Ok, what about runtime support for older devices/iOS versions? They didn't say anything about it.
They said that they were accepting apps built with Swift for iOS 8 and OSX 10.10 so sounds like it won't work with older OS version. They weren't all that specific about it though so I could be wrong.
Re: The Swift Programming Language
#81New language runs on Obj-C runtime. Maybe apps written in Swift can run smoothly on existing OS.