you can say in a way its an upgraded version for the xbox one s. i think the s in this one stands for slim. it pretty much the same as the original xbox one except that its 40% smaller, and they manage to put the power supply internally instead of externally. beside smaller, its actually a tiny bit more powerful than the original xbox one s. the gpu for the xbox one s runs at 914 mHz instead of 833 mhz that the original xbox one is running. the bandwidth that the ESRAM its running at is 219 Gbytes per second or something like that compare to original xbox one which runs at 204 Gbytes per sec.
so that means, some games will either have a slightly better graphic or a bit smoother framerate than the original xbox one. beside, for those that wanted to watch 4K Blu-Ray movies, this xbox one s supports it.
games made for the much more powerful one rumored to be coming out next year will be playable on the original xbox one and xbone one s. games made for the xbox scorpio will have a much better graphic and it might run at native 4k resolution which will be downgrade for the original xbox one and xbox one s.