diff --git a/.github/workflows/m3h-release-notes-sync.yml b/.github/workflows/m3h-release-notes-sync.yml
new file mode 100644
index 000000000..af893b300
--- /dev/null
+++ b/.github/workflows/m3h-release-notes-sync.yml
@@ -0,0 +1,107 @@
+name: Synchronize M3.H Public Release Notes
+
+on:
+  pull_request:
+    paths:
+      - 'docs/releases/PROCESS_BUS_SIMULATOR_M3H_PUBLIC_20261024.md'
+      - 'scripts/render_m3h_release_notes.py'
+      - '.github/workflows/m3h-release-notes-sync.yml'
+  push:
+    branches: [main]
+    paths:
+      - 'docs/releases/PROCESS_BUS_SIMULATOR_M3H_PUBLIC_20261024.md'
+      - 'scripts/render_m3h_release_notes.py'
+      - '.github/workflows/m3h-release-notes-sync.yml'
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+concurrency:
+  group: m3h-public-release-notes-sync
+  cancel-in-progress: false
+
+jobs:
+  validate-notes:
+    name: Validate product release copy and links
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Render release notes from canonical public documentation
+        run: |
+          python3 scripts/render_m3h_release_notes.py /tmp/m3h-release-notes.md
+          grep -Fq 'ARStack Process Bus Simulator M3.H' /tmp/m3h-release-notes.md
+          grep -Fq 'raw.githubusercontent.com/masarray/arstack61850/main/assets/screenshots/arstack-studio-windows.png' /tmp/m3h-release-notes.md
+
+  update-existing-release-description:
+    name: Refresh M3.H release description only
+    needs: validate-notes
+    if: github.event_name != 'pull_request' && github.ref == 'refs/heads/main'
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+    env:
+      GH_TOKEN: ${{ github.token }}
+      TAG: processbus-sim-m3h-20261024
+    steps:
+      - uses: actions/checkout@v4
+      - name: Render existing stable release description
+        run: python3 scripts/render_m3h_release_notes.py /tmp/m3h-release-notes.md
+
+      - name: Verify release and snapshot immutable assets
+        run: |
+          set -euo pipefail
+          gh api "repos/$GITHUB_REPOSITORY/releases/tags/$TAG" > /tmp/m3h-before.json
+          python3 - <<'PY'
+          import json
+          r=json.load(open("/tmp/m3h-before.json"))
+          assert r["tag_name"]=="processbus-sim-m3h-20261024" and not r["draft"] and not r["prerelease"], "Expected existing public stable M3.H release"
+          expected={
+            "ARStack-ESP32P4-ProcessBus-M3H-firmware.bin",
+            "ARStack-ProcessBus-M3H-win-x64-portable.zip",
+            "ARStack-ProcessBus-M3H-win-x64-setup.exe",
+            "firmware-manifest.json",
+            "SHA256SUMS.txt",
+          }
+          actual={a["name"] for a in r["assets"]}
+          assert actual==expected, f"Release asset inventory changed: {actual ^ expected}"
+          print("PASS: verified existing stable tag and exact five assets")
+          PY
+
+      - name: Update descriptive release notes if changed
+        id: check
+        run: |
+          set -euo pipefail
+          python3 - <<'PY'
+          import json, os
+          previous=json.load(open("/tmp/m3h-before.json"))
+          desired=open("/tmp/m3h-release-notes.md", encoding="utf-8").read()
+          changed=previous.get("body","").strip()!=desired.strip()
+          with open(os.environ["GITHUB_OUTPUT"],"a") as out:
+              out.write(f"changed={'true' if changed else 'false'}\n")
+          print("Release description update required:", changed)
+          PY
+
+      - name: Synchronize only existing release description
+        if: steps.check.outputs.changed == 'true'
+        run: |
+          gh release edit "$TAG" --repo "$GITHUB_REPOSITORY" \
+            --notes-file /tmp/m3h-release-notes.md
+
+      - name: Verify description and asset identities unchanged
+        run: |
+          set -euo pipefail
+          gh api "repos/$GITHUB_REPOSITORY/releases/tags/$TAG" > /tmp/m3h-after.json
+          python3 - <<'PY'
+          import json
+          before=json.load(open("/tmp/m3h-before.json"))
+          after=json.load(open("/tmp/m3h-after.json"))
+          desired=open("/tmp/m3h-release-notes.md", encoding="utf-8").read()
+          assert after.get("body","").strip()==desired.strip(), "Release notes did not match source"
+          for key in ("id", "tag_name", "target_commitish", "draft", "prerelease", "published_at"):
+              assert before[key]==after[key], f"Unexpected release field change: {key}"
+          def assets(r):
+              return sorted((a["id"], a["name"], a["size"], a.get("digest")) for a in r["assets"])
+          assert assets(before)==assets(after), "Release assets changed unexpectedly"
+          print("PASS: release description synchronized, tag and assets preserved")
+          PY
diff --git a/docs/releases/PROCESS_BUS_SIMULATOR_M3H_PUBLIC_20261024.md b/docs/releases/PROCESS_BUS_SIMULATOR_M3H_PUBLIC_20261024.md
index b2acbecae..acbc88bde 100644
--- a/docs/releases/PROCESS_BUS_SIMULATOR_M3H_PUBLIC_20261024.md
+++ b/docs/releases/PROCESS_BUS_SIMULATOR_M3H_PUBLIC_20261024.md
@@ -4,6 +4,8 @@
 
