Looking at a car for wifey which happens to have carplay for iphones. We used to have iphones and now have supermarket androids but if we get this car I was thinking of surprising her with a new but older model iphone like the iphone 6. Apart from all the tricks apple play, or used to with superseded models, is there any problem with a new iphone 6 and carplay?

I know the phone is a few years old but I don't care that it isn't the latest, just want it to work with the car. Thanks in advance.