Tu-154 Careless ELINT.

Before the introduction of the Y-8 based "high new"  specialized surveillance birds in the early 2000s, the PLAAF operated a small fleet of 4 locally modified  Tu-154 for electronic intelligence activities across the Taiwan strait.   Now with a more capable "high new" military airframe in full swing, the PLAAF brass might feel more comfortable in decommissioning those ad hoc Russian airliners.