Changed xcode deployment target to 7 but still can't run app in emulator other than iphone 6

I followed the instructions outlined here How do I acquire SDKs to build target pre-8.0 iOS?. The deployment target for my project is 7.0. My app is basically one screen with a label and some buttons on it at this point and when I try to run it in iphone 5 or 4 emulator it crashes. It always starts in iphone 6 mode even if I start the emulator first and set it to 5 or 4. I'm not sure why this is happening because previously I made another app which runs in 4/5/5s/6 etc and it still works in any emulator version fine.