs) noexcept
 {
--- a/include/xrpl/basics/StringUtilities.h
+++ b/include/xrpl/basics/StringUtilities.h
@@ -2,7 +2,6 @@

 #include <xrpl/basics/Blob.h>

-#include <boost/format.hpp>
 #include <boost/utility/string_view.hpp>

 #include <array>
@@ -125,9 +124,31 @@ struct ParsedUrl
 bool
 parseUrl(ParsedUrl& pUrl, std::string const& strUrl);

+/**
+ * Remove leading and trailing ASCII whitespace.
+ *
+ * Whitespace is the fixed set " \t\n\v\f\r"; the current locale is not
+ * consulted, so the result depends only on the input.
+ *
+ * @param str The string to trim.
+ * @return @p str without leading or trailing whitespace.
+ */
 std::string
 trimWhitespace(std::string str);

+/**
+ * Fold ASCII upper case letters to lower case.
+ *
+ * Only 'A' through 'Z' are remapped; every other byte is left alone and the
+ * current locale is not consulted, so the result depends only on the input.
+ *
+ * @param str The string to fold.
+ * @return @p str with each ASCII upper case letter replaced by its lower case
+ *         equivalent.
+ */
+std::string
+toLower(std::string str);
+
 std::optional<std::uint64_t>
 toUInt64(std::string const& s);

--- a/include/xrpl/basics/base64.h
+++ b/include/xrpl/basics/base64.h
@@ -41,6 +41,35 @@

 namespace xrpl {

+namespace base64 {
+
+/**
+ * Returns the maximum number of characters needed to base64-encode @p nBytes bytes.
+ *
+ * @param nBytes Number of input bytes.
+ * @return Size of the encoded string, including padding.
+ */
+constexpr std::size_t
+encodedSize(std::size_t const nBytes)
+{
+    return 4 * ((nBytes + 2) / 3);
+}
+
+/**
+ * Returns the maximum number of bytes a base64 string of @p numChars characters
+ * decodes to.
+ *
+ * @param numChars Number of base64 characters.
+ * @return Upper bound on the number of decoded bytes.
+ */
+constexpr std::size_t
+decodedSize(std::size_t const numChars)
+{
+    return ((numChars / 4) * 3) + 2;
+}
+
+}  // namespace base64
+
 std::string
 base64Encode(std::uint8_t const* data, std::size_t len);

--- a/include/xrpl/basics/partitioned_unordered_map.h
+++ b/include/xrpl/basics/partitioned_unordered_map.h
@@ -116,12 +116,6 @@ public:
        {
            return lhs.map == rhs.map && lhs.ait == rhs.ait && lhs.mit == rhs.mit;
        }
-
-        friend bool
-        operator!=(Iterator const& lhs, Iterator const& rhs)
-        {
-            return !(lhs == rhs);
-        }
    };

    struct ConstIterator
@@ -189,12 +183,6 @@ public:
        {
            return lhs.map == rhs.map && lhs.ait == rhs.ait && lhs.mit == rhs.mit;
        }
-
-        friend bool
-        operator!=(ConstIterator const& lhs, ConstIterator const& rhs)
-        {
-            return !(lhs == rhs);
-        }
    };

 private:
--- a/include/xrpl/beast/container/detail/aged_ordered_container.h
+++ b/include/xrpl/beast/container/detail/aged_ordered_container.h
@@ -1038,25 +1038,6 @@ public:
               Compare,
               OtherAllocator> const& other) const;

-    template <
-        bool OtherIsMulti,
-        bool OtherIsMap,
-        class OtherT,
-        class OtherDuration,
-        class OtherAllocator>
-    bool
-    operator!=(AgedOrderedContainer<
-               OtherIsMulti,
-               OtherIsMap,
-               Key,
-               OtherT,
-               OtherDuration,
-               Compare,
-               OtherAllocator> const& other) const
-    {
-        return !(this->operator==(other));
-    }
-
    template <
        bool OtherIsMulti,
        bool OtherIsMap,
--- a/include/xrpl/beast/container/detail/aged_unordered_container.h
+++ b/include/xrpl/beast/container/detail/aged_unordered_container.h
@@ -1340,28 +1340,6 @@ public:
               OtherAllocator> const& other) const
        requires MaybeMulti;

