# Migrate from Voice SDK 3.x (/en/realtime-media/voice/reference/migration-guide/unreal)

> For AI agents: see the complete documentation index at [llms.txt](/llms.txt).

This page introduces the main steps to upgrade the [Video SDK for Unreal Engine](https://github.com/AgoraIO-Community/Agora-Unreal-SDK) from v3.x (v3.5.0.4) to v4.x, as well as the related changes.

    ### 1. Integrate the SDK [#1-integrate-the-sdk-5]

    To integrate Video SDK for Unreal Engine v4.2.1 into your project, see [SDK quickstart](../index.mdx).

    ### 2. Update the Agora code in your app [#2-update-the-agora-code-in-your-app-5]

    This section explains the main changes between Video SDK for Unreal Engine v3.x and v4.x. Use this information to upgrade your app.

    **Basic changes**

    Video SDK for Unreal Engine v4.x is based on Video SDK for C++ v4.x. First follow the steps in [Migrate from Video SDK 3.x](migration-guide?platform=windows) for Windows.

    **Other changes**

    * The `agora::rtc::ue4::AgoraRtcEngine*` interface class is renamed to `agora::rtc::ue::RtcEngineProxy*`. Rename `agora::rtc::ue4::AgoraRtcEngine*` to `agora::rtc::ue::RtcEngineProxy*` in your app.
    * The v4.x SDK simplifies the implementation steps for video rendering. The `OnTick` function is handled by the `VideoRenderingManager`. Remove all code related to `OnTick` from your project files.
    * To directly import Video SDK for Unreal Engine v4.x objects, include `AgoraPluginInterface.h` into all your classes. You may also need `AgoraPlugin\Private\AgoraCppPlugin\include\AgoraHeaderBase.h`.