Update README.md

Added v3 deprecation note

README.md

@@ -1,11 +1,18 @@
-# [Sendbird](https://sendbird.com) Chat SDK for iOS (Objective-C)
+# [Sendbird](https://sendbird.com) Chat SDK v3 for iOS (Objective-C)
 
 [![Platform](https://img.shields.io/badge/Platform-iOS-orange.svg)](https://cocoapods.org/pods/SendBirdSDK)
 [![Languages](https://img.shields.io/badge/Language-Objective--C%20%7C%20Swift-orange.svg)](https://github.com/sendbird/sendbird-ios-framework)
 [![CocoaPods](https://img.shields.io/badge/CocoaPods-compatible-green.svg)](https://cocoapods.org/pods/SendBirdSDK)
 [![Carthage compatible](https://img.shields.io/badge/Carthage-compatible-4BC51D.svg?style=flat)](https://github.com/Carthage/Carthage)
 [![Commercial License](https://img.shields.io/badge/License-Commercial-brightgreen.svg)](https://github.com/sendbird/sendbird-ios-framework/blob/master/LICENSE.md)
 
+## Deprecation Note (v3)
+:warning: Please note that Sendbird’s SDK v3 will be deprecated by **July 2023**. You may still use the older SDKs at your choice, but no new updates or bug fixes will be made to SDK v3.
+
+**We recommend clients to plan their migration to SDK v4 as early as possible as there are breaking changes.** We also provide prioritized support for migration and any issues related to v4. SDK v4 provides far richer and robust features in Websocket, Local caching, Polls, Scheduled Messages, Pinned Message, and many more. So try it out now! ([Chat SDK v4](https://github.com/sendbird/sendbird-chat-sdk-ios/))
+
+<br />
+
 ## Table of contents
 
  1. [Introduction](#introduction)
@@ -242,4 +249,4 @@ Sendbird Chat SDK with local caching supports new functionalities such as group
 SyncManager will be deprecated eventually as the embedded local caching serves as the new and better version of it.
 
 For further information, please see our [Docs](https://sendbird.com/docs/chat/v3/ios/guides/local-caching).
-Additionally, migration guide for clients currently using SyncManager will be available soon.
+Additionally, migration guide for clients currently using SyncManager will be available soon.