This means also, that the expected lifetime of a phone is more than 20 years. It must be updateable and durable.

Impressive! More companies should think like that.

This is in relation to a concept of phone "body" combined with a replacable faceplate which would expose different functionality (additional buttons, slide-out keyboard). One year later they introduced "Xpress-on" covers, which seem to boil down to having different colors. A bit more mundane.