How to make my iphone application compatible with iphone 4.0 OS

Can any one help me out.

I want to make my iphone application developed in 3.1.3 SDK compatible with iphone OS 4.0

It is a simple application of getting data from a remote web serv开发者_StackOverflowices and showing the data in a UItableView

To get fast app switching, you simply need to compile against the new iOS 4 SDK.

APIs and other things provided by the OS (such as UITableViews, text labels, etc.) will automatically be higher resolution variants, even without being recompiled.

Other things such as bitmap artwork, icons, splash screens, etc. you need to update yourself. Apple gives some pointers here and here.

Unfortunately, you can't fetch data in the background periodically with the current multitasking APIs, if you were interested in doing so.