Testing iPhone apps in iOS 3.0

Officially Apple let developers deploy apps that's compatible with iOS 3.0 to iOS 4.2. However there are some APIs and some hardware features that's not present in some devices 开发者_开发技巧or in some iOS versions.

However if you only have one testing device, and you want to try to install a clean iOS 3.0 to that, for testing purposes, what is the official way to do it? I tried looking all over Apple developer website and it does not give me anything.

I asked a similar question before: A TimeMachine taking my iDevice back to 3.1.2?

After that I did a thorough research on this topic. It finally turned out, that actually there is no official way for a developer to downgrade her or his own device back to an earlier iOS. Apple just doesn't allow that to happen.

However, in your code, there are many things you can do to make sure your app is supported in an old version iOS. Check this great post: http://cocoawithlove.com/2010/07/tips-tricks-for-conditional-ios3-ios32.html

If testing on the iOS Simulator is enough, you can achieve that by installing previous versions of the SDK which contains the older versions of iOS.

As for device, there is no quick way to switch between iOS versions on a single device.

I struggled with this for a while, and eventually gave up on downgrading and bought a used 1st gen iPod Touch, which can't be upgraded to 4.x so it's guaranteed to be 2.x or 3.x (2.x is easily upgraded to 3.x).

Now I test on that. Added benefit is that when testing on it you're at the same time checking the performance on a slower (slowest?) iOS device too.