-    template <
-        bool OtherIsMulti,
-        bool OtherIsMap,
-        class OtherKey,
-        class OtherT,
-        class OtherDuration,
-        class OtherHash,
-        class OtherAllocator>
-    bool
-    operator!=(AgedUnorderedContainer<
-               OtherIsMulti,
-               OtherIsMap,
-               OtherKey,
-               OtherT,
-               OtherDuration,
-               OtherHash,
-               KeyEqual,
-               OtherAllocator> const& other) const
-    {
-        return !(this->operator==(other));
-    }
-
 private:
    bool
    wouldExceed(size_type additional) const
--- a/include/xrpl/beast/core/List.h
+++ b/include/xrpl/beast/core/List.h
@@ -82,13 +82,6 @@ public:
        return node_ == other.node_;
    }

-    template <typename M>
-    bool
-    operator!=(ListIterator<M> const& other) const noexcept
-    {
-        return !((*this) == other);
-    }
-
    reference
    operator*() const noexcept
    {
--- a/include/xrpl/beast/net/IPEndpoint.h
+++ b/include/xrpl/beast/net/IPEndpoint.h
@@ -110,12 +110,6 @@ public:
    operator==(Endpoint const& lhs, Endpoint const& rhs);
    friend bool
    operator<(Endpoint const& lhs, Endpoint const& rhs);
-
-    friend bool
-    operator!=(Endpoint const& lhs, Endpoint const& rhs)
-    {
-        return !(lhs == rhs);
-    }
    friend bool
    operator>(Endpoint const& lhs, Endpoint const& rhs)
    {
--- a/include/xrpl/beast/rfc2616.h
+++ b/include/xrpl/beast/rfc2616.h
@@ -11,6 +11,7 @@
 #include <cstddef>
 #include <iterator>
 #include <string>
+#include <string_view>
 #include <vector>

 namespace beast::rfc2616 {
@@ -186,7 +187,7 @@ splitCommas(FwdIt first, FwdIt last)

 template <class Result = std::vector<std::string>>
 Result
-splitCommas(boost::beast::string_view const& s)
+splitCommas(std::string_view s)
 {
    return splitCommas(s.begin(), s.end());
 }
@@ -229,12 +230,6 @@ public:
        return other.it_ == it_ && other.end_ == end_ && other.value_.size() == value_.size();
    }

-    bool
-    operator!=(ListIterator const& other) const
-    {
-        return !(*this == other);
-    }
-
    reference
    operator*() const
    {
--- a/include/xrpl/beast/unit_test/reporter.h
+++ b/include/xrpl/beast/unit_test/reporter.h
@@ -8,7 +8,6 @@
 #include <xrpl/beast/unit_test/runner.h>
 #include <xrpl/beast/unit_test/suite_info.h>

-#include <boost/lexical_cast.hpp>
 #include <boost/optional.hpp>

 #include <algorithm>
@@ -188,7 +187,7 @@ Reporter<Unused>::fmtdur(clock_type::duration const& d)
    using namespace std::chrono;
    auto const ms = duration_cast<milliseconds>(d);
    if (ms < seconds{1})
-        return boost::lexical_cast<std::string>(ms.count()) + "ms";
+        return std::to_string(ms.count()) + "ms";
    std::stringstream ss;
    ss << std::fixed << std::setprecision(1) << (ms.count() / 1000.) << "s";
    return ss.str();
--- a/include/xrpl/beast/unit_test/suite.h
+++ b/include/xrpl/beast/unit_test/suite.h
@@ -6,11 +6,10 @@

 #include <xrpl/beast/unit_test/runner.h>

-#include <boost/filesystem.hpp>
-#include <boost/lexical_cast.hpp>
 #include <boost/throw_exception.hpp>

