Permanency Conference?

Hey all, just a few questions about some things I havent' come across before. I have an adopted daughter, and two foster sons (who are also brothers), the older son, 18 months, who's birth mom just voluntarily relinquished her rights and the other son who is 9 months old that we have had since birth she decided not to sign for him yet and wanted to still have visits until the courts TPR'd her. She is also pregnant again and CPS has told her they are taking this baby as well, though he will not be coming to our home, she is aware of what's going on. So anyways I said all that to say this. My younger boy, who is 9 months and still having visits has his court date July 16th. We just went to mediation March 5th for both boys where she decided to sign for one and not the other. Well today, May 18th I get a letter of a permanency conference for next week on the youngest boy. I have never been to one nor ever notified of one. What is this? Is it like mediation? Or is it something that is routine and I was probably just never aware of? Is the birth mom going to be there and may she have changed her mind about signing over? Or is this some meeting to all get together and say yes your court is still in July where CPS plans to TPR her unless she signs? Has anyone ever been to one and what is it? Thanks so much, sorry if I wrote confusing.