Facebook-owned WhatsApp, which is used by a billion people worldwide is to end support for a number of operating systems including Android 2.1 and Android 2.2
Blackberry OS 7 and earlier
Blackberry 10
Nokia S40
Nokia Symbian S60
Windows Phone 7.1

Source : http://info247.news/whatsapp-to-end-blackberry-support/

The company said it wanted to focus development “on the mobile platforms the vast majority of people use”.

The firm said in January 2016.

We are also planning version 10.3.4 for later this year with even more security improvements,”
Source : http://info247.news/whatsapp-to-end-blackberry-support/

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.