Apple today released the third beta of iOS 11.4, macOS 10.13.6, tvOS 11.4.1 to Developers. This update is most likely to fix any bugs and bring performance improvements.
Their is currently nothing new in all of these betas but it does include bug fixes and performance improvements. If your looking for new features coming soon to these devices, Apple a few weeks ago announced macOS Mojave, iOS 12, tvOS 12, and watchOS 5 that will release to everyone this fall.
If there are any notable changes or fixes in these updates, we will keep you updated!