WhatsApp yesterday released desktop apps for Windows PC and OS X. As mentioned in the blog post, the web app is just an extension of the app on your smartphone. It works similarly as WhatsApp for Web which means the app mirrors conversations and messages from your mobile device.
The desktop app has been natively for the respective platforms similar to Franz probably using the Electron framework. Electron is an upcoming platform allowing to build cross-platform desktop apps using HTML, CSS and JS. We have been noticing the same characteristics on WhatsApp desktop app as on Franz. Since it is a native app this time, so it will have native desktop notifications along with few keyboard shortcuts.
Basically, if you are using Franz you have nothing new to look for, except keyboard shortcuts (which we too have to find out). But it’s good to know WhatsApp initiating this for its big consumer base. Download the app from http://www.whatsapp.com/download
Source : WhatsApp Blog