I've also used my iPhone 5 since July with no issues. I use it with the follow me feature.
I also use an iPad
mini 2 when follow me is not needed.
Let's make this easy so we don't add confusion with so many new pilots coming soon.
Any Apple device with a processor older than A7 (iphone 5 and older / iPad 4 and older) was
not compatible with the app and could not even download to those devices unless they were jail broken. If anyone tried, they would usually get a "device not compatible" error. [Note that iPad 4 is
not the same as iPad Mini 4]
Here is the list of compatible devices from DJI which shows that 5s and later is all that was compatible. Note that IP5 and earlier is
not listed.
Once GO 2.4.0 was released on October 23, suddenly devices older than the A7 processor generation
were able to download the app without getting the "device not compatible" error. I actually noted as much
in a thread at the time just to let people know.
Like I said before, even though GO can now be downloaded to older devices, IMHO it wont give the best experience. That doesn't mean it
wont work, just not well in comparison to more capable devices.