Today WhatsApp has been added to the list of supported apps on CarPlay, more notable is that it is the first third-party app on CarPlay which supports messaging. Other apps, mainly music ones are offered such as Spotify and Google Play Music.
But today WhatsApp was updated to add in support for CarPlay, which allows the driver to read unread messages, ask Siri to read those messages as well as use Siri to send messages, just like Siri can do on iOS currently.
Other apps on CarPlay
The update for WhatsApp on iOS is out now.