Docs: Added v0.22.0 release notes. (#11202)

### What problem does this PR solve?

### Type of change

- [x] Documentation Update

docs/release_notes.md

@@ -7,6 +7,42 @@ slug: /release_notes
 
 Key features, improvements and bug fixes in the latest releases.
 
+## v0.22.0
+
+Released on November 12, 2025.
+
+### Breaking Changes
+
+:::danger IMPORTANT
+From this release onwards, we ship only the slim edition (without embedding models) Docker image and no longer append the `-slim` suffix to the image tag.
+:::
+
+### New Features
+
+- Dataset:
+  - Supports data synchronization from five online sources (AWS S3, Google Drive, Notion, Confluence, and Discord).
+  - RAPTOR can be built across an entire dataset or on individual documents.
+- Ingestion pipeline: Supports [Docling document parsing](https://github.com/docling-project/docling) in the **Parser** component.
+- Launches a new administrative Web UI dashboard for graphical user management and service status monitoring.
+- Agent:
+  - Supports structured output.
+  - Supports metadata filtering in the **Retrieval** component.
+  - Introduces a **Variable aggregator** component with data operation and session variable definition capabilities.
+
+### Improvements
+
+- Agent: Supports visualizing previous components' outputs in the **Await Response** component.
+- Revamps the model provider page.
+- Upgrades RAGFlow's document engine Infinity to v0.6.5.
+
+### Added Models
+
+- Kimi-K2-Thinking
+
+### New agent templates
+
+- Interactive Agent, incorporates real-time user feedback to dynamically optimize Agent output.
+
 ## v0.21.1
 
 Released on October 23, 2025.