resole review comments

markdown/RTC 4.x/release-notes/en-US/framework/release_bluerprint_ng.md

@@ -1,6 +1,6 @@
 ## v4.2.1 
 
-v4.2.1 was released on October xx, 2023. 
+This version was released on October xx, 2023. 
 
 This is the first release of Video SDK for Unreal Blueprint.
 

markdown/RTC 4.x/release-notes/en-US/framework/release_unreal_ng.md

@@ -1,11 +1,12 @@
 ## v4.2.1 
 
-This version was released on October xx, 2023.
+This version was released on October xx, 2023. 
 
-**Compatibility changes**
+**Features**
 
-If you have already integrated the 3.x version of the SDK and wish to upgrade to this version, please refer to [Migration Guide](https://github.com/AgoraIO-Extensions/Agora-Unreal-RTC-SDK/blob/main/Migration%20Guide.md) for upgrade instructions.
+The SDK is designed by Agora for developers who use Unreal, aiming to provide a simple and user-friendly real-time interactive solution for Unreal Engine users. 
 
+The SDK provides a powerful set of C++ APIs, allowing developers to easily build games or apps with real-time interactive features. It can also leverage the powerful graphics engine functionality of Unreal Engine to add various visual effects and interactive performance to the app, providing users with a more immersive experience.
 
 **Reference**
 
@@ -18,3 +19,5 @@ To integrate real-time engagement functionality into your app using Agora SDK fo
 - [API Reference]()
 
 Agora provides the open source [example project](https://github.com/AgoraIO-Extensions/Agora-Unreal-RTC-SDK/tree/main/Agora-Unreal-SDK-CPP-Example) on GitHub for your reference.
+
+<div class="alert info">If you have already integrated the 3.x version of the SDK and wish to upgrade to this version, please refer to [Migration Guide](https://github.com/AgoraIO-Extensions/Agora-Unreal-RTC-SDK/blob/main/Migration%20Guide.md) for upgrade instructions.</div>