Over here in the Netherlands everyone uses Whatsapp. That includes family, colleagues, teachers, class mates, team mates, you name 'm. And nobody is going to switch to anything else very soon.
SMS is all but forgotten, MMS no longer works.
So, for the L5 to be workable chat device over here in Western Europe it definitely needs to speak fluent Whatsapp. (And It would be lovely if it manages to does this without selling its (and our) soul to the marketing devil,)