I have purchased a Mavic Pro and waiting for it to ship.
I of course have the option of using my exisisting smartphone (LG Stylo 4) as the screen.
I have heard that the best option is a iPhone 7 plus (may have been newest version at time of the video I saw)
That being said, I rather not spend more than I need too if I choose to buy one. Would an iPhone that will not work for phone service, still work as a screen for my drone?
Note I have ZERO knowledge of iPhones so go easy on me!

Thanks

Technically, yes, but w/o data you'll lose live maps, in the field self-authorizations, possibly some other stuff I can't remember. Some folks get away with this by using another device that acts as a hotspot and tethering their non-cellular-enabled devices via wifi.

In general, folks here do seem to complain less about later-model iPhones and iPads, but you'll also find many vociferous aOS users that have no problem running Go 4. The trick, I think, is to use one of the Android devices that have been pre-approved by DJI. Hope this helps some.

I use an iPad 4 WIFI only without any issues.

Very helpful, Thanks guys!

iPhone 7+ and iPad Mini-4 work fine for me.