I want to test my app on both iOS 7.0 and iOS 8.0. I upgraded my iPhone5 to iOS 8.1. Now the only way to test my app in these OS' are using Simulator. But after upgrading my Xcode to 6.1. I'm unable to see iOS 7.0 and 8.0 Simulators. I need to install these simulators in Xcode 6.1. Is there any way to install these Simulators in Xcode 6.1?
NOTE:
1) I copy pasted these simulator SDKs from old Xcode to the Xcode 6.1's contents but it didn't work.
2) I tried installing these from Xcode > Preferences > Downloads but these doesn't show up in the list.
3) I removed all the Devices from Xcode's Window > Devices and then restarted the Xcode and re-added them but these simulators doesn't show up.
Only iOS 7.0 and later simulators are supported on Xcode 6.0.x and 6.1.x. Only iOS 7.1 and later simulators are supported on Xcode 6.2 and greater.
The older simulators runtimes are not compatible with the new CoreSimulator architecture. You need to install Xcode 5.1.x if you want to run iOS 6.x simulators.
The iOS 7.0 simulator does not work on OSX Yosemite, so you need to be on OS X Mavericks if you want to run the iOS 7.0 simulator.
The iOS 8.0 simulator is not available as DLC. It is only supported in Xcode 6.0. If you really want to use it with newer versions of Xcode, you can try copying the iPhoenSimulator8.0.sdk and iOS 8.0.simruntime from Xcode 6.0 into Xcode 6.1, but as stated, this is not supported.
See:
/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/Library/CoreSimulator/Profiles/Runtimes/iOS 8.0.simruntime
/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator8.0.sdk
来源：https://stackoverflow.com/questions/26491922/how-to-install-ios-7-0-and-ios-8-0-simulators-in-xcode-6-1