Seat - mounted torso airbags for front seat occupants became standard beginning with 2014 models (they had been optional in earlier models). (iihs.org)
The improvements are enough that anyone with earlier models, especially 3 or 3G models, will feel the «need» to upgrade. (slaw.ca)
Side airbags and side curtain airbags were optional on early models; standard from 2008. (samarins.com)