Interesting, that it finally has the upwards facing exhausts fitted, which were shown at Zhuhai 2018. On the last image I found before (no. 2) it was still the old one facing to the sides.
Are these images all from the same base? I'm a bit confused since they are said to be from a unit called 镇川堡陆航试训团 (or the "Zhenchuanbao Aviation Training Team" ??) and at 37°52'28.0"N 110°04'14.2"E is indeed an air base I so far had not listed in my Orbat.