I just updated to iOS 7.0.4 on an iPhone 4S and the app is working fine… The same that it always did with iOS 6. I waited a while before updating to iOS 7 due to some issues others appeared to be experiencing with eKEY but everything seems to be working fine now. I updated the eKey app to its most recent version first and then updated my phone to iOS 7.
Ryan Bassett about Supra eKEY