WhatsApp is to end support for a number of operating systems including Blackberry 10, Nokia Symbian S60 and Windows Phone 7.1.
The company said it wanted to focus development “on the mobile platforms the vast majority of people use”.
Facebook-owned WhatsApp, which is used by a billion people worldwide, will stop working on the named operating systems by December 2016.
But it will still work on Blackberry’s latest smartphone which runs Android.
Most of the operating systems that WhatsApp is dropping support for are legacy operating systems, which are no longer updated or installed on new devices.
The exception is Blackberry 10, which was launched in January 2013 and is still being developed by Blackberry.
“We are also planning version 10.3.4 for later this year with even more security improvements,” the firm said in January 2016.
However, the operating system has failed to gain traction with smartphone users and now accounts for less than 1% of the market.
There had been speculation that the handset-maker would wind down support for Blackberry 10 after it released a smartphone running Android, and closed its “Built for Blackberry” programme for app developers.
But the firm has insisted: “We’re not abandoning the loyal customers who have contributed to our success.”
The full list of operating systems WhatsApp will stop supporting is:
Android 2.1 and Android 2.2
Blackberry OS 7 and earlier
Nokia Symbian S60
Windows Phone 7.1
“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,” WhatsApp said in a blogpost.
“When we started WhatsApp in 2009… about 70 percent of smartphones sold at the time had operating systems offered by BlackBerry and Nokia.”
The firm said mobile operating systems offered by Google, Apple and Microsoft accounted for 99.5% of sales today.