 #include <exception>
+#include <filesystem>
 #include <memory>
 #include <ostream>
 #include <sstream>
@@ -27,10 +26,10 @@ makeReason(String const& reason, char const* file, int line)
    std::string s(reason);
    if (!s.empty())
        s.append(": ");
-    namespace fs = boost::filesystem;
+    namespace fs = std::filesystem;
    s.append(fs::path{file}.filename().string());
    s.append("(");
-    s.append(boost::lexical_cast<std::string>(line));
+    s.append(std::to_string(line));
    s.append(")");
    return s;
 }
--- a/include/xrpl/beast/utility/temp_dir.h
+++ b/include/xrpl/beast/utility/temp_dir.h
@@ -1,71 +0,0 @@
-#pragma once
-
-#include <boost/filesystem.hpp>
-
-#include <string>
-
-namespace beast {
-
-/**
- * RAII temporary directory.
- *
- * The directory and all its contents are deleted when
- * the instance of `temp_dir` is destroyed.
- */
-class TempDir
-{
-    boost::filesystem::path path_;
-
-public:
-#if !GENERATING_DOCS
-    TempDir(TempDir const&) = delete;
-    TempDir&
-    operator=(TempDir const&) = delete;
-#endif
-
-    /**
-     * Construct a temporary directory.
-     */
-    TempDir()
-    {
-        auto const dir = boost::filesystem::temp_directory_path();
-        do
-        {
-            path_ = dir / boost::filesystem::unique_path();
-        } while (boost::filesystem::exists(path_));
-        boost::filesystem::create_directory(path_);
-    }
-
-    /**
-     * Destroy a temporary directory.
-     */
-    ~TempDir()
-    {
-        // use non-throwing calls in the destructor
-        boost::system::error_code ec;
-        boost::filesystem::remove_all(path_, ec);
-        // TODO: warn/notify if ec set ?
-    }
-
-    /**
-     * Get the native path for the temporary directory
-     */
-    [[nodiscard]] std::string
-    path() const
-    {
-        return path_.string();
-    }
-
-    /**
-     * Get the native path for the a file.
-     *
-     * The file does not need to exist.
-     */
-    [[nodiscard]] std::string
-    file(std::string const& name) const
-    {
-        return (path_ / name).string();
-    }
-};
-
-}  // namespace beast
--- a/include/xrpl/conditions/Condition.h
+++ b/include/xrpl/conditions/Condition.h
@@ -92,10 +92,4 @@ operator==(Condition const& lhs, Condition const& rhs)
        lhs.fingerprint == rhs.fingerprint;
 }

-inline bool
-operator!=(Condition const& lhs, Condition const& rhs)
-{
-    return !(lhs == rhs);
-}
-
 }  // namespace xrpl::cryptoconditions
--- a/include/xrpl/conditions/Fulfillment.h
+++ b/include/xrpl/conditions/Fulfillment.h
@@ -93,12 +93,6 @@ operator==(Fulfillment const& lhs, Fulfillment const& rhs)
        lhs.fingerprint() == rhs.fingerprint();
 }

-inline bool
-operator!=(Fulfillment const& lhs, Fulfillment const& rhs)
-{
-    return !(lhs == rhs);
-}
-
 /**
 * Determine whether the given fulfillment and condition match
 */
--- a/include/xrpl/config/BasicConfig.h
+++ b/include/xrpl/config/BasicConfig.h
@@ -2,7 +2,6 @@

 #include <xrpl/basics/contract.h>

-#include <boost/beast/core/string.hpp>
 #include <boost/lexical_cast.hpp>

 #include <algorithm>
--- a/include/xrpl/config/Constants.h
+++ b/include/xrpl/config/Constants.h
@@ -25,6 +25,7 @@ struct Sections
    static constexpr auto kLedgerHistory = "ledger_history";
    static constexpr auto kLedgerReplay = "ledger_replay";
    static constexpr auto kLedgerTxTables = "ledger_tx_tables";
+    static constexpr auto kMaxSubscriptionsPerConnection = "max_subscriptions_per_connection";
    static constexpr auto kMaxTransactions = "max_transactions";
    static constexpr auto kNetworkId = "network_id";
    static constexpr auto kNetworkQuorum = "network_quorum";
@@ -118,7 +119,9 @@ struct Keys
    static constexpr auto kLogInterval = "log_interval";
    static constexpr auto kMaxDivergedTime = "max_diverged_time";
    static constexpr auto kMaxLedgerCountsToStore = "max_ledger_counts_to_store";
+    static constexpr auto kMaxTrustedCount = "max_trusted_count";
    static constexpr auto kMaxUnknownTime = "max_unknown_time";
+    static constexpr auto kMaxUntrustedCount = "max_untrusted_count";
    static constexpr auto kMaximumTxnInLedger = "maximum_txn_in_ledger";
    static constexpr auto kMaximumTxnPerAccount = "maximum_txn_per_account";
    static constexpr auto kMemoryLevel = "memory_level";
--- a/include/xrpl/consensus/Consensus.h
+++ b/include/xrpl/consensus/Consensus.h
@@ -23,6 +23,7 @@
 #include <map>
 #include <memory>
 #include <optional>
+#include <ranges>
 #include <sstream>
 #include <string>
 #include <string_view>
@@ -1748,7 +1749,13 @@ Consensus<Adaptor>::updateOurPositions(std::unique_ptr<std::stringstream> const&
        JLOG(j_.info()) << ss.str();
        CLOG(clog) << ss.str();

