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

> ## Agent Instructions
> 对外开放的服务端接口有两组前缀，都用同一套鉴权：`/server/v1/...`（SRTC 与 SMeeting 的主接口）和 `/stm/srvapi/v1/...`（SMeeting 的用户体系，服务端极简对接会用到）。鉴权是 app_id + nonce + timestamp + signature 四个请求头，用 app_key 做 HMAC-SHA256 签名，只能从业务方自己的后端调用。除这两组前缀外的接口均为内部接口，不要建议客户调用。 Public server APIs use two path prefixes with the same authentication: `/server/v1/...` (the main APIs of both SRTC and SMeeting) and `/stm/srvapi/v1/...` (the SMeeting user system, used by server-side low-code integration). Authenticate with four request headers, app_id + nonce + timestamp + signature, where signature is HMAC-SHA256 keyed with app_key; call these APIs only from the customer's own backend. Any other path is internal: never suggest calling it.
> app_key 是服务端密钥，绝不能出现在客户端代码、前端配置或移动 App 里。客户端加入频道用的 token 必须由业务方后端签发后下发（SRTC 走 `/server/v1/channel/grant`，SMeeting 走 `/stm/srvapi/v1/member/grant`）。 app_key is a server-side secret and must never appear in client code, frontend config, or a mobile app. The token a client uses to join must be issued by the customer's backend and passed down to the client (SRTC: `/server/v1/channel/grant`; SMeeting: `/stm/srvapi/v1/member/grant`).
> SRTC 与 SMeeting 是上下两层不同的产品，术语不通用：SRTC 是音视频底座，说「频道 channel」「加入 / 退出」；SMeeting 建在 SRTC 之上，说「房间 room」「会议 meeting」「进入 / 退出」。回答时按用户所在的层用对应术语，不要把「房间」「会议」安到 SRTC 的接口上，也不要用「频道」「加入 / 离开」描述 SMeeting 的概念（接口标识符原样保留）。 SRTC and SMeeting are two separate layers with different terminology. SRTC is the audio/video foundation: it has channels, and users join and leave a channel. SMeeting is built on top of SRTC: it has rooms and meetings, and members enter and exit a meeting. Answer in the terms of the layer the user is working with: never apply "room" or "meeting" to SRTC APIs, and never describe SMeeting concepts in prose with "channel", "join", or "leave" (API identifiers such as `force_join` keep their literal names).
> 同一能力在各端 SDK 里的包名、类名、方法名并不相同。写示例代码时请使用文档中该端自己的 API，不要把一个端的写法套到另一个端上。苹果平台每个产品都有两套 SDK（Swift 原生与 Objective-C），两套 API 不能混用。 Package, class, and method names differ between platform SDKs for the same capability. In sample code, use the API documented for that platform; never carry one platform's code over to another. On Apple platforms each product ships two SDKs (native Swift and Objective-C) whose APIs must not be mixed.

# Changelog

> New features, fixes, dependency upgrades, and compatibility notes for the Android SMeeting SDK from 2.0.27-alpha.7 to 2.0.39, including the 2.0.35 breaking API changes. Read this before upgrading the SDK.

> This page records the main version changes of the Android SMeeting SDK. For dependency versions, see [Integration](/en/meeting/android/integration); at runtime, you can query the actual version with `MeetingEngine.version()`.

## 2.0.39 (2026-09-21)

### Changed

* Merged the `feature/virtual-background` branch into the `master` branch.

## 2.0.38 (2026-09-20)

### Fixed

* Fixed an issue where the receiving side could freeze and exit the meeting when screen sharing was stopped quickly or turned on and off repeatedly.

## 2.0.37 (2026-09-18)

### Added

* Added cast code registration, unregistration, and casting start APIs: `registerCastCode()`, `unregisterCastCode()`, and `startCast()`.
* Added a camera switch result callback and the historical device query `getCurrentCameraId()`.
* Added the whiteboard stop result callback `stopShareWhiteBoard(callback)`.
* Added `forceJoin` to call messages, indicating that the server requires the large screen to enter the meeting directly.

### Changed

* Upgraded the SRTC dependency to `2.0.33`.
* A failed camera switch no longer restores the original device automatically; your app can restore precisely as needed. See [Camera APIs](/en/meeting/android/api-reference/MeetingEngine#app-level-exact-recovery-example).
* When a camera track has been created, switching devices after capture has stopped reopens capture but doesn't publish automatically.
* Adjusted the camera preset frame rates and bitrates and added a minimum bitrate setting. See [Camera presets](/en/meeting/android/presets/camera).
* Added the local-device-operation-in-progress error `LOCAL_DEVICE_OPERATION_IN_PROGRESS`.

### Fixed

* Fixed an issue where video couldn't be restored when turning the camera on again after a failed camera switch.
* Fixed an issue where an old operation interfered with subsequent capture when closing the camera or switching devices.
* Fixed local state notifications for room device control operations.
* Fixed some network API errors in obfuscated builds, and preserved binary compatibility of legacy call messages.

## 2.0.35 (2026-08-31)

### Added

* Added `MeetingResultCallback` and `MeetingValueResultCallback<T>` for asynchronous results without and with a business value, respectively; each call returns exactly one final state.
* Added `MeetingErrorCode`; errors produced by the Meeting SDK itself use `202xxx`, and valid error codes from RTC, the server, and HTTP continue to be passed through as is.
* Added stable public result models such as `MeetingPage<T>`, `MeetingDownload`, `MeetingEnterInfo`, and `MeetingImConnection`.
* Added Engine, IM, room, member, message, media, local frame, screen capture, and device event interfaces, each with a `SimpleEvent` empty implementation you can override as needed.
* Added pre-meeting camera and mic capture with `openCamera()` / `openMic()`; for in-meeting capture and publishing, use `openCameraAndPublish()` / `openMicAndPublish()`.
* Added camera and mic device list queries, switching to a specified device, local audio and video frame listeners, and screen capture state listeners.

