China already has 50+ J-20 being built as of 2019. The fact that they're already have that much meant J-20, does this mean they already solved the WS-15 and the stealth coating development obstacle?
Answered by: Zhao Dashuai,knows Mandarin Chinese
As far as the engine is concerned, J-20 has been using WS-10 variants for the production batch. There are also images of J-20 with serrated stealthy engine nozzles flying since 2017.
J-20 has been featured prominently in the official CCTV7 military channel in the past 2 years. The convention is. A weapons platform won’t have such high exposure unless there is a more advanced variant already flying. So I’d expect the J-20 (possibly named J-20B) with this new engine is already flying among PLA forces for analysis.