title: Availability.h file not found - Xcode 4.6.1 - Objective-C
body: <p>After I updated XCode to 4.6.1 version, when I open a project developed in the last Xcode version, it gives me an error when I run the application, on the <code>#import &lt;Availability.h&gt;</code> (I don't know in which class is that code line). The error I get is: "'Availability.h' file not found". How can I solve this?</p>