Fiat has change entire electrical set-up for new tail lamp. If you wish to fit this under warranty yo need to change whole wiring. If you are not under warranty then you have to live with error in MID and able to use. As others said, new one has 5 pin socket than earlier 4 pin. So wiring need to be repalced too. If you can, you are good to go. Fiat is very cleaver.