Introduced with Swift 2.0, #available removed the need for messy compatibility code, replacing it with a simple and consistent check. Mark Dalrymple tells you everything you need to know about it if you haven't had a chance to use it yet.
Hector Matos with eight slightly obscure features of Swift that you might not have come across yet. Covering @noescape, @autoclosure, inline lazy variables, currying, variadic parameters, dynamic, special literals and loop labels. If there isn't something in here that you didn't know then you can truly call yourself a Swift expert.
Pete Hodgson on developing feature toggles for your app. Not specific to iOS of course, but very useful for either testing a new bit of functionality, or maybe A/B testing a feature with a group of users. One thing you should consider when doing this on iOS is how to flag it/switch it on for the App Review team. The reviewer notes field in iTC is a great place to let them know about what you have enabled/disabled and potentially how they can switch it on or off.