I hope you weren't interested in playing the newest Battlefield 4 DLC, Naval Strike on the PC because you're going to have to wait a bit. The DLC has been delayed without word on when it will be released.
Naval Strike introduces four new maps and an emphasis on sea battles. Premium members were suppose to get access to it today. Unless you are playing on the console though, you won't be trying out the new maps, weapons, or vehicles that come with the DLC.
No word on what is causing the delay other than it's an issue they found with the DLC. I'm going to guess that this bug is bigger than the normal ones they let through and try to patch up later on. Because we know, anytime DICE releases an update or a DLC, the inevitable number of bugs comes along with it.