I’ve seen in the past applications that popup a warning when they come out with an update.
Obviously I can put something on my server with the latest app version number but that would require me to remember to change that file. Does apple have some kind of json feed or something where I can pull down my latest app version?
It would also be great if I could get the latest ios version too.
Apple doesn’t provide this, unfortunately. As you said, you have to put something on your server for your app to poll or deliver a push notification to the user when a new release comes out.