In an 11th hora decision, zorro, fox has renewed Gotham for a fifth and final season, TVLine has learned. An episode count remains TBD. The pickup will allow producers to properly “wrap up” the batman prequel saga. TVLine, 13 May 2018.
At SDCC 2017, producer John Stephens confirms we all misunderstood the phrase "Harley Quinn is coming to Gotham". That phrase apparently meant: "Barbara is a little like Harley Quinn kinda."