ARABIAN GULF (Jan. 19, 2014) The guided-missile cruiser USS San Jacinto (CG 56) fires a close-in weapons system (CIWS) during a live-fire exercise. San Jacinto is deployed as part of the Harry S. Truman Carrier Strike Group supporting maritime security operations and theater security cooperation efforts in the U.S. 5th Fleet area of responsibility. (U.S. Navy photo by Mass Communication Specialist 3rd Class Preston Paglinawan/Released)
This is a Block 1B unit. According to this DefenseTech post from last August, all Phalanxes in the US Navy are scheduled to be upgraded to Block 1B by FY2015. The Navy is also in the process of upgrading to Block 1B Baseline 2, which adds digital radar. The Block 1B Baseline 2 refits won’t be complete until 2019.
For more info on Block 1B, see CIWS now does surface targets, too