diff --git a/back001/README.md b/back001/README.md
index 7aa6539..5aceb05 100644
--- a/back001/README.md
+++ b/back001/README.md
@@ -10,8 +10,9 @@ This project follows a **Modular Monolith** architecture:
 - `workers/*`: Background event consumers/processors.
 
 ## 🛠 Requirements
-- Java 21
+- Java 17
 - Docker + Docker Compose
+  - CI uses a custom `gradle:8.12-jdk17`-based image (see `ci/images/gradle-node/Dockerfile`); match that locally to avoid toolchain download delays.
 
 ## 🚀 Local Run