Update docs/release-notes/breaking-changes.md

Co-authored-by: Rob Bavey <rob.bavey@elastic.co>

Author: edmocosta

docs/release-notes/breaking-changes.md

@@ -22,7 +22,7 @@ Before you upgrade, carefully review the Logstash breaking changes and take the
 ::::{dropdown} JDK17 not supported
 :name: jdk-17-support-drop
 
-JDK21 is the minimum version of the JDK required to run {{ls}}.
+JDK 21 is now the minimum version of the JDK required to run {{ls}}. This release upgrades JRuby from 9.x to 10.x, which requires JDK 21 or higher.
 For the best experience, we still recommend running {{ls}} using the bundled-jdk.
 See [Logstash JVM requirements](/reference/getting-started-with-logstash.md#ls-jvm)
 for details [#19010](https://github.com/elastic/logstash/pull/19010).