-        for (auto const& [t, v] : closeTimeVotes)
+        // Walk the votes highest-time first so that, among close times tied
+        // for the most votes, the earliest wins. The smaller value is the
+        // safer choice: without close-time consensus this round, the winner
+        // only updates our position for the next proposal, and a too-early
+        // time is bounded below by the prior ledger's close time. Only the
+        // tie-break changes; the bin with the most votes still wins.
+        for (auto const& [t, v] : std::views::reverse(closeTimeVotes))
        {
            JLOG(j_.debug()) << "CCTime: seq "
                             << static_cast<std::uint32_t>(previousLedger_.seq()) + 1 << ": "
--- a/include/xrpl/consensus/ConsensusTypes.h
+++ b/include/xrpl/consensus/ConsensusTypes.h
@@ -8,7 +8,9 @@

 #include <chrono>
 #include <cstddef>
+#include <cstdint>
 #include <map>
+#include <optional>
 #include <string>

 namespace xrpl {
@@ -211,6 +213,75 @@ struct ConsensusCloseTimes
    NetClock::time_point self;
 };

+/**
+ * Offset of the network's close time relative to ours, using a weighted median.
+ *
+ * Treats the sample set as `{self x 1}` merged with `{t x w}` for each
+ * `(t, w)` in `times.peers`, in time order, and returns `(median - self)`
+ * in whole seconds. Uses the lower weighted median: the median is the
+ * earliest time at which the running weight reaches half the total, so an
+ * even total whose halfway point falls between two bins resolves to the
+ * earlier bin.
+ *
+ * @param times Our own close time and the weighted close times of peers.
+ * @return Weighted median of all close times minus our own, in whole seconds.
+ */
+inline std::chrono::seconds
+medianCloseOffset(ConsensusCloseTimes const& times)
+{
+    using namespace std::chrono;
+    using time_point = NetClock::time_point;
+
+    std::int64_t totalWeight = 1;
+    for (auto const& [_, w] : times.peers)
+        totalWeight += w;
+
+    std::int64_t const halfWeight = (totalWeight + 1) / 2;
+
+    std::optional<time_point> median{};
+    std::int64_t tally = 0;
+    bool selfPlaced = false;
+
+    // Accumulate weight in time order; the first bin to reach halfWeight is
+    // the (lower) weighted median. Returns true once that bin is found.
+    auto step = [&](time_point t, std::int64_t w) {
+        XRPL_ASSERT(tally < halfWeight, "xrpl::medianCloseOffset::step : median not yet found");
+        tally += w;
+        if (tally >= halfWeight)
+        {
+            median = t;
+            return true;
+        }
+        return false;
+    };
+
+    for (auto const& [t, w] : times.peers)
+    {
+        if (!selfPlaced && times.self <= t)
+        {
+            selfPlaced = true;
+            if (step(times.self, 1))
+                break;
+        }
+        if (step(t, w))
+            break;
+    }
+    if (!selfPlaced && !median)
+        step(times.self, 1);
+
+    if (!median)
+    {
+        // LCOV_EXCL_START
+        UNREACHABLE("xrpl::medianCloseOffset : median not found");
+        median = times.self;
+        // LCOV_EXCL_STOP
+    }
+
+    return duration_cast<seconds>(
+        duration<std::int64_t>{median->time_since_epoch().count()} -
+        duration<std::int64_t>{times.self.time_since_epoch().count()});
+}
+
 /**
 * Whether we have or don't have a consensus
 */
--- a/include/xrpl/core/PerfLog.h
+++ b/include/xrpl/core/PerfLog.h
@@ -4,10 +4,9 @@
 #include <xrpl/core/Job.h>
 #include <xrpl/json/json_value.h>

-#include <boost/filesystem.hpp>
-
 #include <chrono>
 #include <cstdint>
+#include <filesystem>
 #include <functional>
 #include <memory>
 #include <string>
@@ -44,7 +43,7 @@ public:
     */
    struct Setup
    {
-        boost::filesystem::path perfLog;
+        std::filesystem::path perfLog;
        // log_interval is in milliseconds to support faster testing.
        milliseconds logInterval{seconds(1)};
    };
@@ -149,7 +148,7 @@ public:
 };

