Apple is launching the betas of its operating systems in a group more and more frequently, but always there are some exceptions.
Today the fourth beta version of macOS Sierra 10.12.6 has been released, which is not accompanied by a beta version of more operating systems.
Version 10.12.6 may be the last officially released Sierra macOS, since in Apple are already engaged in the active development of macOS 10.13 High Sierra. So do not expect too much news in it, simply fixes on stability and security.
The best tomorrow?
What the developers expect otherwise and not these betas of macOS Sierra: the second betas of macOS High Sierra, iOS 11, watchOS 4 and tvOS 11.
There were chances that they would be launched today, but everything indicates that it is going to be Tuesday morning around seven in the afternoon in Spain (noon in Mexico).
As always, we remind you that these beta versions are unstable and therefore are not recommended for general users who expect the best performance on their day to day machines.
If you are a developer and want this beta to work on your applications, you can upgrade through the Mac App Store provided you are registered in the Apple Developer Program.