Update KB4033637 (Updates to Windows 10, Version 1607 for update applicability: August 30, 2017) will distributed via Windows Update and adresses the following issues:
This update includes diagnostic and functional improvements for determining the applicability of updates in Windows 10 Version 1607. The files and resources in this update ensure that feature updates are installed seamlessly to improve the reliability and security of Windows 10.
Not too many details, so I suggest my blog post Windows 10 V1607: Mysterious Update KB4033637 that has more insights.
Overall: It’s good, that Microsoft finally released a few words about that update – but it’s ‘too late and too less’, imho.