Saw this a few days ago but didn't have chance to post it till now.
The latest AFM mag has run a story which seem to confirm PLAAF Su27 or J11s participating in Turkey earlier this year.
It states that the F16 did not take part in the exercises following US concerns over security, so F4s were used instead.
It also reported that the Flankers and support aircraft landed in Iran for refueling both to and from the exercise.
I am unsure how much to trust this report. On the one hand, it has a lot of details which seem to be confirmed, but of the other, it reported the J11 as CAC built...
I will let you guys decide for yourselves whether you want to believe this.