The "New 52" refers to a universe-wide reset back in late 2011, following the Flashpoint storyline (which itself just got an animated adaptation). I didn't read Flashpoint, so forgive me if I get the details wrong, but it involves disastrous changes to the timeline when one of Flash's enemies tries to change the past. Flash realizes something is wrong and tries to fix it, but since his memories were also being affected by the new timeline, he didn't fix it entirely properly, and that not-entirely-proper version of the timeline became the new status quo.
So now, among many other changes, Superman has a personality closer to his Golden Age self, Tim Drake was never Robin (just "Red Robin"), Barbara Gordon was and is the only Batgirl (she was paralyzed for a while, but she got better), Kid Flash is Bart Allen (and no character named "Wally West" exists), there's no superhero named "Captain Marvel" and no wizard named "Shazam" (there is, however, a superhero named "Shazam" and a wizard named "The Wizard"), and no modern-age hero has had a career longer than about five years (and there were no "superheroes" before Superman, just masked vigilantes and "mystery men" of ill repute). Furthermore, the formerly-separate WildStorm universe and the mostly-separate Vertigo universe were combined into the main DC universe (so you have things like Martian Manhunter as leader of StormWatch, or John Constantine as part of Justice League Dark).
DC still calls it the "New 52", even though it's about two years old now.