Jim Hamm said that although this article mentions turning on wi-fi calling with AT&T on an iPhone 6s or 6s Plus, it will work with the iPhone 6 as well. He turned his on, and said It will be interesting to see if he ever needs this feature. He cannot see a downside by enabling this feature. http://www.imore.com/how-enable-wi-fi-calling-your-iphone-6s-or-6s-plus