Why would the WS-13 be dead? If I recall, the last news I heard about it was good. Where is your source for this? WS-19 is still quite a long way out from being operational, just like the WS-15.I asked a similar question on the engine thread a while back. Someone answered that the WS-13 is dead, because China is focusing on the WS-19 now. Which does make sense.
Interestingly, I heard a few weeks ago from a close source in the PAF that the Block III would be getting an engine upgrade... I thought he was mistaken (because the WS-13E is dead)... Apparently he wasn't mistaken, and the upgrade was this RD-93MA.... (BTW, he also told me some more good news, but I'm not gonna share it because it's just on the PAF's wish-list right now and it may not happen.)