Alongside iOS 11 beta 4, Apple has also released the fourth Betas of macOS High Sierra , watchOS 4 and tvOS 10, all of which are now available for download through the developer center. The updates have been released for all supported models of these operating systems.
The fourth beta of macOS High Sierra for Macs, which brings features like a new Apple File System, upgrades for certain stock apps, HEVC video play and more focuses on bug fixes and improvements. It is unlikely that any new features have been introduced in developer beta 4 release. It you are running a previous beta then you can update through the Updates section of the Mac App Store.
Same is true for watchOS 4 and tvOS 10. Both of these are also minor releases that are meant to fix bugs faced by developers in previous betas. If any notable changes are discovered in developer beta 4 for any of these operating systems, then we will be sure to update this post.