Hot on the heels of a leak that gave us an early peek at iOS 13, Apple has pushed out a beta for an update that we'll see much sooner than iOS 13.
iOS 12.4 beta 3 is now rolling out to registered developers. The update is available over the air by going into Settings > General > Software Update, or through Apple's Developer Center on the web.
There haven't been any major new features discovered in iOS 12.4 so far. The Apple Card credit card is slated to arrive this summer, though, and so the update to iOS 12.4 could be getting Apple's mobile OS ready for that launch.
Also released today is watchOS 5.3 beta 2. Like iOS 12.4, there haven't been any big new features found in watchOS 5.3 so far, which suggests that it's largely focused on squashing bugs and improving performance.