The Facebook page and this link strongly suggest that the characters Sophie Larson and Vernon are leaving the show! I suppose there's room for the idea that they've finished shooting for this season only, but this is probably wishful thinking. I for one would hate to see them go and can't imagine how the show would proceed without them, but we'll have to wait and see.
Video short 4 shows a press conference taking place with Tom Taylor, this was also mentioned in another short I can't find at the moment.