Both the public and developer betas of iOS 14.5 and iPad OS 14.5 are now available to those enrolled in the respective programs. The dev one was released Tuesday and MacRumors reported that the beta version followed Wednesday.
Latest iOS 14.5 and iPadOS 14.5 Betas Now Available
The most high-profile feature coming with iOS 14.5 (and watchOS 7.4) is the ability to unlock with your Apple Watch whilst wearing a mask. For users on the relevant beta programs, the latest updates can be accessed via Settings > Software Update.