Is it possible that there is a C919 based AEWC in the works right now to replace KJ-500? KJ-700 as of right now seems to be a PLAN only aircraft and looking more closely it seems that it even has a surface search radar also it lacks refueling probe for long range patrols which is something presumably the PLAAF wants as new AEWCs all come with IFR probes(KJ-500A, KJ-3000). C919 has a larger MTOW and longer range compared to Y-9 and also better ergonomics for longer patrols, once CJ-1000A begins production a fully or mostly domestic militarised C919 would be possible IMO.