I know that iOS doesn't want you to use http connections, and for https, you can't use self-signed certificates anymore. The cheapest certificate with a real authority chain available uses domain verification (DV).
Is that good enough for iOS connections, or do you need an OV or EV certificate?
(The background of this is that I understand many people consider DV certs to be insecure. My particular need, which is behind a firewall, doesn't need the security provided by OV or EV certs, but I'd better buy the more expensive one if iOS is going to refuse to connect with my site with a DV cert. I know I can make an exception for my app, but this is for a site for installing an app over-the-air under the Enterprise dev license, and I don't think there's a way to force an exception for installation. At least, I think that is my problem -- I get a "can't find website" error downloading the manifest file.)