I'm having difficulty finding what versions of Android and iOS are supported by Calabash. I have gone through the GitHub documentation and Xamarin help files, though they only specify what supporting software versions are required (OSX, Ruby, and XCode for iOS).
Searching through StackOverflow and the Calabash Google Group, I've only been able to find that some people are using it for iOS 8.3 testing (I haven't been able to locate any solid numbers for Android). I was hoping to be able to find more concrete numbers.
Calabash Android and iOS support the most recent versions of Android and iOS.
Calabash iOS supports Xcode 5.1.1 and Xcode 6 back to iOS 6.
On the iOS side, we've had (almost) zero day support for iOS releases. There are, however, many issues that only Apple can resolve; which they usually do in the months following GM release.
We try hard to provide beta support as they are released. The exception is with major releases, which are incredibly disruptive.
The iOS README.md has up-to-date information.
On the Android side, I am not aware of any version limitations.