ECJ -> deprec type feature

Author: Campano

docs/versions/release-notes/v6-3.md

@@ -36,7 +36,20 @@ Deprecations
 
 Deprecated features to be removed in the next releases
 
-> Nothing so far...
+### JDK -> ECJ compiler
+
+The platform now uses the **Eclipse Java Compiler** (ECJ) instead of the JDK compiler.
+
+This is transparent and more efficient. It also allows to deploy the platform on a JRE instead of a JDK keeping Java custom code compilation possible.
+
+> **Reminder**: Java compilation can be explicitly enabled or disabled (`true` by default) using the `server.compiler` JVM argument (`true` by default)
+> which is driven by the `COMPILER` environment variable in our Docker images.
+
+The compiler options can be customized if needed using the `JAVA_COMPILER_OPTIONS` which is provided as `-g -warn:unused,deprecation` in order
+to make more visible (as warnings) all deprecated usages and unused variables/methods in the custom code (not that compilation warnings
+are non blocking but should be fixed).
+
+The list of possible compiler options are described [in the Eclipse documentation](https://help.eclipse.org/latest/index.jsp?topic=%2Forg.eclipse.jdt.doc.user%2Ftasks%2Ftask-using_batch_compiler.htm).
 
 Features
 --------
@@ -84,21 +97,6 @@ Technical
 
 Technical enhancements and features
 
-### ECJ compiler
-
-The platform now uses the **Eclipse Java Compiler** (ECJ) instead of the JDK compiler.
-
-This is transparent and more efficient. It also allows to deploy the platform on a JRE instead of a JDK keeping Java custom code compilation possible.
-
-> **Reminder**: Java compilation can be explicitly enabled or disabled (`true` by default) using the `server.compiler` JVM argument (`true` by default)
-> which is driven by the `COMPILER` environment variable in our Docker images.
-
-The compiler options can be customized if needed using the `JAVA_COMPILER_OPTIONS` which is provided as `-g -warn:unused,deprecation` in order
-to make more visible (as warnings) all deprecated usages and unused variables/methods in the custom code (not that compilation warnings
-are non blocking but should be fixed).
-
-The list of possible compiler options are described [in the Eclipse documentation](https://help.eclipse.org/latest/index.jsp?topic=%2Forg.eclipse.jdt.doc.user%2Ftasks%2Ftask-using_batch_compiler.htm).
-
 ### Server side events
 
 New servlet `/ui/sse` (asynchronous) to push messages from server to clients thru https