When upgrading Xcode, it wil overwrite the old one including the iOS simulators. To install an old version of Xcode: Download the .dmg from the Apple devcenter. Open this package so you see the Xcode.app. Create a directory for this Xcode version, e.g. /Applications/Xcode6.4 or some other name. Put the Xcode.app into this new directory. […]