The service for BlackBerry and Nokia operating systems will end by June this year.
Instant messaging app WhatsApp has pulled support for older versions of iOS and Android operating systems, blocking the chat app for millions.
The platforms no longer supported by the Facebook-owned company include Android 2.1 and Android 2.2, Windows Phone 7 and iPhone 3GS/iOS 6.
The move is part of the company’s plans to make the service available on new operating systems in order to introduce enhanced features and security.
Whatsapp said in a blog: “Earlier this week WhatsApp turned seven years old. It has been an amazing journey and in the coming months we’re putting an even greater emphasis on security features and more ways to stay in touch with the people that you care about.”
The messaging app provider plans to end the service for other platforms by 30 June 2017. They include BlackBerry OS and BlackBerry 10, Nokia S40 and Nokia Symbian S60.
The company said: “These platforms don’t offer the kind of capabilities we need to expand our app’s features in the future.”
The company recommended users with the affected mobile devices to upgrade to a newer Android running OS 2.3+, a Windows Phone 8+, or an iPhone running iOS 7+ before the end of 2016 to continue using WhatsApp.
“Once you have one of these devices, simply install WhatsApp and verify your phone number on the new device to continue using WhatsApp,” said WhatsApp.
“Keep in mind that WhatsApp can only be activated with one phone number on one device at a time.”
Also, the firm is not offering any option for the users to transfer their chat history between platforms.
But it will provide an option to send chat history attached to an email.
In February last year, the firm said: “When we started WhatsApp in 2009, people’s use of mobile devices looked very different from today. The Apple App Store was only a few months old. About 70% of smartphones sold at the time had operating systems offered by BlackBerry and Nokia.
“Mobile operating systems offered by Google, Apple and Microsoft – which account for 99.5% of sales today – were on less than 25% of mobile devices sold at the time.”