OpenWapp is another WhatsApp Client for the Firefox OS. However, it is still new and not as good as ConnectA2, but for those who are not able to use ConnectA2, OpenWapp is a nice alternative. It can also verify and activate your WhatsApp account and you can chat with your friends on WhatsApp. Other supported features include sending emojis, pictures, videos and audio messages. Status can also be changed easily from the settings.
Marketplace URL : https://marketplace.firefox.com/app/openwapp