WhatsApp might stop working for many users as the company made it public that it would end support for the popular chat app on older handsets by the end of 2016.
The company said dropping support on older devices would give it the opportunity to focus more on mobile platforms used by the vast majority of the people.
The mobile platforms that would no longer enjoy WhatsApp are Android 2.1 and Android 2.2, Windows Phone 7, iPhone 3GS and iOS 6. The reason is lack of functionality to support the upcoming features.
"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 company wrote in an official blog post last February.
For the owners of the affected devices, the only way to start using WhatsApp again is by upgrading to a newer version of Android, iPhone or Windows Phone.
The Facebook-owned company earlier said it would end support to BlackBerry OS and BlackBerry 10, Nokia S40 and Nokia Symbian S60, but later it said it was extending the support for the devices until 30 June, 2017.
These changes are believed to allow WhatsApp to deeply integrate encryption and other privacy features, reports the Independent.
WhatsApp might introduce more new features. The changes rumoured to be part of updates scheduled for 2017 include a feature that would allow users to edit or delete messages after they are sent.