We already know that iOS 9.1 includes several new features like fresh emoji and an improved version of Live Photos, but it turns out that the update brings another notable feature for Sprint users.
Sprint says that with iOS 9.1, its iPhone-toting customers can use Apple’s enhanced Wi-Fi calling feature to make and receive calls from your iPad, iPod touch, Apple Watch, or Mac using the phone number that’s attached to your iPhone. That means that if someone calls your iPhone, you can still answer if your iPhone is out of reach but you’ve got another Apple device nearby.
To enable this single-number calling feature, you must first install iOS 9.1 on an iPhone 6s, iPhone 6s Plus, iPhone 6, iPhone 6 Plus, iPhone 5s, or iPhone 5c. You must then ensure that your iPhone and other Apple devices are using the same Apple ID and are signed in to iCloud. You then enable Wi-Fi Calling on your iPhone (Settings > Phone > Wi-Fi Calling) and, finally, you’ll need to enable your secondary devices to receive your calls by going into Settings > FaceTime > Calls from iPhone.
The process to enable this new feature may take you a few minutes, but it’s probably worth the effort for you Sprint folk to go through the effort. Not only does this Wi-Fi calling work when you’ve got limited cellular service, but making calls over Wi-Fi won’t count against your minute or data limits. So yeah, if you’re an iPhone user on Sprint, you should definitely follow the steps above.