It looks like iPhone 4 runs up to iOS 7.1.2, and according to the above link, LE now requires iOS 10 or later. In theory you can use MDM to add the LE root cer

It looks like iPhone 4 runs up to iOS 7.1.2, and according to the above link, LE now requires iOS 10 or later. In theory you can use MDM to add the LE root cert to your phone's certificate store.