Aditya Krishnadevan with a fantastic article on excluding actions defined inside your app from showing up while using that app. The implementation is a little fragile/strange but I'm glad this feature exists, I had no idea it was even possible.
Big changes if you're using AsyncDisplayKit, and from the stats in this post it appears that many people are as it's apparently in use by over 10,000 apps! Even if only a fraction of those are shipping, that's really impressive. There's some breaking changes of course, but there's also a migration guide to assist you.
Matt Gallagher with his recently released library CwlSignal for reactive programming. It's also worth reading the accompanying introductory post which goes along with it. I especially enjoyed the section on the history.
Ole Begemann on the new warning in new Swift builds when interpolating optionals into a string. He goes through the options for working around the warning and then comes up with a much simpler version by defining a new version of the nil-coalescing operator.