> ## Documentation Index
> Fetch the complete documentation index at: https://docs.cowagent.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# v2.1.9

> CowAgent 2.1.9: building on the 2.1.8 multi-Agent release with a refined Agent collaboration experience, configurable model lists and model fallback, plus fixes across channel integration, image generation, and voice

🌐 [English](https://docs.cowagent.ai/releases/v2.1.9) | [中文](https://docs.cowagent.ai/zh/releases/v2.1.9)

> This is a refinement release for the [2.1.8 multi-Agent version](https://docs.cowagent.ai/releases/v2.1.8), building on it with a series of improvements and fixes across multi-Agent collaboration, model capabilities, and channel integration.

## 🤝 Multi-Agent Experience

Further polish around using multi-Agent teams:

* **Multi-Agent session selection**: the in-session multi-Agent selector adds a lead-Agent marker that clearly separates the lead Agent from members, while simplifying the view in single-Agent setups.
* **Collaboration fix**: fixed failures when delegating tasks from non-lead Agents in multi-Agent group chats, now correctly identifying member Agents.
* **Member Agent image rendering**: fixed images generated by non-default Agents failing to render on the Web console and desktop client.
* **Group-chat entry**: the desktop **Team** page adds a group-chat entry, so you can start a group session directly from an Agent team.

<img src="https://cdn.jsdelivr.net/gh/zhayujie/cowagent-assets@main/screenshots/en/agent-group-chat-picker.png" alt="Multi-Agent group chat" width="800" />

## 📡 Channel Integration Fixes

Fixed key issues along the console's channel start/stop path for more stable channel integration:

* **Desktop channel integration fix**: fixed channels failing to start in the desktop client.
* **Channel stop fix**: fixed a lost `app_module` lookup during the channel stop flow that caused disconnect errors (a regression introduced by #3141).
* **QQ channel reconnection**: fixed the QQ channel not reconnecting after a silent WebSocket disconnect; it now reconnects automatically.

## 🤖 Model Capabilities

* **Model list configuration**: model providers can now configure a model list, setting the model name, model type, context window, max output, and more. Thanks @alanyz106 (#3146)

<img src="https://cdn.jsdelivr.net/gh/zhayujie/cowagent-assets@main/screenshots/en/model-catalog-config.png" alt="Model list configuration" width="800" />

* **Multiple fallback models**: when the primary model fails, CowAgent now tries an ordered fallback chain in turn, replacing the previous single fallback model. Thanks @alanyz106 (#3125)

<img src="https://cdn.jsdelivr.net/gh/zhayujie/cowagent-assets@main/screenshots/en/model-fallback-chain.png" alt="Multiple fallback models" width="800" />

* **Fallback credential fix**: fixed credential resolution during fallback, which now resolves credentials by the provider actually routed to rather than the global configuration. Thanks @alanyz106 (#3142)
* **New image models**: added `gpt-image-2.5-flare` and `gpt-image-2.5-sunburst`. Thanks @cowagent (#3140)

## 🛠 Improvements & Fixes

* **Config file tolerance**: tolerate a UTF-8 BOM in `config.json`, and stop the pre-login 401 polling to avoid invalid requests before sign-in.
* **Image generation fixes**:
  * fixed Baidu Ernie `IMAGE_CREATE` crashing when unsupported, now returning an error message instead (Thanks @c020627 #3144).
  * fixed Midjourney reply retries not recursing into the send logic correctly (Thanks @c020627 #3151).
* **Voice fix**: fixed silk voice transcoding by first decoding silk into a standalone wav and then re-encoding to mp3, avoiding overwriting the source file (Thanks @c020627 #3149).
* **Media URL classification**: determine media type from the resolved URL path, fixing misclassified media links (Thanks @c020627 #3150).
* **Baidu Translate**: fixed Baidu Translate not reporting the API error after all retries failed (Thanks @c020627 #3147).
* **Background command detection**: restrict `run_in_background` to long-running processes, preventing tasks from being marked complete too early.
* **Tool output truncation**: report the byte-based truncation reason correctly when kept lines are partially truncated (Thanks @c020627 #3137).
* **Web mobile layout**: improved the console layout on mobile.
* **Desktop client**: fixed the multi-Agent team menu not showing.

## 📦 How to Upgrade

* **Source deployment**: run `cow update` for a one-click upgrade, or pull the latest code and restart. See the [upgrade guide](https://docs.cowagent.ai/guide/upgrade).
* **Desktop client**: check for updates and update with one click inside the client, or get the latest version from the [download page](https://cowagent.ai/download/).

**Release date**: 2026.09.14 | [Full Changelog](https://github.com/zhayujie/CowAgent/compare/2.1.8...2.1.9)