diff --git a/README.md b/README.md
index b366f12..693eb73 100644
--- a/README.md
+++ b/README.md
@@ -4,7 +4,7 @@
 > **Test & Evaluation (T&E)** programme management — with a FastAPI backend,
 > React frontend, and a 142-assertion SQL test suite.
 
-[![PostgreSQL](https://img.shields.io/badge/PostgreSQL-17%2B-336791?logo=postgresql&logoColor=white)](https://www.postgresql.org/)
+[![PostgreSQL](https://img.shields.io/badge/PostgreSQL-16%2B-336791?logo=postgresql&logoColor=white)](https://www.postgresql.org/)
 [![Python](https://img.shields.io/badge/Python-3.10%2B-3776AB?logo=python&logoColor=white)](https://www.python.org/)
 [![FastAPI](https://img.shields.io/badge/FastAPI-0.140%E2%80%930.141-009688?logo=fastapi&logoColor=white)](https://fastapi.tiangolo.com/)
 [![React](https://img.shields.io/badge/React-19-61DAFB?logo=react&logoColor=white)](https://react.dev/)
@@ -16,7 +16,7 @@
 ## Status
 
 - Actively developed by a single maintainer.
-- PostgreSQL is the only supported engine for now. The other five engine
+- PostgreSQL 16 or later is the only supported engine for now. The other five engine
   adapters in `build/adapters/` are kept but not maintained
   ([ADR-0001](docs/adr/0001-postgresql-first.md)).
 - CI (`.github/workflows/quality-gate.yml`) runs on every push to `main` and on pull requests:
@@ -359,4 +359,4 @@ MIT — see [LICENSE](LICENSE) for full text.
 
 ## Acknowledgements
 
-Built with [PostgreSQL](https://www.postgresql.org/) 17+, [FastAPI](https://fastapi.tiangolo.com/), [React 19](https://react.dev/), and [Lovable](https://lovable.dev/).
+Built with [PostgreSQL](https://www.postgresql.org/) 16+, [FastAPI](https://fastapi.tiangolo.com/), [React 19](https://react.dev/), and [Lovable](https://lovable.dev/).
diff --git a/docs/QUICKSTART.md b/docs/QUICKSTART.md
index 6a3240e..981b3ac 100644
--- a/docs/QUICKSTART.md
+++ b/docs/QUICKSTART.md
@@ -12,7 +12,7 @@ For architecture and rationale see `docs/ARCHITECTURE.md`, `docs/VCRM.md`, and
 
 | Requirement | Version | Notes |
 |---|---|---|
-| PostgreSQL | 17 or 18 | PG 18 recommended — installs on port 5433 by default |
+| PostgreSQL | 16 or later | CI tests PostgreSQL 16. The walkthrough below uses PostgreSQL 18 on port 5433 |
 | Python | 3.10+ | Must be on PATH |
 | Node.js | 22.12+ | Required for the React frontend (TanStack Start needs >=22.12) |
 | Git Bash | Any | Required for bash scripts on Windows |