Add Cloud Serverless breaking change details

release-notes/elastic-cloud-serverless/breaking-changes.md

@@ -8,12 +8,39 @@
 
 ## August 25, 2025 [elastic-cloud-serverless-08252025-breaking]
 
-* Allows partial results by default in {{esql}} [#125060](https://github.com/elastic/elasticsearch/pull/125060)
+:::{dropdown} Allows partial results by default in {{esql}}
+
+In earlier versions of {{es}}, {{esql}} would fail the entire query if it encountered any error.
+{{esql}} now returns partial results instead of failing when encountering errors.
+
+**Impact:**
+
+Callers should check the `is_partial` flag returned in the response to determine if the result is partial or complete.
+If returning partial results is not desired, this option can be overridden per request via an `allow_partial_results` parameter in the query URL or globally via the cluster setting `esql.query.allow_partial_results`.
+
+For more information, view [#125060](https://github.com/elastic/elasticsearch/pull/125060).
+:::
 
 ## August 11, 2025 [elastic-cloud-serverless-08112025-breaking]
 
-* Improves advanced settings management APIs privilege checks [#230067]({{kib-pull}}230067)
+:::{dropdown} Improves advanced settings management APIs privilege checks
+
+Roles with explicit read access to advanced settings but all access to `SavedObjectManagement` can no longer update settings via the internal advanced settings API.
+This update enforces explicit privileges instead of relying on saved object security checks.
+
+For more information, view [#230067]({{kib-pull}}230067).
+:::
 
 ## June 23, 2025 [serverless-changelog-06232025]
 
-* {{esql}}: Disallows mixed quoted/unquoted patterns in `FROM` commands [#127636]({{es-pull}}127636)
+:::{dropdown} Disallows mixed quoted/unquoted patterns in FROM
+
+Previously, the {{esql}} grammar allowed users to individually quote constituent strings in index patterns such as `"remote_cluster":"index_name"`. This would allow users to write complex malformed index patterns that often slip through grammar and the subsequent validation.
+This could result in runtime errors that can be misleading.
+This change simplifies the grammar to early reject such malformed index patterns at the parsing stage, allowing users to write simpler queries and see more relevant and meaningful errors.
+
+**Impact:**
+
+Users can write queries with simpler index patterns and see more meaningful and relevant errors.
+For more information, view [#127636]({{es-pull}}127636).
+:::