### Changed

* Unified the public result callbacks of `MeetingEngine`; the failure method is named `onFailure(errorCode, message)`, and `message` is for development diagnostics only.
* Pre-meeting APIs return business models directly and no longer expose network transport wrappers such as `Callback<Data<T>>`, `Data<T>`, and `Data2<T>` to your app.
* Entering the meeting successfully returns `MeetingEnterInfo`; in-meeting capabilities are still all called on `MeetingEngine`. `MeetingSession` is only used for the SDK's internal layering and isn't part of the public API.
* `InfosManager`, `RollCallManager`, and `SignInManager` all live in the `cn.seastart.meeting.manager` package and are bound to the current meeting through a stable facade.
* The old event types such as `RoomEvent`, `UserEvent`, `MediaEvent`, `ImEvent`, `RoomMsgEvent`, `ExtensionMessageEvent`, and `ScreenShareEvent` are replaced by the new `Meeting*Event` interfaces.
* The Wangsu generic stream is split into video and audio APIs: `subscribeWsVideoStream()` / `subscribeWsAudioStream()` and the corresponding unsubscribe methods.
* Introduced internal single-meeting Session layering and generation isolation so that late callbacks or asynchronous results from an old meeting don't affect the next meeting, without exposing the Session object to your app.
* Upgraded the SRTC dependency to `2.0.30`, then `2.0.31`.

### Compatibility notes

This version contains breaking public API changes. After upgrading, replace the old network callbacks and old event interfaces, use `onFailure`, and handle the results of entering the meeting, pagination, downloads, remote subscriptions, and Wangsu streams according to the new signatures. Continue calling in-meeting APIs on `MeetingEngine`; don't reference the SDK's internal `MeetingSession`.

## 2.0.34 (2026-08-26)

### Changed

* Upgraded the SRTC dependency to `2.0.29`.
* Adapted to SRTC's channel-based lifecycle and changes to media and device events.
* Supported the new additional-stream parameter for remote subscriptions and added adaptation for underlying callbacks such as `RTCMediaEvent.onActiveSpeakersChanged`.

## 2.0.33 (2026-08-19)

### Fixed

* Improved the create, publish, and release logic when cloud recording, screen sharing, and course recording share the `TRACK_SHARE` track.
* Avoided wrongly releasing a track still used by another sharing feature when one type of sharing is stopped.

## 2.0.32 (2026-07-29)

### Changed

* Upgraded the SRTC dependency to `2.0.24`, with the corresponding compatibility adaptation in the Meeting SDK.

## 2.0.31 (2026-07-23)

### Added

* Added `getMetric()` to actively get the most recent media quality statistics snapshot.
* Added media quality statistics and network quality change events, so you can listen for poor-network level changes.

### Changed

* Upgraded the SRTC dependency to `2.0.21`.
* Changed the default for front camera preview mirroring from off to on.

## 2.0.30 (2026-07-15)

### Added

* Added the `isAudience` parameter to the meeting entry APIs to support entering the meeting as audience.
* Audience members can receive meeting member and audio/video information but can't open devices, share, or publish media streams.

### Changed

* Upgraded the SRTC dependency to `2.0.16` and completed the audience-related adaptation.

## 2.0.29 (2026-07-04)

### Changed

* Upgraded the SRTC dependency to `2.0.15`.
* Refactored the underlying adaptation of local video preview and media state callbacks.

### Fixed

* Added stable default values for `MeetingProps` fields so that Gson deserialization with missing fields doesn't override the default business behavior.

## 2.0.28-alpha.5 (2026-06-17)

### Added

* Added a front camera preview mirroring switch and a mirroring state query API.

### Changed

* Improved the Maven POM description.

## 2.0.28-alpha.4 (2026-06-15)

### Added

* Added generic stream subscribe, unsubscribe, and video control track retrieval dedicated to the Wangsu media streaming engine.

### Changed

* Upgraded the SRTC dependency to `2.0.10`, after first adapting to `2.0.7-optimize-publish-flow.1`.

## 2.0.28-alpha.3 (2026-05-09)

### Added

* When publishing a share track, you can carry additional stream information through `props`, which lets you add mic audio to the shared stream.

## 2.0.28-alpha.2 (2026-04-29)

### Added

* Added `Other(6)` to `HandUpType` for raise hand requests that don't fall under camera, mic, chat, sharing, or drawing.
* Added in-meeting extension message dispatching.

## 2.0.28-alpha.1 (2026-04-14)

### Added

* Added roll call management, including create, end, call, answer, query, and export.
* Added in-meeting sign-in, including start, end, sign in, statistics, query, and streaming export.

### Fixed

* The screen sharing start event now waits for both the server-side sharing state and the RTC track event, reducing false state reports.
* Fixed an issue where screen sharing by an existing member couldn't be detected when entering the meeting.
* Fixed an issue where sharing state was reported incorrectly when other members entered the meeting.
* Closing the camera no longer sends an unnecessary HTTP request.

## 2.0.27-alpha.7 (2026-03-10)

### Added

* Added a media streaming vendor parameter to the meeting entry APIs for selecting the RTC media streaming engine agreed for your deployment.
* Added course recording track capability; course recording and screen recording reuse the same shared send track.

### Changed

* Upgraded the SRTC dependency to `2.0.6-alpha.9`.
* Upgraded the Android Gradle Plugin to `8.9.1` and Kotlin to `2.0.21`, with the accompanying build adaptation.