Google has updated the official Google+ app for iPhone to version 184.108.40.20678.
The refreshed app brings features that are already available in the Android app, as well as on the Google+ mobile website, including: Instant Upload, What’s Hot stream, and the ability to see who +1d a post
The app is (of course) free, and works on devices with iOS 4.0 or later. You can download it here via App Store.
The Google+ app was first released for iPhone in July 2011, and is currently available in more than 40 languages.