WhatsApp earlier this year announced they would no longer be supporting BlackBerry OS and BlackBerry 10 handsets by the end of 2016 but it seems they have changed their mind.
According to an update in the FAQ section of the WhatsApp website, it has now been extended to June 2017. Read below:-
WhatsApp support for mobile devices
As announced in our blog, we will soon be ending support for certain devices. On June 30, 2017, we will no longer support the following platforms:
• BlackBerry OS and BlackBerry 10
• Nokia S40
• Nokia Symbian S60
The following platforms will no longer be supported at the beginning of 2017:
• Android 2.1 and Android 2.2
• Windows Phone 7
• iPhone 3GS/iOS 6
These platforms don't offer the kind of capabilities we need to expand our app's features in the future. If you use one of these affected mobile devices, we recommend upgrading to a newer Android running OS 2.3+, a Windows Phone 8+, or an iPhone running iOS 7+ before the end of 2016 to continue using WhatsApp.
Once you have one of these devices, simply install WhatsApp and verify your phone number on the new device to continue using WhatsApp. Keep in mind that WhatsApp can only be activated with one phone number on one device at a time.