Massively has pointed out a few highlights of what the Apocrypha 1.2 patch brings to EVE Online, but today's dev blog from CCP Greyscale explains the big changes they've made to the overview. The overview is an essential aspect of the UI which allows players to better understand what's happening around them in three dimensional space, so any major change to how it works or displays threats is something all EVE players really need to be aware of.
When the Apocrypha expansion launched in March, players (finally) gained the ability to freeze the overview by holding down 'control', a useful enhancement which hopefully has led to fewer friendly fire incidents. Today's patch, however, changes how hostiles are displayed in the overview. CCP Greyscale's tl;dr version is "After patch, blinky people on overview = war targets, not outlaws." That said, there's a lot more to this and he details how and why they've made changes to the overview in his dev blog, "Apocrypha 1.2 - Important Overview Indicator Changes". The players are discussing the changes Greyscale outlines in a forum thread connected with the dev blog, so be sure to weigh in there with your views or questions.