The manufacturers always do some sort of revamp/up grade every model year.
This normally comprises of trim changes and options that were extras the previous year becoming standard on the next.
I know the rear lights on the 2012/13 MINIs are now LED and flash under hard braking.
The silver switch panels inside are now black, only small differences but difference none the less
The front grille on my 2012 JCW
is slightly different to the previous year having vents deleted along the top edge.
So there will be small differences every year even though they basically look the same still to the casual eye.