Testing for multiple iOS versions on one device

Apple really doesn't support installing of older OSes on iOS hardware. In the past the feature was there to allow back-installing but apparently Apple didn't consider that to imply official "support" of this feature.

It's possible that there are ways to hack this but I'm not sure.

Anyway, what's expected by Apple is that you have separate devices for each older OS that you want to support.

Regarding the Sim, 4.2.1 is a dot release and I don't think there is or will be a Sim that targets that version. 4.2 is supported and nominally is the same as 4.2.1. I see 3.2, 4.0, 4.1 and 4.2. 4.3 might be available with a beta Xcode.

You should be able to predict from the cause of the crash on launch whether it would be fixed for 4.2.1.

Also, when you build your app targetting 4.2 it will still debug on a 4.2.1 device, or on any device between the deployment target OS and the base OS.

 

No, there is - you need a physical device for each different OS version you want to test. Don't rely on the simulator. Buy some iPod touches for testing; they are legitimate business expenses (tax deductible).

 

Different devices with the same OS can be configured differently. A crash log is always a good way to start this investigation. If apple didn't send one you should check iTunes connect or try to get one from a user.

 

How do you get a crash log from iTunes Connect or from a user?

I'm having the exact same issue trying to debug for older versions, and I'm almost to the point of jailbreaking my second iPhone in order to downgrade it. It's really frustrating that I might have to do that.

 

Edit: Nevermind, found it. There's no reports there though. Hrm.

 

See Tech Note 2151 (it's in the Xcode documentation window) for info on how to find crash logs. If a user has reported a crash to you then they should be able to find the crash log on their computer and email it to you.

@cnstoll, there is reportedly a hack where you modify something in the etc/hosts file on your Mac that allows you to back install older OSes on your devices. I tried this out a few months ago but didn't succeed but others have claimed success. Google for that before you need to jb.

 

Thanks for that tip, I might try that. I finally solved the old OS bug that a user reported, and the way I did it was getting a friend with an old phone to replicate the problem and send me a crash report.

The way we got the crash report was through the iPhone Configuration Utility. If anyone reads this but hasn't used it...I highly recommend it. I found it a while ago but I hadn't really used it yet, but it really saved the day here. Great way to manage Ad Hoc installs and view the device's console.

If I can't manage to downgrade my old phone using that /etc/hosts method, which I haven't tried yet, I'll probably just buy an old iPod Touch or iPhone 3G off craigslist for testing purposes. It's frustrating but I'd rather have the peace of mind of being able to test on older versions myself without relying on other people to help.