According to a blog post published a few days ago, WhatsApp will be withdrawing support for BlackBerry devices (BB10 included), Symbian 40, Symbian 60, Android 2.1 and 2.2 devices and Windows Phone 7.1 sometime this year.
WhatsApp wrote that the market right now comprises of 99% Android, iOS and Windows Phone 8 and above devices. They said that the decision was "not an easy one to make” and that the market has evolved. While other platforms will suffer, there is some respite for BB10 users as their devices are capable of running Android apps within the OS. They will, of course, lose out on Hub integration, but if they really want WhatsApp, that might be the only way.
"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.”, say WhatsApp. Finally, they add that, "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.”
Switching to another platform might be a hard pill to swallow for lovers of BlackBerry and other mobile operating systems. But they will not be left with any other option.