I'm fairly new to iOS development and I upgraded my device to iOS 9.0 beta, to see how my app faired. However, I did not upgrade to Xcode 7 beta. I'm getting an error that says my device is now "ineligible", specifically,
iPhone (3) may be running a version of iOS that is not supported by this version of Xcode.
Is this standard? Do I have to upgrade to Xcode 7 if I'm running iOS 9.0?
Yes, you need to install Xcode 7 in order to develop for iOS 9. You are able to keep Xcode 6 running alongside Xcode 7.
The problem with Xcode 7 is that it wants to change your swift code to be able to run. There is way here. Download Xcode 7 and run it. After a few minutes with some installations, connect your iOS 9 device to computer so you can see it in Xcode 7. Then quit Xcode 7 and run Xcode 6 and surprisingly, Xcode 6 will detect your device and you can run your app on it.
You can RUN App on iOS 9 device using Xcode 6, But firstly you need to build your app on XCode 7, after that it will support on XCode 6. I have checked this on My Mac.
Steps
Build the project on Xcode 7 while Xcode 6 is opened on the same project. Disconnect the device and reconnect it.(Now u can run ur app on XCode6, It may take little time to load device)
When i have checked iOS9 with Xcode6, Bugs are very less. So i have plan to support iOS9 with XCode6 for quick release. Later i will do for XCode7.
There is a way to debug devices with iOS 9 installed with Xcode 6. Go to Xcode main menu: Product -> Destination and select your device. Even though it says your device is ineligible, you can still select it and then it usually works.
If it doesn't work, try to run Xcode 7 and wait while it indexes the device with iOS 9. Sometimes you need to unplug and plug the device again.
It's easy.
- Download Xcode 7 or 7.1
- In finder Browse within both Xcode apps to following directory.
Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/DeviceSupport - Copy 9.0 and 9.1 folders over to Xcode 6 in same directory.
- Restart Xcode and reconnect your iOS 9 device.
Kaboom
As mentioned by @Ben you need to download XCode7 which release date now is right on the corner (mid-sept) but you DON'T need to build your application under XCode7. The trick is to let XCode7 copy symbols. Once done you can build your app on your device under XCode 6.4 and without to support Swift 2.0: your device will be recognized then. So yes you will need to keep a copy of XCode 6 and XCode 7 for that matter.
You need to install Xcode 7 in order to develop for iOS 9. You are able to keep Xcode 6 running alongside Xcode 7
Here's an easy workaround -- especially if you have access to Xcode 7 on a different machine (but you can do it on the same mac too):
Deploy any app, e.g. Apple sample code, from Xcode 7 once. Then go back to Xcode 6.4 and it will no longer consider the device "ineligible."
来源：https://stackoverflow.com/questions/30823478/xcode-6-with-ios-9