According to my dealership when I bought my new 2015 ForFour, the factory halted all production of the forFour without notifying the dealers for around 3 months because they couldn't get the front armrest for the 2016 model to work properly.
I only found this out when I had an delivery date of 1 November, and the dealer contacted me to say it'll now be sometime late January!
I compromised on the spec so that I could get a car that had already been manufactured, but when I went to collect it from the dealership I met another customer who had ordered the automatic gearbox, and was as annoyed as me about the delays from the factory, and the fact they didn't tell the dealerships about the delays.