A new update will see millions of users unable to use the messaging service
Millions of iPhone and Android phones which have outdated operating systems will not be supported on the app.
Smartphones using Android 2.3.7 and iPhones with iOS 8 or older will be affected by the update.
In a statement, a spokesperson for WhatsApp said: "This was a tough decision for us to make, but the right one in order to give people better ways to keep in touch with friends, family, and loved ones using WhatsApp."
Irish Independent Technology Editor, Adrian Weckler, explained the decision was made due to security reasons.