"Limited quantities" of the $399, 2TB version is available at launch.
After leaking and then confirming news of the slim, white, Xbox One redesign just over a month ago, Microsoft today announced that its Xbox One S console hardware refresh will hit retailers on August 2. A 2TB system will cost $399 and will be available in "limited quantities" in the US, Australia, New Zealand, and most of Europe on that day. Versions with 1TB and 500GB hard drives will be available for $349 and $299, respectively, at a later date.
Besides being 40 percent smaller than the original Xbox One (and sporting an internal power supply rather than that unsightly power brick), the new redesign adds support for 4K Blu-rays and streaming videos, as well as high-dynamic range (HDR) color support in certain upcoming games. The new system also comes with a slightly redesigned controller, featuring a textured rear grip and bluetooth support.

The Xbox One S shouldn't be confused with Microsoft's upcoming Scorpio update, also announced last month and promised for a holiday 2017 release. That system will be capable of true 4K gaming, as well as VR support, while being fully compatible with all existing previous Xbox One games, Microsoft says.