I had to upgrade my phone to accept the DJI fly app. I was due an upgrade so now it works fine.
Compatible for Mavic Mini. Requires iOS 10.0 or above. Requires iOS 10.0 or above. iPhone 11 Pro Max, iPhone 11 Pro, iPhone 11, iPhone XS Max, iPhone XS, iPhone XR, iPhone X, iPhone 8 Plus, iPhone 8...