I have an iphone 6s that will only go into "at&t wifi" mode when the phone is switched into airplane mode and then the wireless is turned back on. It does not matter how weak the cell signal is (often no service) it will not come on unless I actually disable the cell. Is anyone else having this issue? The only reason I really care is that I often visit an area that literally has no cell service but the wireless network is strong. Manually entering into airplane mode and back out is easy enough but annoying.