The most popular networking library for iOS got a major update this week. It now supports tvOS and watchOS, deprecates the old NSURLConnection APIs, supports Carthage and has many other changes as well. If you were already using the NSURLSession AFNetworking APIs then the migration shouldn't be too onerous, and there's a Migration Guide which will help.
Not related directly to iOS, but usable from it! This is Google's image content analysis library available via a REST API. Offering basic object detection, inappropriate content detection and plenty more. There's plenty of apps that could be built on top of this technology.
Mike Ash with an in depth investigation of how Swift implements weak pointers. For bonus points, he also discovered a bug in Swift while researching this.