 PerfLog::Setup
-setupPerfLog(Section const& section, boost::filesystem::path const& configDir);
+setupPerfLog(Section const& section, std::filesystem::path const& configDir);

 std::unique_ptr<PerfLog>
 makePerfLog(
--- a/include/xrpl/json/Output.h
+++ b/include/xrpl/json/Output.h
@@ -1,20 +1,19 @@
 #pragma once

-#include <boost/beast/core/string.hpp>
-
 #include <functional>
 #include <string>
+#include <string_view>

 namespace json {

 class Value;

-using Output = std::function<void(boost::beast::string_view const&)>;
+using Output = std::function<void(std::string_view)>;

 inline Output
 stringOutput(std::string& s)
 {
-    return [&](boost::beast::string_view const& b) { s.append(b.data(), b.size()); };
+    return [&](std::string_view b) { s.append(b.data(), b.size()); };
 }

 /**
--- a/include/xrpl/json/json_value.h
+++ b/include/xrpl/json/json_value.h
@@ -4,6 +4,7 @@
 #include <xrpl/json/json_forwards.h>

 #include <cstring>
+#include <iterator>
 #include <limits>
 #include <map>
 #include <string>
@@ -72,36 +73,18 @@ operator==(StaticString x, StaticString y)
    return strcmp(x.cStr(), y.cStr()) == 0;
 }

-inline bool
-operator!=(StaticString x, StaticString y)
-{
-    return !(x == y);
-}
-
 inline bool
 operator==(std::string const& x, StaticString y)
 {
    return strcmp(x.c_str(), y.cStr()) == 0;
 }

-inline bool
-operator!=(std::string const& x, StaticString y)
-{
-    return !(x == y);
-}
-
 inline bool
 operator==(StaticString x, std::string const& y)
 {
    return y == x;
 }

-inline bool
-operator!=(StaticString x, std::string const& y)
-{
-    return !(y == x);
-}
-
 /**
 * @brief Represents a <a HREF="http://www.json.org">JSON</a> value.
 *
@@ -489,12 +472,6 @@ toJson(xrpl::Number const& number)
 bool
 operator==(Value const&, Value const&);

-inline bool
-operator!=(Value const& x, Value const& y)
-{
-    return !(x == y);
-}
-
 bool
 operator<(Value const&, Value const&);

@@ -548,6 +525,7 @@ public:
 class ValueIteratorBase
 {
 public:
+    using iterator_category = std::bidirectional_iterator_tag;
    using size_t = unsigned int;
    using difference_type = int;
    using SelfType = ValueIteratorBase;
@@ -562,12 +540,6 @@ public:
        return isEqual(other);
    }

-    bool
-    operator!=(SelfType const& other) const
-    {
-        return !isEqual(other);
-    }
-
    /**
     * Return either the index or the member name of the referenced value as a
     * Value.
--- a/include/xrpl/ledger/BookDirs.h
+++ b/include/xrpl/ledger/BookDirs.h
@@ -49,12 +49,6 @@ public:
    bool
    operator==(const_iterator const& other) const;

-    bool
-    operator!=(const_iterator const& other) const
-    {
-        return !(*this == other);
-    }
-
    reference
    operator*() const;

--- a/include/xrpl/ledger/CanonicalTXSet.h
+++ b/include/xrpl/ledger/CanonicalTXSet.h
@@ -59,12 +59,6 @@ private:
            return lhs.txId_ == rhs.txId_;
        }

-        friend bool
-        operator!=(Key const& lhs, Key const& rhs)
-        {
-            return !(lhs == rhs);
-        }
-
        [[nodiscard]] uint256 const&
        getAccount() const
        {
--- a/include/xrpl/ledger/Dir.h
+++ b/include/xrpl/ledger/Dir.h
@@ -59,12 +59,6 @@ public:
    bool
    operator==(ConstIterator const& other) const;

-    bool
-    operator!=(ConstIterator const& other) const
-    {
-        return !(*this == other);
-    }
-
    reference
    operator*() const;

--- a/include/xrpl/ledger/View.h
+++ b/include/xrpl/ledger/View.h
@@ -35,6 +35,11 @@ enum class SkipEntry : bool { No = false, Yes };
 //
 //------------------------------------------------------------------------------

