We've been hearing rumours about From Software remastering Dark Souls and Nintendo having a Nintendo Direct today for quite some time, and both proved to be accurate.
Developer From Software and publisher Bandai Namco has announced that Dark Souls: Remastered will make its way to PC, PlayStation 4, Xbox One and Nintendo Switch on May 25 (the digital versions on May 25). These new versions include the Artorias of the Abyss expansion, better lighting, improved frame-rate, a bunch of other graphical enhancements, and the option to play together with or against five other players online, so the Japanese studio has definitely put some extra work into this.
With regards to the Switch version it will feature 1080p in TV mode and it will run at 30fps. The PC, PS4 Pro, and Xbox One X versions will offer 4K resolution and 60fps.