diff --git a/.github/workflows/beta-release.yml b/.github/workflows/beta-release.yml
index 9e5dcbee..167f3cb2 100644
--- a/.github/workflows/beta-release.yml
+++ b/.github/workflows/beta-release.yml
@@ -16,6 +16,10 @@ on:
         description: "Optional downloader code footer"
         required: false
         type: string
+      custom_release_notes:
+        description: "Optional full Markdown release notes. When set, it replaces generated notes entirely."
+        required: false
+        type: string
       extra_notes:
         description: "Optional extra bullet lines, one per line"
         required: false
@@ -85,9 +89,17 @@ jobs:
 
       - name: Preview beta release
         if: ${{ inputs.dry_run }}
+        env:
+          CUSTOM_RELEASE_NOTES: ${{ inputs.custom_release_notes }}
         run: |
+          CUSTOM_NOTES_ARG=""
+          if [ -n "$CUSTOM_RELEASE_NOTES" ]; then
+            printf '%s' "$CUSTOM_RELEASE_NOTES" > "$RUNNER_TEMP/custom-release-notes.md"
+            CUSTOM_NOTES_ARG="--custom-notes-file $RUNNER_TEMP/custom-release-notes.md"
+          fi
           python3 scripts/release_beta.py "${{ inputs.version }}" \
             --dry-run \
+            $CUSTOM_NOTES_ARG \
             --downloader-code "${{ inputs.downloader_code }}" \
             --extra-notes "${{ inputs.extra_notes }}"
 
@@ -102,8 +114,15 @@ jobs:
         if: ${{ !inputs.dry_run }}
         env:
           GH_TOKEN: ${{ github.token }}
+          CUSTOM_RELEASE_NOTES: ${{ inputs.custom_release_notes }}
         run: |
+          CUSTOM_NOTES_ARG=""
+          if [ -n "$CUSTOM_RELEASE_NOTES" ]; then
+            printf '%s' "$CUSTOM_RELEASE_NOTES" > "$RUNNER_TEMP/custom-release-notes.md"
+            CUSTOM_NOTES_ARG="--custom-notes-file $RUNNER_TEMP/custom-release-notes.md"
+          fi
           python3 scripts/release_beta.py "${{ inputs.version }}" \
             --publish \
+            $CUSTOM_NOTES_ARG \
             --downloader-code "${{ inputs.downloader_code }}" \
             --extra-notes "${{ inputs.extra_notes }}"
diff --git a/scripts/release_beta.py b/scripts/release_beta.py
index 1063e24b..ccf3869a 100755
--- a/scripts/release_beta.py
+++ b/scripts/release_beta.py
@@ -224,7 +224,11 @@ def build_release_notes(
     downloader_code: str | None,
     extra_notes: str | None,
     extra_lines: list[str],
+    custom_notes: str | None,
 ) -> str:
+    if custom_notes and custom_notes.strip():
+        return custom_notes.strip() + "\n"
+
     normalized = [
         note
         for note in (normalize_subject(subject) for subject in commit_subjects(previous_tag))
@@ -381,6 +385,14 @@ def parse_args() -> argparse.Namespace:
         )
     )
     parser.add_argument("version", help="Target versionName, for example 0.4.19-beta")
+    parser.add_argument(
+        "--custom-notes",
+        help="Full release notes markdown. When set, it replaces the generated notes entirely.",
+    )
+    parser.add_argument(
+        "--custom-notes-file",
+        help="Path to a markdown file whose contents replace the generated release notes entirely.",
+    )
     parser.add_argument(
         "--downloader-code",
         help="Optional release-note footer value for the downloader code",
@@ -419,6 +431,8 @@ def main() -> int:
 
     if args.dry_run and args.publish:
         raise SystemExit("Use either --dry-run or --publish, not both.")
+    if args.custom_notes and args.custom_notes_file:
+        raise SystemExit("Use either --custom-notes or --custom-notes-file, not both.")
 
     if not VERSION_PATTERN.match(args.version):
         raise SystemExit(f"Invalid version format: {args.version}")
@@ -427,12 +441,16 @@ def main() -> int:
     current_version_name, current_version_code = parse_versions(original_contents)
     next_version_code = current_version_code + 1
     previous_tag = last_tag()
+    custom_notes = args.custom_notes
+    if args.custom_notes_file:
+        custom_notes = Path(args.custom_notes_file).read_text(encoding="utf-8")
     notes = build_release_notes(
         previous_tag=previous_tag,
         max_items=args.max_items,
         downloader_code=args.downloader_code,
         extra_notes=args.extra_notes,
         extra_lines=args.extra_line,
+        custom_notes=custom_notes,
     )
     notes_path = write_release_notes(args.version, notes)