What did the Windows 10 update for the first time?

Windows 10 will be officially released at the end of the month, but for this new system, this is just another new beginning, followed by Microsoft will continue to provide updates to create a new Windows as a service, than the original Windows 8.1 Update 1 The update is more powerful.

Windows 10's development code is Threshold, so the first wave of updates is called "Threshold wave 2", which is tentatively scheduled to be released in October, which is only 3 months after the official version is completed.
According to sources familiar with the Microsoft program, this update has no obvious new features (time is too late), its main purpose is deep optimization and stability enhancement.
Moreover, the system version is still Windows 10, so it will not become Windows 10.1.
Windows 10 has undergone unprecedented public testing, but there are thousands of devices in the world. Such a huge system will always have various problems, so after the release, Microsoft will surely receive a large number of manufacturers and users. Feedback, which is valuable and urgently needed to be improved, will be considered within Threshold Wave 2.
I don't know if the SD card installation application, Skype application will appear with it?
As for Redstone, it may be a subsequent larger upgrade, and the change will be more. At that time, it became Windows 10.1?