You can download the update directly on your iPhone, iPad or iPod Touch through the Apple App Store or by using the link which follows:
Google+ version 4.3 for iOS has the following new features and improvements:
- New photo editing features: add filters, rotate, and crop
- New profile design
- New notifications tray
- New set-up flow for new users
- Control the volume of posts that you see in your stream from individual circles/communities
- Filter search results by best or most recent
- Tell your friends about a community (by sharing it or sending an invitation)
- Re-share posts to communities
- Display counts for unread messages in your communities
- Additional community moderation features
You can download Google+ for Android for your Android smartphone or tablet here. You can also learn more about the update by following the source link below.
source – Google