Seems like this was the week to discuss optionals and outlet properties in Swift. Scott Berrevoets kicks us off with an analysis of the default outlet property as used by Apple and then recommends some changes. Curtis Herbert has similar views in his piece on the same subject. Finally, David Keegan has a great article not specifically about outlets, but about optionals in general.
Basem Emara with a long and comprehensive article on creating frameworks which target iOS, watchOS and tvOS. The end result is a single framework project for all the platforms, with test targets, and distribution via CocoaPods or Carthage. This really should be easier though!
As you'd expect from any post by Peter Steinberger, this quickly gets into the weeds of a tricky debugging problem. However the lesson which comes out of it is simple. Prefix your category methods, even in Swift.