When was that announced? This interview with the showrunner from December 8 explicitly states that they are not approaching this as the last season (yet).
TVLINE | Lastly, you seem to be pulling out all the stops lately. Are you consciously using this season as a chance to do all the things you’ve wanted to for so long?
Yeah, we really are. There have always been talks [of a final season], and the network has been so wonderfully supportive, … There’s definitely the fear of when you make things real — like Victoria knowing that Emily is Amanda Clarke — it’s like, “Well, where do we go from here?” But to the credit of our writing staff, any corner we paint ourselves into is exciting for us because we always figure out how to get out of it.
To say we’re approaching this as the last season would be wrong, but we’re not scared to make choices that will make people ask “Where is this going?”TVLine.com
"Some people can thrive and bloom living life in a living room, that's perfect for some people of one hundred and five. But I at least gotta try, when I think of all the sights that I gotta see, all the places I gotta play, all the things that I gotta be at"