The announcement comes after a warning earlier this year that the Facebook-owned company would be pulling support for older models, and that the deadline to upgrade was fast approaching.
The same blog post was then updated to say some phones would be supported until June 30, 2017, while the service would be discontinued on others by the end of this year.
The blog says: “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 per cent of smartphones sold at the time had operating systems offered by BlackBerry and Nokia.
“As we look ahead to our next seven years, we want to focus our efforts on the mobile platforms the vast majority of people use.”
Those using certain handsets will have to buy new ones if they want to use the world’s most popular messaging app, which has a billion users globally.
“While these mobile devices have been an important part of our story, they don’t offer the kind of capabilities we need to expand our app’s features in the future,” a spokesperson said.
WhatsApp will stop working on iPhone 3GS at the end of this year.
It will also cease to function any iPhone running iOS 6, so any phone which hasn’t been updated to a later operating system will lose WhatsApp.
The change also affects first, second, third or fourth generation iPads that haven’t been updated.
WhatsApp will cease to function on any Android tablet or phone running Android 2.1 or 2.2.
This affects any phone released between 2010 and 2011 which hasn’t been updated.
Windows phone users
Anyone still using Windows Phone 7 will not be able to use WhatsApp anymore.
Blackberry and Nokia users
People who have these phones are safe until June 2017: BlackBerry OS, BlackBerry 10, Nokia S40 and Nokia Symbian S60.