Users of the WhatsApp messaging service could find themselves unable to use the app as the technology stops running on older mobile phones.
The popular app will no longer work on older phones from midnight, as the company "looks ahead" to the future.
The company said its new security features will be unable to run on out-dated models, and advise users upgrade to a newer Android, iPhone, or Windows Phone.
A statement from WhatsApp read: "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."
The mobile phones affected by the withdrawal, from January 1, 2017, include:
- BlackBerry OS and BlackBerry 10
- Nokia S40
- Nokia Symbian S60
- Android 2.1 and Android 2.2
- Windows Phone 7
- iPhone 3GS/iOS 6
WhatsApp said they will extend support for BlackBerry OS, BlackBerry 10, Nokia S40 and Nokia Symbian S60 mobile phones until June 30, 2017.
"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.
"If you use one of these affected mobile devices, we recommend upgrading to a newer Android, iPhone, or Windows Phone before the end of 2016 to continue using WhatsApp."