Or at least, the actress isn't. Only Sarah Wayne-Callies and IronE Singleton got last day goodbye dinners during the wrap for the filming. And the character has not been mentioned as being dead in any of the affiliated programming (such as Talking Dead).

Carol still could show up as a zombie at some point, much like her daughter... but the actress has not been in her last episode yet. I'm rather hoping she's still among the un-undead.