+/**
+ * Whether an expiration check should be inclusive or exclusive.
+ */
+enum class ExpiryComparison { Inclusive, Exclusive };
+
 /**
 * Determines whether the given expiration time has passed.
 *
@@ -54,11 +59,16 @@ enum class SkipEntry : bool { No = false, Yes };
 *
 * @param view The ledger whose parent time is used as the clock.
 * @param exp The optional expiration time we want to check.
+ * @param comparison Whether the boundary is inclusive (`now >= exp`, the
+ *                   default) or exclusive (`now > exp`).
 *
 * @return `true` if `exp` is in the past; `false` otherwise.
 */
 [[nodiscard]] bool
-hasExpired(ReadView const& view, std::optional<std::uint32_t> const& exp);
+hasExpired(
+    ReadView const& view,
+    std::optional<std::uint32_t> const& exp,
+    ExpiryComparison comparison = ExpiryComparison::Inclusive);

 // Note, depth parameter is used to limit the recursion depth
 [[nodiscard]] bool
@@ -68,6 +78,13 @@ isVaultPseudoAccountFrozen(
    MPTIssue const& mptShare,
    std::uint8_t depth);

+[[nodiscard]] bool
+isVaultPseudoAccountFrozen(
+    ReadView const& view,
+    AccountID const& account,
+    SLE const& issuanceSle,
+    std::uint8_t depth);
+
 [[nodiscard]] bool
 isLPTokenFrozen(
    ReadView const& view,
@@ -75,6 +92,26 @@ isLPTokenFrozen(
    Asset const& asset,
    Asset const& asset2);

+/**
+ * Check whether an AMM LPToken may be transferred between @p from and @p to.
+ *
+ * @p lpTokenIssuer is the issuer of the LPToken being moved. If it is not an
+ * AMM account the token is not an LPToken and the transfer is unconditionally
+ * permitted. Otherwise, for each MPT pool asset of that AMM, canTransfer() must
+ * permit the transfer (which exempts the MPT issuer). Non-MPT pool assets are
+ * always transferable by this check, so it is implicitly gated by
+ * featureMPTokensV2 (MPTs can only be AMM pool assets once V2 is enabled).
+ *
+ * @return tesSUCCESS if permitted, otherwise the canTransfer() failure code
+ * (e.g. tecNO_AUTH) of the first MPT pool asset that disallows it.
+ */
+[[nodiscard]] TER
+canTransferLPToken(
+    ReadView const& view,
+    AccountID const& from,
+    AccountID const& to,
+    AccountID const& lpTokenIssuer);
+
 // Return the list of enabled amendments
 [[nodiscard]] std::set<uint256>
 getEnabledAmendments(ReadView const& view);
--- a/include/xrpl/ledger/detail/ReadViewFwdRange.h
+++ b/include/xrpl/ledger/detail/ReadViewFwdRange.h
@@ -85,9 +85,6 @@ public:
        bool
        operator==(Iterator const& other) const;

-        bool
-        operator!=(Iterator const& other) const;
-
        // Can throw
        reference
        operator*() const;
--- a/include/xrpl/ledger/detail/ReadViewFwdRange.ipp
+++ b/include/xrpl/ledger/detail/ReadViewFwdRange.ipp
@@ -64,13 +64,6 @@ ReadViewFwdRange<ValueType>::Iterator::operator==(Iterator const& other) const
    return impl_ == other.impl_;
 }

-template <class ValueType>
-bool
-ReadViewFwdRange<ValueType>::Iterator::operator!=(Iterator const& other) const
-{
-    return !(*this == other);
-}
-
 template <class ValueType>
 auto
 ReadViewFwdRange<ValueType>::Iterator::operator*() const -> reference
--- a/include/xrpl/ledger/helpers/AMMHelpers.h
+++ b/include/xrpl/ledger/helpers/AMMHelpers.h
@@ -226,7 +226,7 @@ getAMMOfferStartWithTakerGets(

    auto getAmounts = [&pool, &tfee](Number const& nTakerGetsProposed) {
        // Round downward to minimize the offer and to maximize the quality.
-        // This has the most impact when takerGets is XRP.
+        // This has the most impact when takerGets is integral.
        auto const takerGets =
            toAmount<TOut>(getAsset(pool.out), nTakerGetsProposed, Number::RoundingMode::Downward);
        return TAmounts<TIn, TOut>{swapAssetOut(pool, takerGets, tfee), takerGets};
@@ -294,7 +294,7 @@ getAMMOfferStartWithTakerPays(

