This is not a brand-new or upgraded console. It is simply the new standard base model for the PlayStation 4 moving forward.
Though it has a new physical design, this new PS4 is simply the standard base model moving forward. You will likely still be able to purchase the original PlayStation 4, but Sony seems to be in the process of phasing it out in favor of this new model.
It's much smaller than the original PlayStation 4.
As you can see in the picture above, the new standard PS4 is much smaller than the original model released in 2013. According to Sony, it's 30% smaller, weighs 25% less, and consumes 34% less power compared to the original PS4 model.
Though it does not support 4K gaming, it will support HDR gaming for those that have HDR-compatible televisions.
Unlike the PlayStation 4 Pro, which supports 4K gaming, the slim PlayStation 4 will only support HDR gaming for those that have HDR-capable televisions.
In the near future, Sony will release a firmware update for all PlayStation 4 models (including older models) that will make them HDR-compatible.
If you're not familiar with the term HDR, it's a feature on certain high-end televisions that stands for "high-dynamic range imaging." Essentially, it means that the range of colors the television can display is far greater than that of a normal television.