Build an iOS4 app that will also deploy on iPhone OS 3.x devices

Question

I've got a couple of applications in the App Store at the moment which I've had ready after the release of iOS4. If I try and download one of these in the App store on a 3.x device, it will tell me I need to upgrade. Is there a way to make my application not do this, as I don't think I am using any API calls specific to iOS4.

I originally thought that this could not be done but I just now installed 'Plants vs Zombies' and 'Angry Birds' on my iPod Touch (running 3.1.3) so it must be possible as I'm sure these have released updates recently, and being in the top5 games, I would have thought they were developed using the iOS4 SDK. I am hoping it is just one value somewhere but if anyone could let me know how to do it that would be awesome :).

Answer 1

Easy. Open up your project info. Find this line "iPhone OS Deployment Target" select 3.0

You can still develop with the latest xcode and current 4.0 SDK, but if you dont make any 4.0 calls this should allow you to weak link to 3.0+ and allow apps to work.

You really should test this on a 3.0+ device to see if it works though. You can still set your Base SDK to 3.2 or 4.0.