diff --git a/periscope/dependency/frontend/content/changelog.md b/periscope/dependency/frontend/content/changelog.md
index 8d81a86..9178856 100644
--- a/periscope/dependency/frontend/content/changelog.md
+++ b/periscope/dependency/frontend/content/changelog.md
@@ -2,6 +2,14 @@
 
 What's new in Periscope.
 
+## 2.51.0 — 2026-09-20 — Native Settings, FastAPI app, leftover routers
+
+`config.py`, `main.py`, `pipeline_worker.py`, and leftover HTTP routers (`admin`, `contact`, `deps`, `feedback`, `pipeline`, `projects`, `reports`, `survey`) are original Periscope code in `periscope/src`. Inherited copies stay on disk. `routers/auth.py` is unchanged. JWT middleware remains leftover. Frontend product chrome is still the Docker overlay (src pages already win for library/PCB/placement/sign-in). Pad≠Via unchanged.
+
+- [New] Settings rewrite: DeepSeek-only routing; Anthropic env names coerced or ignored.
+- [New] FastAPI entry + worker rewrite; worker still must not import `backend.main`.
+- [New] Project/pipeline/report/admin HTTP surface rewrite.
+
 ## 2.50.0 — 2026-09-20 — Native analysis pipeline and leftover checks
 
 `pipeline.py`, `projects.py`, `email.py`, `purple_parts.py`, and leftover analysis modules (`resolve_passives`, `derating`, `bom_summary`, `pin_mux_check`, `led_current_check`, `pin_function_tokens`, plus `validate`/`validation_tools` aliases) are original Periscope code in `periscope/src`. Inherited copies stay on disk. Live path is still `job_workspace` / `datasheet_extract` / `review_session`. Auth untouched. Pad≠Via unchanged.