Problem installing ad hoc-provisioned app built with SDK 3.1.2 on device running iPhone OS 3.0

I'm trying to install an ad hoc-provisioned iPhone app compiled under the 3.1.2 SDK on a device running iPhone OS 3.0 via iTunes. I'm getting a message "The application was not installed b开发者_StackOverflowecause it requires a newer version of iPhone OS." The build settings for the project are "iPhone Device 3.0 (Base SDK)" and "Distribution." The app successfully installs on devices running 3.1.2.

Is it possible to build for OS 3.0+ with the 3.1.2 SDK (rather than just 3.1.2)?

There are two settings you must pay attention to:

• Base SDK: "The product will be built against the headers and libraries of this version of the SDK."
• iPhone OS Deployment Target: "Code will load on this and later versions of iPhone OS."

Any chance your Deployment Target is set to iPhone OS 3.1?

Build > Clean All Targets, then building again solved the problem. Thanks to Ole, who indirectly reminded me that I should do this.