 Generate IEC 61850 Sampled Values and emulate PTP synchronization using **ARStack Studio and ESP32-P4 Ethernet hardware**. This edition combines a 4-current + 4-voltage SV publisher, internal laboratory PTP grandmaster simulation, and hardware-assisted phase synchronization.
 
+![ARStack Studio 4I+4V workspace and waveforms](../../assets/screenshots/arstack-studio-windows.png)
+
 ## What's new
 
 - **SV + PTP in one lab setup** — real Ethernet SV at 4,000 frames/s alongside Layer-2 PTP Announce, Sync and Follow_Up.
diff --git a/scripts/render_m3h_release_notes.py b/scripts/render_m3h_release_notes.py
new file mode 100644
index 000000000..dd38e6694
--- /dev/null
+++ b/scripts/render_m3h_release_notes.py
@@ -0,0 +1,50 @@
+#!/usr/bin/env python3
+"""Render the M3.H public release document into portable GitHub Release notes."""
+from pathlib import Path
+import posixpath
+import re
+import sys
+
+ROOT = Path(__file__).resolve().parents[1]
+SOURCE = ROOT / "docs/releases/PROCESS_BUS_SIMULATOR_M3H_PUBLIC_20261024.md"
+REPO = "masarray/arstack61850"
+BASE = "docs/releases"
+
+def normalize(match):
+    prefix, relative, suffix = match.groups()
+    target = relative.split("#", 1)
+    path = posixpath.normpath(posixpath.join(BASE, target[0]))
+    if path.startswith("../") or path == "..":
+        raise ValueError(f"Relative path escapes repository: {relative}")
+    anchor = "#" + target[1] if len(target) > 1 else ""
+    if not (ROOT / path).is_file():
+        raise FileNotFoundError(f"Broken release-notes link: {relative} → {path}")
+    if prefix.startswith("!["):
+        url = f"https://raw.githubusercontent.com/{REPO}/main/{path}{anchor}"
+    else:
+        url = f"https://github.com/{REPO}/blob/main/{path}{anchor}"
+    return prefix + url + suffix
+
+def main():
+    if len(sys.argv) != 2:
+        raise SystemExit("Usage: render_m3h_release_notes.py output.md")
+    source = SOURCE.read_text(encoding="utf-8")
+    for required in (
+        "163,048", "3,999.884", "smpSynch=2",
+        "a922e9bdba4e57a4e88406eb83344455dd8ff142",
+        "4902e8bf44e78fc55a139ce84a1273f0768ef6fe10000f5d0f85d75d2f6c736e",
+        "ca01424e4102aa65e353737024ebf3258b4d2f614fa60d932c95c353ee228d8f",
+        "61c508e9bf1357eb964d2b817b260b6a0e985446ddd68de1d45d9467e25c4607",
+    ):
+        if required not in source:
+            raise ValueError(f"Missing immutable release evidence: {required}")
+    rendered = re.sub(r"(!?\[[^\]]+\]\()(\.\.?/[^)\s]+)(\))", normalize, source)
+    if re.search(r"!?\[[^\]]+\]\(\.\.?/", rendered):
+        raise ValueError("Unresolved relative release link")
+    dest = Path(sys.argv[1])
+    dest.parent.mkdir(parents=True, exist_ok=True)
+    dest.write_text(rendered, encoding="utf-8")
+    print(f"PASS: verified and rendered {dest}, {len(rendered)} characters")
+
+if __name__ == "__main__":
+    main()