I took this picture when queuing up for a museum a few days ago. A senior person had added some stockers to his android phone.
The stickers are replica of the button. Apparently this person was struggling in seeing the button as they light up only when one touches them.
Senior people are not comfortable with unapparent features.
Nevertheless, this person in his 70s was using perfectly the device: doing searches on the Internet, checking emails, etc.
Adapting a smartphone to senior people is not just a question of interface. The whole user experience including hardware needs to be adapted. Fujitsu and Doro are struggling hard to seduce this new customer segment. But can it be done with a few stickers ?