Not a new development for our AWAC program. Had Pakistan wanted or the Chinese wanted to provide AESA based platform to Pakistan, we would have gone with it, but we choose the other option, an ESA radar platform but not AESA.
This T0518 is a testing platform, meaning it first tested one set of radar set on it, once that was finalized and a production model made which we saw with the Air Chief Marshal pic in it, this testing platform had done its job and now it seems to have been fitted with a triangular placed AESA radar for testing and evaluation.
My hunch is its for the Chinese Air force as they had not inducted in numbers the linear shaped KJ-200 in numbers as it has certain deficiency with no 360 coverage, and their KJ-2000 platform is facing a problem due to non availability of IL-76/78 platforms from Russia, thus CAF may have now opted to get a 360 coverage capability by having a triangular placed AESA radar fitted to their own made Y-8 platforms, and this T0518 is the testing platform for this new concept to be tested out.
Our model has been made and most probably now in testing stage and improvements or modifications would be done based on the testing done on this PAF version of the AWAC.