The versions were released yesterday macOS Mojave beta 6, watchOS 5, and tvOS 12 for developers. In these new beta versions we find the typical improvements in their general operation, the improvement in stability and security, and in the case of macOS Mojave beta 6 some improvements in the Data Migration Assistant from Windows to Mac.
All beta versions are already in the hands of the developers and obviously iOS 6 beta 12 was also released, a version that is eagerly awaited even though it adds few changes in terms of interface or OS functions.
All Apple beta versions arrive a week after they are released beta 5 last week and therefore it seems that the pace of beta version releases is accelerating to arrive in time for the official launch that could be prepared for the beginning of September. Some media stated that September 12 would be the chosen month, but it seems that this could be sped up a bit more and have the final versions of the different operating systems sooner.
In any case, as we always say in the release of beta versions for developers, the best is stay out of these to avoid problems, failures or incompatibility with some of the tools we use in our day to day. We are about to receive the public beta versions of iOS, macOS Mojave, tvOS and watchOS, so if you want to install any of them at your own risk, they may be available in a few hours.