Hangouts can now be initiated via profile pages, and old Messenger conversations can be accessed using Google's Takeout service. Google Apps domain support is also bundled into the update.
Google+ for iOS can be downloaded from the App Store for free. [Direct Link]- View, edit, and share photos stored in Google Drive
- Google Apps domain support: restrict posts to the domain, domain icons to identify members
- Hangouts app replaces Messenger for messaging and video calls. Visit Google Takeout to download your Messenger data
Article Link: Google+ for iOS Update Replaces Messenger with Hangouts, Adds Google Drive Support