Google has updated its Drive app on iOS to introduce some iOS 9 features to it. Version 4.4 of the app adds 3D Touch support to the iPhone 6s and 6s Plus. When you press on the Drive app more you will get two options: upload a photo or search through your Drive files. You can now also receive push notifications when a new file is shared with you. Searching for files through Spotlight in iOS is also possible. While not mentioned in the changelog, it seems this version adds Split View and Slide Over feature for the iPad and iPad Pro..
Source: 9to5Mac | Download: Apple App Store (Free)