It's taken its time to get here but O2 has announced that WiFi & 4G Calling is now ready to use on iPhone 7 handsets with the latest iOS (10.3). O2 says that the feature will be available for other handsets soon, with iPhone 6s and 6s Plus planned for inclusion in a few months' time. 

This new feature means that you'll be able to make and receive calls in poor signal areas without the need for a Boostbox or the Tugo app. 

It is also supposed to improve battery life as it’s a smoother, easier connection between 4G and 3G.

We'll be provisioning this automatically on all new connections moving forward so you just need to follow the steps in the video to enable it on your iPhone 7.