iPhone 6s and 6s Plus devices.
As you're probably aware, 3D Touch allows you to quickly access a handful of vital app shortcuts or other crucial UI elements by exerting force onto the display.
Well, apart from the majority of stock iOS apps, a large amount of third-party ones have already scored support for the agile feature (actually, here is a list of the 10 more popular ones).
The latest addition to this list is one of the more popular messaging services around - WhatsApp.
The messenger app now allows you to hard-press its icon and access two of its most often used features - Search for a contact and start a new chat.
We did not notice any other additions to the app's interface. There doesn't seem to be a quick reply feature of sorts added to the heads-up notifications, either.
In related news, all users of jailbroken iOS 9 devices can now employ a somewhat similar functionality on their devices thanks to a Cydia mod, logically dubbed "Forcy". You can read more about it here.