I can imagine there will be an upgraded WS-10 version in time, but I'm not sure if existing fighters will be necessarily re engined; do USAF F-16 and F-15s get re engined with new versions of their engines?
And the IOC date stated would be a fighter with the "4S" in that famous CCTV interview. I wonder if J-20 can supercruise and manouver competitively with uprated WS-10s, if the engine exists. Personally I'm still of the belief that the engine equipped aboard the next prototype will be WS-15, until something else comes along to direct otherwise.
Hmm the last update was a while ago though.