Good news for those using a 4K display. Apple is updating to OS X 10.9.3 to add Retina support for 4K displays. A beta user discovered this earlier this week. This means that Mac users with a 4K display can comfortably use the screen with their new Mac.
In the past, this was difficult, and somewhat erratic, because OS X displayed content on such screens in very, very small and very hard to read text.
Now it will offer complete support, which means it will be much easier for users to see what they are looking at onscreen.