The new Instagram Direct service, according to the company, is designed for those moments you may want to share with a smaller, select group of people.
From the news release:
Now you'll see a new icon in the top right corner of your home feed. Tap it to see photos and videos that people have sent directly to you.
To send your own photos or videos, choose Direct instead of Followers once you’ve edited your post. When you're done editing, just choose the people you want to share with.
Today's update also includes bug fixes and performance improvements.
Instagram for iOS is free and is now at version 5.0. Instagram also announced the Android version, 5.0, available immediately at Google Play.