You'll get a nasty malware-filled surprise if you do...
All you have to do is click on the link and you'll end up with the all-new version of WhatsApp.
Except you won't, you'll end up with an enormous wave of malware and potentially even ransomware that could then use software to take your phone hostage.
"WhatsApp Plus is an application that was not developed by WhatsApp, nor is it authorized by WhatsApp. The developers of WhatsApp Plus have no relationship to WhatsApp, and we do not support WhatsApp Plus."
"Please be aware that WhatsApp Plus contains source code which WhatsApp cannot guarantee as safe and that your private information is potentially being passed to 3rd parties without your knowledge or authorization."