[swift-evolution] Moving from Swift 2 to 4

[Jonathan Hull]

Is there a reason why the migration only applies to Swift 3?  I have some older files which I haven’t gotten around to upgrading until now, and Xcode Beta says I need to migrate them with an older version of Xcode.  Right now, I still have that older version, but once Xcode gets upgraded in the fall it will no longer be possible (or is it a temporary limitation)?

Seeing as there is a Swift 3 compatibility mode, we should at least provide the ability to migrate from 2->3, seeing as it already exists, no?

Thanks,
Jon