The document "ViewController.xib" could not be opened. Could not read archive.
Please use a newer version of Xcode. Consider changing the document's Development Target to preserve compatibility.
Xcode 升到5.0后。再回去用4.6打开的时候 .xib文件就会提示这个错误
解决办法：用5.0打开project. 选择.xib文件。然后在右边的列表里找到Interface Builder Document ->Opens in 这里选择Xcode 4.6 然后关闭工程。重新用4.6打开。
一切正常！
Open the Storyboard file on Xcode 5, And then: 1. Open file inspector 2. On "Interface Builder Documents" section change "Open with" to Xcode 4.6 (if it's 5.x). 3. Save, Close the project and open that with old Xcode.
It should work now.