This, as far as I know AEP500 is fully ready but they are not using it. There were alot of claims previously about KJ-600 with AEP400/500 before as well.
I think we've heard that before.
For engines, the proof should be in the pudding.
My standard is two years of sustained production with a "new powerplant" should be the baseline requirement for us to be able to retrospectively identify a powerplant as having been "ready".