docs: align compatibility messaging (Java 17+, Spring Boot 3.4/3.5) and update badges/cover

Author: bsayli

CONTRIBUTING.md

@@ -7,8 +7,8 @@ This repository provides a **contract-first, generics-aware OpenAPI platform**,
 
 Built with:
 
-* Java 21
-* Spring Boot 3.5.x
+* Java 17+
+* Spring Boot 3.4.x, 3.5.x
 * OpenAPI Generator 7.x
 
 > Be kind. Be constructive. See our [Code of Conduct](./CODE_OF_CONDUCT.md).
@@ -76,7 +76,7 @@ git checkout -b feature/scope-short-title
 
 ### Prerequisites
 
-* Java 21
+* Java 17+ (21 recommended)
 * Maven 3.9+
 
 ### Build (core platform)
@@ -137,6 +137,8 @@ Notes:
 
 ## Architecture principles (important)
 
+> These are not guidelines — they are invariants.
+
 This project follows strict boundaries:
 
 ### 1. Contract is the source of truth

README.md

@@ -4,8 +4,8 @@
 [![Release](https://img.shields.io/github/v/release/blueprint-platform/openapi-generics?label=release&logo=github)](https://github.com/blueprint-platform/openapi-generics/releases/latest)
 [![CodeQL](https://github.com/blueprint-platform/openapi-generics/actions/workflows/codeql.yml/badge.svg)](https://github.com/blueprint-platform/openapi-generics/actions/workflows/codeql.yml)
 [![codecov](https://codecov.io/gh/blueprint-platform/openapi-generics/branch/main/graph/badge.svg)](https://codecov.io/gh/blueprint-platform/openapi-generics)
-[![Java](https://img.shields.io/badge/Java-21-red?logo=openjdk)](https://openjdk.org/projects/jdk/21/)
-[![Spring Boot](https://img.shields.io/badge/Spring%20Boot-3.5.x-green?logo=springboot)](https://spring.io/projects/spring-boot)
+[![Java](https://img.shields.io/badge/Java-17%2B-red?logo=openjdk)](https://openjdk.org/)
+[![Spring Boot](https://img.shields.io/badge/Spring%20Boot-3.4.x%20%7C%203.5.x-green?logo=springboot)](https://spring.io/projects/spring-boot)
 [![OpenAPI Generator](https://img.shields.io/badge/OpenAPI%20Generator-7.x-blue?logo=openapiinitiative)](https://openapi-generator.tech/)
 [![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](LICENSE)
 
@@ -109,14 +109,15 @@ Inherit the parent:
 
 That’s it.
 
-Everything else in this repository is a **reference implementation of this setup**.
+Everything else in this repository is a **reference implementation of this setup**.  
+For detailed setup and advanced usage, see the [Adoption Guides](#adoption-guides).
 
 ---
 
 ## ⚡ Quick Start (2 minutes)
 
-> Requires Spring Boot 3.4+ and OpenAPI Generator 7.x
-> See module documentation for compatibility details.
+> Requires Java 17+, Spring Boot 3.4.x / 3.5.x, and OpenAPI Generator 7.x  
+> See module documentation for full compatibility details.
 
 This repository demonstrates a **contract-first, generics-aware API lifecycle**.
 

docs/images/cover/cover.html

@@ -166,25 +166,25 @@ <h1 class="title">
     </div>
 
     <div class="badges" aria-label="Tech badges">
-        <span class="badge green" title="Spring Boot 3.5.x">
+        <span class="badge green" title="Spring Boot 3.4.x / 3.5.x">
           <svg viewBox="0 0 24 24" fill="none"><path d="M12 3l9 5v8l-9 5-9-5V8l9-5z" fill="#16a34a"/></svg>
-          Spring Boot&nbsp;3.5.x
+          Spring Boot&nbsp;3.4.x&nbsp;|&nbsp;3.5.x
         </span>
       <span class="badge blue" title="OpenAPI Generator 7.x">
           <svg viewBox="0 0 24 24" fill="none"><circle cx="12" cy="12" r="10" fill="#2563eb"/></svg>
           OpenAPI Generator&nbsp;7.x
         </span>
-      <span class="badge yellow" title="Java 21">
+      <span class="badge yellow" title="Java 17+">
           <svg viewBox="0 0 24 24" fill="none"><path d="M4 18h16M6 14h12M8 10h8M10 6h4" stroke="#a16207" stroke-width="2" stroke-linecap="round"/></svg>
-          Java&nbsp;21
+          Java&nbsp;17+
         </span>
     </div>
   </div>
 
   <div class="footer">
     <span>One Contract. Zero Drift.</span>
     <span class="sep">•</span>
-    <span>github.com/bsayli</span>
+    <span>github.com/blueprint-platform/openapi-generics</span>
   </div>
 </section>
 </body>

docs/images/cover/cover.png

@@ -15,10 +15,11 @@ nav_order: 1
 
 - [Why this exists](#why-this-exists)
 - [What you actually do](#what-you-actually-do)
-- [⚡ Quick Start](#-quick-start)
+- [Quick Start](#-quick-start)
     - [1. Server (producer)](#1-server-producer)
     - [2. Client (consumer)](#2-client-consumer)
 - [Result](#result)
+- [Compatibility Matrix](#-compatibility-matrix)
 - [Proof — Generated Client (Before vs After)](#proof--generated-client-before-vs-after)
     - [Before (default OpenAPI behavior)](#before-default-openapi-behavior)
     - [After (contract-aligned generation)](#after-contract-aligned-generation)
@@ -29,7 +30,7 @@ nav_order: 1
 - [Why this matters](#why-this-matters)
 - [Mental model](#mental-model)
 - [Next steps](#next-steps)
-- [🔗 References & External Links](#-references--external-links)
+- [References & External Links](#-references--external-links)
 - [Final note](#final-note)
 
 ---
@@ -125,6 +126,26 @@ The exact same contract type flows from server to client.
 
 ---
 
+## 🔧 Compatibility Matrix
+
+This platform is designed for a **stable, production-proven stack**.
+
+### Runtime (Server)
+
+| Component           | Supported Versions        |
+|--------------------|--------------------------|
+| Java               | 17+                      |
+| Spring Boot        | 3.4.x, 3.5.x             |
+| springdoc-openapi  | 2.8.x (WebMvc starter)   |
+
+### Build-time (Client Generation)
+
+| Component           | Supported Versions |
+|--------------------|-------------------|
+| OpenAPI Generator  | 7.x               |
+
+---
+
 ## Proof — Generated Client (Before vs After)
 
 ### Before (default OpenAPI behavior)