The real question is what does Tennessee want from her as a "felon." Does Tennessee have felon registration requirements?
I'm a florida attorney, so I don't know, but perhaps you should post this question with Tennessee as the questioner's location. Also, here's a link that claims to have an answer for that question, but I am NOT vouching for the source: http://www.interstatecompact.org/LinkClick.aspx?fileticket=_z_GAg1xGwY%3D&tabid=105&mid=431
A more important question is what does Floirda want from her. If she was supposed to register or be on probation in Florida and did not comply she may well have warrants for her arrest in Florida including new charges for leaving the state without permission. She should consult privately with a criminal defense attorney in Florida, or her prior attorney to determine her options.
If she has violated her probation, she could be looking at prison time, if she has committed a new crime by not registering, she could also be looking at new jail or prison time.