I\'ve upgraded to XCode 4 which comes with the 4.3 version of the SDK.
But we\'d like to make sure our app runs on devices that have 4.2 and later, not just 4.3.
You should always set base sdk as the latest version, then the lowest supported version is determined by "deployment target" setting.
As long as deployment target is set to at/below 4.2, it should be fine..