docs: add notifications-improvements report for v3.1.0

docs/features/index-management/index-management.md

@@ -180,6 +180,7 @@ PUT _plugins/_rollup/jobs/sample_rollup
 
 | Version | PR | Description |
 |---------|-----|-------------|
+| v3.1.0 | [#1413](https://github.com/opensearch-project/index-management/pull/1413) | Removed unnecessary user notifications for version conflict exception |
 | v3.0.0 | [#1198](https://github.com/opensearch-project/index-management/pull/1198) | Adding unfollow action in ISM for CCR |
 | v3.0.0 | [#1377](https://github.com/opensearch-project/index-management/pull/1377) | Target Index Settings for rollup |
 | v3.0.0 | [#1388](https://github.com/opensearch-project/index-management/pull/1388) | CVE fix: logback-core upgrade |
@@ -204,8 +205,11 @@ PUT _plugins/_rollup/jobs/sample_rollup
 - [Issue #1075](https://github.com/opensearch-project/index-management/issues/1075): ISM listener blocking Cluster Applier thread
 - [Issue #1213](https://github.com/opensearch-project/index-management/issues/1213): Feature request for mixed rollup/non-rollup search
 
+- [Issue #1371](https://github.com/opensearch-project/index-management/issues/1371): False positive notifications in Snapshot Management
+
 ## Change History
 
+- **v3.1.0** (2026-01-10): Fixed false positive notifications in Snapshot Management by suppressing user notifications for internal VersionConflictEngineException errors
 - **v3.0.0** (2025-05-06): Added ISM unfollow action for CCR, rollup target index settings, CVE fixes, Java Agent migration
 - **v2.18.0** (2024-11-05): Added `plugins.rollup.search.search_source_indices` setting to allow searching non-rollup and rollup indices together, UX improvements (refresh buttons, section header styling), transform API input validation, fixed snapshot status detection, fixed snapshot policy button reload, fixed data source initialization
 - **v2.17.0** (2024-09-17): Performance optimization for skip execution check using cluster service instead of NodesInfoRequest, security integration test fixes

docs/releases/v3.1.0/features/index-management/notifications-improvements.md

@@ -0,0 +1,92 @@
+# Notifications Improvements
+
+## Summary
+
+This bugfix eliminates false positive notifications in Snapshot Management by suppressing user notifications for internal `VersionConflictEngineException` errors that occur during concurrent snapshot operations. Users no longer receive misleading error notifications for race conditions that don't affect actual snapshot functionality.
+
+## Details
+
+### What's New in v3.1.0
+
+The Snapshot Management state machine now handles `VersionConflictEngineException` gracefully by logging the error instead of throwing an exception that triggers user notifications.
+
+### Technical Changes
+
+#### Problem Background
+
+When a manual snapshot policy runs, it creates and deletes snapshots based on configured cron jobs. These operations update state in the `.ism-config` system index. Due to race conditions during concurrent operations:
+
+1. A snapshot deletion starts and holds a lock on the system index
+2. Another snapshot creation begins while the deletion is in progress
+3. When the deletion completes, it fails to update metadata due to version conflict
+4. Previously, this triggered a notification to users despite the snapshot operation succeeding
+
+```mermaid
+sequenceDiagram
+    participant User
+    participant SM as Snapshot Management
+    participant ISM as .ism-config Index
+    participant Notif as Notifications
+
+    SM->>ISM: Start snapshot deletion (seqNo=100)
+    SM->>ISM: Start snapshot creation (seqNo=100)
+    ISM-->>SM: Creation succeeds (seqNo=101)
+    ISM-->>SM: Deletion metadata update fails (VersionConflict)
+    Note over SM: Before: Exception thrown
+    SM->>Notif: Send error notification
+    Notif->>User: False alarm notification
+
+    Note over SM: After v3.1.0: Exception handled
+    SM->>SM: Log error, continue
+    Note over User: No false alarm
+```
+
+#### Code Changes
+
+The fix modifies `SMStateMachine.kt` to catch and handle `VersionConflictEngineException` separately:
+
+```kotlin
+} catch (ex: Exception) {
+    val unwrappedException = ExceptionsHelper.unwrapCause(ex) as Exception
+    if (unwrappedException is VersionConflictEngineException) {
+        // Don't throw the exception
+        log.error("Version conflict exception while updating metadata.", ex)
+        return
+    }
+    // Other exceptions still trigger notifications
+    val smEx = SnapshotManagementException(ExceptionKey.METADATA_INDEXING_FAILURE, ex)
+    log.error(smEx.message, ex)
+    throw smEx
+}
+```
+
+#### Changed Files
+
+| File | Changes |
+|------|---------|
+| `SMStateMachine.kt` | Added exception handling for `VersionConflictEngineException` |
+| `SMStateMachineTests.kt` | Added unit tests for graceful handling and exception propagation |
+
+### Migration Notes
+
+No migration required. This is a transparent bugfix that improves notification accuracy.
+
+## Limitations
+
+- The underlying race condition still exists; only the notification behavior is changed
+- A future enhancement (noted in TODO) could extract seqNo from the exception and retry the metadata update
+
+## Related PRs
+
+| PR | Description |
+|----|-------------|
+| [#1413](https://github.com/opensearch-project/index-management/pull/1413) | Removed unnecessary user notifications for version conflict exception |
+
+## References
+
+- [Issue #1371](https://github.com/opensearch-project/index-management/issues/1371): Eliminate False Positive Notifications in Manual Snapshot Policy
+- [Snapshot Management Documentation](https://docs.opensearch.org/3.0/tuning-your-cluster/availability-and-recovery/snapshots/snapshot-management/)
+
+## Related Feature Report
+
+- [Index Management](../../../features/index-management/index-management.md)

docs/releases/v3.1.0/index.md

@@ -97,6 +97,10 @@
 
 - [Flow Framework Dependencies](features/flow-framework/flow-framework-dependencies.md) - Conditional DynamoDB client dependency and data summary with log pattern agent template
 
+### Index Management
+
+- [Notifications Improvements](features/index-management/notifications-improvements.md) - Fix false positive notifications in Snapshot Management for version conflict exceptions
+
 ### Dashboards Assistant
 
 - [Dashboard Assistant CI Fixes](features/dashboards-assistant/dashboard-assistant-ci-fixes.md) - Fix CI failures due to path alias babel configuration changes