https://wccftech.com/download-apple-releases-beta-4-of-ios-14-5-tvos-14-5-macos-big-sur-11-3-and-watchos-7-4-to-developers/

Apple has seen fit to release beta 4 of its upcoming iOS 14.5, tvOS 14.5, macOS Big Sur, 11.3, and watchOS 7.4 to developers for testing purposes. The new beta builds arrive two weeks after the previous build. If you're a developer, you can download the latest build on your compatible device right now for free. As for now, let's see what the new beta builds have to offer.

Apple has seeded iOS 14.5, iPadOS 14.5, macOS Big Sur 11.3, watchOS 7.4, and tvOS 14.5 beta 4 to developers with updated features and improvements. The updates also include bug fixes and performance enhancements along with security updates. This contributes to the overall stability of the platforms.