    auto getAmounts = [&pool, &tfee](Number const& nTakerPaysProposed) {
        // Round downward to minimize the offer and to maximize the quality.
-        // This has the most impact when takerPays is XRP.
+        // This has the most impact when takerPays is integral.
        auto const takerPays =
            toAmount<TIn>(getAsset(pool.in), nTakerPaysProposed, Number::RoundingMode::Downward);
        return TAmounts<TIn, TOut>{takerPays, swapAssetIn(pool, takerPays, tfee)};
@@ -313,11 +313,11 @@ getAMMOfferStartWithTakerPays(
 * is equal to LOB quality (in this case AMM offer quality is
 * better than LOB quality) or AMM offer is equal to LOB quality
 * (in this case SPQ is better than LOB quality).
- * Pre-amendment code calculates takerPays first. If takerGets is XRP,
- * it is rounded down, which results in worse offer quality than
- * LOB quality, and the offer might fail to generate.
- * Post-amendment code calculates the XRP offer side first. The result
- * is rounded down, which makes the offer quality better.
+ * Pre-amendment code calculates takerPays first. If takerGets is the
+ * economically coarser integral side, it is rounded down, which results in
+ * worse offer quality than LOB quality, and the offer might fail to generate.
+ * Post-amendment code calculates the economically coarser integral offer side
+ * first. The result is rounded down, which makes the offer quality better.
 *   It might not be possible to match either SPQ or AMM offer to LOB
 * quality. This generally happens at higher fees.
 * @param pool AMM pool balances
@@ -396,10 +396,18 @@ changeSpotPriceQuality(
        return std::nullopt;
    }

-    // Generate the offer starting with XRP side. Return seated offer amounts
-    // if the offer can be generated, otherwise nullopt.
    auto amounts = [&]() {
-        if (isXRP(getAsset(pool.out)))
+        bool const inIntegral = getAsset(pool.in).integral();
+        bool const outIntegral = getAsset(pool.out).integral();
+
+        // Preserve historical behavior for fractional pairs and XRP/IOU-style
+        // one-integral-side pairs. For two integral assets, pick the side whose
+        // minimum unit is economically coarser at this quality.
+        //
+        // Quality::rate() is input units per output unit, so one output unit is
+        // coarser when it costs at least one input unit. Ties use takerGets,
+        // matching the historical XRP-output behavior.
+        if (outIntegral && (!inIntegral || Number(quality.rate()) >= 1))
            return getAMMOfferStartWithTakerGets(pool, quality, tfee);
        return getAMMOfferStartWithTakerPays(pool, quality, tfee);
    }();
--- a/include/xrpl/ledger/helpers/CredentialHelpers.h
+++ b/include/xrpl/ledger/helpers/CredentialHelpers.h
@@ -7,6 +7,7 @@
 #include <xrpl/ledger/ApplyView.h>
 #include <xrpl/ledger/ReadView.h>
 #include <xrpl/protocol/AccountID.h>
+#include <xrpl/protocol/Rules.h>
 #include <xrpl/protocol/STArray.h>
 #include <xrpl/protocol/STLedgerEntry.h>
 #include <xrpl/protocol/STTx.h>
@@ -34,7 +35,7 @@ deleteSLE(ApplyView& view, SLE::ref sleCredential, beast::Journal j);

 // Amendment and parameters checks for sfCredentialIDs field
 NotTEC
-checkFields(STTx const& tx, beast::Journal j);
+checkFields(STTx const& tx, Rules const& rules, beast::Journal j);

 // Accessing the ledger to check if provided credentials are valid. Do not use
 // in doApply (only in preclaim) since it does not remove expired credentials.
--- a/include/xrpl/ledger/helpers/EscrowHelpers.h
+++ b/include/xrpl/ledger/helpers/EscrowHelpers.h
@@ -2,6 +2,7 @@

