Telegram has added a new ability, to import chat history from WhatsApp. This means you won’t lose the chat history while switching to telegram WhatsApp.
On iOS, the new version with version 7.4 has arrived in iOS. There is no update for importing chats in Andriod, chats from WhatsApp and KakaoTalk can be imported to Telegram without any hesitation. Almost every WhatsApp user has registered himself in telegram too. As the new feature came into the market, the user base also increased and the service now broadcasting over 500 million active users worldwide.
The import process works on a chat-by-chat basis but appears to work for both individual and group conversations. Open the relevant conversation, and tap the group or contact name from the top of the chat to open its info screen. From there, the “Export Chat” option opens the iOS Share Sheet, where you’ll see the option to select Telegram. Then, just select telegram to import that chat.