The quotes below about her staying are from Beth Schwartz, the showrunner.
From this article:
Arrow Recap: Birds of a Feather — Plus, Has [Spoiler] Left the Show?
I know Katie/Laurel fans, for the most part, would be immensely happy for the show to give BC her dues. Wouldn't that be something for the fans - closing out Arrow with KC front and center.
I really thought her and EBR were leaving this season but it's only because I saw someone post about how they were finally free from the CW.
