Earlier on Dec 26, the 23rd 052DG and 6th 055 were launched at Dalian, moved out of dock on Dec 27:
There's one more 052DG, the 25th, yet to be launched in Dalian. Words are that further batch of four 052DG + four 055 were ordered. This would bring the total number of 052D/G to 29, and 055 to 12. In addition to the existing six 052C, PLAN would have 47 area air defense ship by early 2020.
One more thing, the 052C 150 seem to be under refit beside 137 as well. 137 is undergoing a major refit similar to what's done on 136. I wonder what kinda of refit 150 would undergo.