 #include <xrpl/basics/Log.h>
 #include <xrpl/beast/utility/Journal.h>
+#include <xrpl/beast/utility/instrumentation.h>
 #include <xrpl/ledger/ApplyView.h>
 #include <xrpl/ledger/helpers/AccountRootHelpers.h>
 #include <xrpl/ledger/helpers/MPTokenHelpers.h>
@@ -15,6 +16,7 @@
 #include <xrpl/protocol/Issue.h>
 #include <xrpl/protocol/Keylet.h>
 #include <xrpl/protocol/LedgerFormats.h>
+#include <xrpl/protocol/MPTAmount.h>
 #include <xrpl/protocol/MPTIssue.h>
 #include <xrpl/protocol/Rate.h>
 #include <xrpl/protocol/SField.h>
@@ -241,10 +243,25 @@ escrowUnlockApplyHelper<MPTIssue>(
    auto finalAmt = amount;
    if ((!senderIssuer && !receiverIssuer) && lockedRate != kParityRate)
    {
-        // compute transfer fee, if any
-        auto const xferFee = amount.value() - divideRound(amount, lockedRate, amount.asset(), true);
-        // compute balance to transfer
-        finalAmt = amount.value() - xferFee;
+        if (ctx.view.rules().enabled(fixCleanup3_4_0))
+        {
+            XRPL_ASSERT(
+                lockedRate >= kParityRate,
+                "xrpl::escrowUnlockApplyHelper<MPTIssue> : lockedRate is at least parity");
+            // MPTs are integral, so round the delivered amount down and
+            // charge any fractional transfer fee to the escrowed amount.
+            auto const delivered =
+                mulRatio(amount.mpt(), kParityRate.value, lockedRate.value, false);
+            finalAmt = STAmount(amount.asset(), delivered.value());
+        }
+        else
+        {
+            // compute transfer fee, if any
+            auto const xferFee =
+                amount.value() - divideRound(amount, lockedRate, amount.asset(), true);
+            // compute balance to transfer
+            finalAmt = amount.value() - xferFee;
+        }
    }
    return unlockEscrowMPT(
        ctx.view,
--- a/include/xrpl/ledger/helpers/LendingHelpers.h
+++ b/include/xrpl/ledger/helpers/LendingHelpers.h
@@ -7,6 +7,7 @@
 #include <xrpl/beast/utility/instrumentation.h>
 #include <xrpl/ledger/ApplyView.h>
 #include <xrpl/ledger/ReadView.h>
+#include <xrpl/protocol/AccountID.h>
 #include <xrpl/protocol/Asset.h>
 #include <xrpl/protocol/LedgerFormats.h>  // IWYU pragma: keep
 #include <xrpl/protocol/Protocol.h>
@@ -21,6 +22,7 @@

 #include <cstdint>
 #include <expected>
+#include <optional>
 #include <string_view>
 #include <utility>

@@ -58,6 +60,42 @@ canApplyToBrokerCover(
 bool
 checkLendingProtocolDependencies(Rules const& rules, STTx const& tx);

+/**
+ * The accounts and asset that LoanManage::defaultLoan's fixCleanup3_4_0
+ * freeze/lock exemption applies to.
+ *
+ * `defaultLoan` moves funds from the LoanBroker pseudo-account to the Vault
+ * pseudo-account via `accountSend`. Since neither is the vault asset's
+ * issuer, this is a third-party transfer that transits through the issuer in
+ * two hops (broker -> issuer, issuer -> vault; see
+ * `directSendNoLimitIOU`/`directSendNoLimitMPT`), so the exemption must cover
+ * both the issuer/broker and issuer/vault pairs, not a direct broker/vault
+ * pair. `asset` scopes it further to the vault's own currency/MPT issuance,
+ * so an unrelated one the same accounts happen to hold is still protected.
+ */
+struct LoanDefaultFreezeExemptAccounts
+{
+    AccountID issuer;
+    AccountID broker;
+    AccountID vault;
+    Asset asset;
+};
+
+/**
+ * Resolves the accounts and asset a LoanManage default transaction is
+ * exempt from freeze/lock for.
+ *
+ * @param view Ledger view used to resolve the Loan -> LoanBroker -> Vault
+ * chain.
+ * @param tx The transaction under invariant review.
+ * @return The exempt accounts and asset if `tx` is a `ttLOAN_MANAGE`
+ * transaction with the `tfLoanDefault` flag set, `fixCleanup3_4_0` is
+ * enabled, and the loan/broker/vault objects it references can all be
+ * resolved; `std::nullopt` otherwise.
+ */
+[[nodiscard]] std::optional<LoanDefaultFreezeExemptAccounts>
+getLoanDefaultFreezeExemptAccounts(ReadView const& view, STTx const& tx);
+
 static constexpr std::uint32_t kSecondsInYear = 365 * 24 * 60 * 60;

 Number
--- a/Show More
+++ b/Show More