I've read that too ... but I'm sceptical, very sceptical ... before I see it.
I am a Sceptical person, too.
But, There is a Possibility for that happen.
We already see Pictures of WS-20 on IL-76 a couple years ago. Maybe this is the right time to Test WS-20 on board Y-20.
if it is the case, it will be another milestone for Chinese high performance turbofan engine industry ... go go go China
China Military Development in 2015 already give many Surprises to me, especially for J-20 '2101'
and I cannot wait for Another Surprises this year.