What a great kickstart to our week! Nintendo has announced the new Nintendo Switch OLED. Previous rumours had suggested this new Switch would ship with a brand new Nvidia chip, however, this new OLED model is mostly a screen upgrade.
Nintendo lists this Switch OLED model as supporting 1080p via TV mode. However, there are rumours suggesting that it will include 4K support, thanks to the Nvidia chip upgrade.
From a more technical standpoint, there is an in-built storage bump to 64GB (up from 32GB), a new dock with a wired ethernet port, and improved audio. Nintendo only mentions 1080p for the TV dock, so it is not clear yet if the rumoured 4K mode is apart of this OLED Switch update.

Otherwise, theres nothing else new. All currently games, original Joy-Cons, and other accessories will function as normal with Switch OLED. The new dock will also work with both the existing Nintendo Switch and the new OLED model.
Nintendo is offering the new Switch OLED model in black and white, on sale October 8th for $350.