With the addition of 3D Touch, Facebook users on iPhone 6s and iPhone 6s Plus will be offered three quick actions on pressing the app icon. It offers to a create new post, upload photos/ videos, or take photo/video options. Unfortunately, the app listing on the App Store doesn't highlight the new 3D Touch feature addition and instead notes, "Every update of our Facebook app includes improvements for speed and reliability. As other new features become available, we'll highlight those for you in the app."
To recall, Apple's 3D Touch pressure-sensitive touch technology present on the new iPhone 6s and iPhone 6s Plus allows the new iPhone models to differentiate between a quick tap and a long press and triggers actions consequently.
Notably, Facebook-owned Instagram also started pushing 3D Touch input feature to its iOS app recently which offered Quick Actions for posting images. The version 7.8 brings support for iOS 9, iPhone 6s, and iPhone 6s Plus smartphones.
Facebook had also rolled out an app update for its standalone Messenger app adding support for watchOS 2 and multitasking on iPad. The release note on App Store read, "You can now use Messenger on watchOS 2! Send and receive voice clips, Likes, stickers, and more. With iOS 9, you can now find Messenger contacts and conversations from your phone's search screen, and access Messenger from the list of multi-tasking apps on your iPad."