I have installed latest Xcode 7 beta 2 version, when I am trying to run the application in iOS 7.1 Simulator its giving this error message:
The iOS 7.
In Xcode 7 beta 6 this seems to be possible now.
http://adcdownload.apple.com/Developer_Tools/Xcode_7_beta_6/Xcode_7_beta_6_Release_Notes.pdf
Xcode 7.0 beta now supports downloadable legacy simulators. (20699475)
I haven't found a place to download these yet though. I will update when/if I find them.